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Rochester Quadrajet 4MV Carburetor: Removal, Disassembly, Rebuild (Rookie Level)

152K views 144 replies 18 participants last post by  lt1silverhawk 
#1 ·
**If anything is mislabeled or the information is incorrect, please let me know! Thanks!


- Background -

I have a '77 Chevy pickup that became victim to water and debris in the gas tank (you can read up on that story here.)

At this point, due to the debris getting in the carburetor, it has to be rebuilt.

This is my first time rebuilding a carburetor as well as taking apart and putting together anything on a large scale.

The posts in this thread will be written in such a way as to provide a complete step-by-step documentation of everything I do (aka, sorry if this seems lengthy). This is for two reasons: 1) the other forum members who help out have all necessary information available and, 2) anyone of similar mechanical apptitude as me (which is very minimal) who finds this will be able to follow along without getting lost or intimidated.




- Research -

I began by searching all over the internet as well as local libraries for any guides that can walk me through this process.


I started by decoding the carburetor so I could purchase the proper repair kit. For Rochester, I used the following website: http://www.holisticpage.com/camaro/parts/carb.htm.


The code on this carburetor is 17057525 APP 3356. Based on the information provided by the website the carburetor is:
170 – Built: 1975 and onward by the Rochester Division of GM
5 – Decade produced: 1976 - 1979
7 – Year produced: 1977
5 – Model: Quadrajet (4bbl) California Standards
2 – Division: Chevrolet
5 – Transmission: manual (truck is an automatic)
APP- Customer code
3356- Build date code


With this information decoded, I moved onto to looking for guides on rebuilding these carburetors. Amazon carries a few titles on Rochester carburetors, but the most highly reviewed is “How to Rebuild and Modify Rochester Quadrajet carburetors” by Cliff Ruggles. It was also recommended by another forum member in another thread.


Aside from the book, I also found a couple of forums and websites where a rebuild had been documented. I found this one to be the most informative: http://www.vetteprojects.com/kstyer/quadrajet.htm


Another resource that may prove helpful is the original Delco manual that was uploaded online: http://www.tocmp.com/manuals/Carbs/Rochester/QJet/


Lastly, the one place that everyone can go to learn how to do practically anything is Youtube. Again, a few people took the time to create several videos to show how to rebuild a Rochester carburetor. Due to videos being constantly removed or updated, its best to go look for the newest materials.




- Removal -

The carburetor's removal comprised of the following steps:
1. Take pictures of the carburetor from every angle as it sits.
2. Label all hoses and connections to be removed. In this case, used masking tape since its easy to write on it.
3. Take pictures from every angle of the hoses as labeled.
4. Unbolt the carburetor and remove all hoses and connections (throttle cable, springs).
5. Remove the carburetor and take close-ups shots of everything.




Step 1:





Steps 2 and 3:





Step 5:










- Rebuild Kit -

I purchased a Hygrade brand rebuild kit and float. As warned in the other thread, the instructions do leave much to be desired.

 
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#27 ·
the best advise i can give u is trash your quadrajunk. ive got one in a million peaces on my back porch that can tell the story of endless nightmares. they are the best carbs to have when thet work good but once the go bad its damn near impossible to get them right again. get yourself an edelbrock, u wont regreat it. if your quadrajet meens something to you then fix it, i got tons of parts lol
 
#29 ·
Hey Josh,

Josh dalrymple said:
the best advise i can give u is trash your quadrajunk. ive got one in a million peaces on my back porch that can tell the story of endless nightmares. they are the best carbs to have when thet work good but once the go bad its damn near impossible to get them right again. get yourself an edelbrock, u wont regreat it. if your quadrajet meens something to you then fix it, i got tons of parts lol
Lol! My original thought was to ditch the Qjet as well and throw on a Holley I've got sitting around. But after several people mentioned that this setup will indeed be the best one - once its properly tuned - it just seemed like a good opportunity to learn something new and get over my fear of carburetors (and we all fear what we don't understand). While everything has been pretty much smooth sailing so far, due in large part to all the help from the members of this forum, I hit my first bump in the road with the power piston. But if anything makes me nervous now, it is definitely the tuning.

How many parts you got? I just may tackle another one lol! :D




-------------------




cobalt327 said:
The best tool for this job is the blunt end of a #70 drill bit.

Click on image for the site the image is from. Hobby shops also carry these small bits. The common sets range from #61 (0.039") to #80 (0.0135").
Sweet! I'm sure I can pick it up localy. Thank you for your continued help Cobalt!
 
#30 ·
You are quite welcome. FWIW, there are a LOT of threads on working w/the Q-jet here on the forum. If you haven't yet done so, a search might be of some use to you.

There are a few tips and tricks, like placing a ~0.050" feeler behind the accelerator pump lever pin, so when you drive the pin towards the air horn lip it doesn't butt tightly against it- instead there's room to get a thin straight blade screwdriver in behind it to lever the pin back into position.

There are several different heads to the idle mixture screws: hex, flat blade slot, and one is an ovoid/hex affair that defies all logic- other than to make it difficult to turn. You'd have thought that capping the screws would have been enough, but I suppose this was extra insurance that they wouldn't be tampered with.

Anyway, these ovoid screws can be removed by using a crimped length of brass tubing, found at hobby shops. Once these bastard screws are out, use a dremel and a cutting disc to put a slot in them for a standard screwdriver. I do this to ALL my carb's idle mixture screws, because finding the right sized 1/4" drive deep socket is only half the battle- the OD of the socket has to be ground down in many cases in order for the socket to fit into the available space.

Early Q-jets had accelerator pump and choke linkages that were secured by small clips. If you can get your hands on these, they make dis- and re-assembly easier (especially the acc. pump link).

For some reason, I have found the base plate on many Q-jets to be missing a screw or two. While the base plate is "helped" being held on by the two long front bolts, it's still a good idea IMO to go ahead and add the missing screws. Just be sure to not over tighten these long bolts. If they're over tightened, it can warp the carb beyond use.

Check the base plate to be sure the throttle blades are exactly 90° when wide open. There are some who believe having the secondary throttle blades go "over center" helps w/A/F distribution w/some intakes. While this may be true, until you have a good grasp on the engine's tune and plug readings indicate a need for this, keep them @ 90°.

I don't want to get you sidetracked w/a lot of tuning 'advice', this being a primer for dis- and re-assembly. But this is an easy cure for a common problem you might run into:

The idle discharge ports that are controlled by the idle mixture screws can be anywhere from around 0.050" to 0.080". If you find a lean idle condition that doesn't seem to respond to turning out the screws CCW, you can gauge the port size then enlarge it one size at a time until you regain control w/the screws.

This is providing that the throttle plates are not open too far due to a large cam- which will over-expose the transfer slot, just like on a Holley. The cure for that is the same as you'd do w/a Holley- start by using more ignition advance. This allows the primary throttle blades to be closed down some to lower the idle speed, which increases due to the advanced timing. Often, this is all that's needed, so be sure to do this FIRST, then enlarge the ports only if still needed.

A common problem on the early Q-jets especially, is leaky main wells.

The 'cure' for this has long been to use JB Weld, etc. to seal them over. This is just a stop-gap measure, I have seen personally how the epoxy will degrade over time and quit sealing as it did at first.

If a permanent fix is wanted, the wells can be resealed w/new plugs that are peened over to hold them in place.

The primary wells can be drilled and tapped for short screws that will cure them for good, although these wells seldom leak.

One last thing before this gets any more long-winded. On the secondary accelerator 'pump' discharge ports that are often located above the air valve- these are better located just below the closed blades. The upper ports can be sealed off w/epoxy on a clean, roughed up surface then the same size ports located under the blades, in line w/the existing holes.

Only do this if you are experiencing a lag or slight bog that doesn't respond to the usual fixes- like the air valve spring tension adjustment or the unloader orifice size.

The center two round gaskets are for the two different types of fuel filter housing/inlet fittings that were used. One uses the white nylon gasket on the very end of the housing, the other type used the orange gasket all the way to the end of the threads. If there's a lip on the end of the housing that will accept the white nylon gasket- use it, not both.

 
#31 ·
cobalt327 said:
You are quite welcome. FWIW, there are a LOT of threads on working w/the Q-jet here on the forum. If you haven't yet done so, a search might be of some use to you.
Oh yes, I have been searching and reading like crazy on this forum as well as others. Lots of info on turning it, which makes me a little less nervous since I don't know what to listen or look for right away. This will be a trial-and-error kind of lesson.




cobalt327 said:
There are a few tips and tricks, like placing a ~0.050" feeler behind the accelerator pump lever pin, so when you drive the pin towards the air horn lip it doesn't butt tightly against it- instead there's room to get a thin straight blade screwdriver in behind it to lever the pin back into position.
Im glad you mentioned this. I was planning on reusing the old pin because I thought it might be a bit of a hassle to replace it and the original seems to fit snugly. I do need to invest in a feeler gauage and this tip will help in installing the pin correctly.




cobalt327 said:
There are several different heads to the idle mixture screws: hex, flat blade slot, and one is an ovoid/hex affair that defies all logic- other than to make it difficult to turn. You'd have thought that capping the screws would have been enough, but I suppose this was extra insurance that they wouldn't be tampered with.

Anyway, these ovoid screws can be removed by using a crimped length of brass tubing, found at hobby shops. Once these bastard screws are out, use a dremel and a cutting disc to put a slot in them for a standard screwdriver. I do this to ALL my carb's idle mixture screws, because finding the right sized 1/4" drive deep socket is only half the battle- the OD of the socket has to be ground down in many cases in order for the socket to fit into the available space.
The screws in this carburetor are the flat blade type, but Im glad you mentioned this because this information will definitely help someone else out. And I will also know what to look out for if I ever rebuild another one.




cobalt327 said:
Early Q-jets had accelerator pump and choke linkages that were secured by small clips. If you can get your hands on these, they make dis- and re-assembly easier (especially the acc. pump link).
These clips are available on quadrajetparts.com and carburetion.com. Since I will most likely be buying the power piston bushing, I'll add the clips to my order.




cobalt327 said:
For some reason, I have found the base plate on many Q-jets to be missing a screw or two. While the base plate is "helped" being held on by the two long front bolts, it's still a good idea IMO to go ahead and add the missing screws. Just be sure to not over tighten these long bolts. If they're over tightened, it can warp the carb beyond use.
Sorry, I am confused on this one. Do you mean the two bolts that attach the carburetor to the intake manifold or the the two bolts that attach the base plate (throttle body) to the float bowl?




cobalt327 said:
Check the base plate to be sure the throttle blades are exactly 90� when wide open. There are some who believe having the secondary throttle blades go "over center" helps w/A/F distribution w/some intakes. While this may be true, until you have a good grasp on the engine's tune and plug readings indicate a need for this, keep them @ 90�.
I haven't looked at these yet but will check tonight. I've also read that there can be some play in this area but not sure how to "tighten" it up. Any suggestions?




cobalt327 said:
I don't want to get you sidetracked w/a lot of tuning 'advice', this being a primer for dis- and re-assembly. But this is an easy cure for a common problem you might run into:

The idle discharge ports that are controlled by the idle mixture screws can be anywhere from around 0.050" to 0.080". If you find a lean idle condition that doesn't seem to respond to turning out the screws CCW, you can gauge the port size then enlarge it one size at a time until you regain control w/the screws.

This is providing that the throttle plates are not open too far due to a large cam- which will over-expose the transfer slot, just like on a Holley. The cure for that is the same as you'd do w/a Holley- start by using more ignition advance. This allows the primary throttle blades to be closed down some to lower the idle speed, which increases due to the advanced timing. Often, this is all that's needed, so be sure to do this FIRST, then enlarge the ports only if still needed.
OK, this will be something I will need to look up because Im not sure what part this is. But again, good to know in advance.




cobalt327 said:
A common problem on the early Q-jets especially, is leaky main wells.

The 'cure' for this has long been to use JB Weld, etc. to seal them over. This is just a stop-gap measure, I have seen personally how the epoxy will degrade over time and quit sealing as it did at first.

If a permanent fix is wanted, the wells can be resealed w/new plugs that are peened over to hold them in place.

The primary wells can be drilled and tapped for short screws that will cure them for good, although these wells seldom leak.
I was originally considering using JB Weld. The author of the video series I've been watching on Youtube that details the Qjet tear down and rebuild recommended the use of 5 minuet epoxy and and that's what I need up using yesterday. I did discuss it with the manager of the local Autozone and he did caution that, while the heat resistance is fine (over 200 degrees F), nowhere on the packaging did it say that the epoxy is resistant to gasoline. I imagine I would have to take the carburetor to a professional for the permanent fix you mentioned.




cobalt327 said:
One last thing before this gets any more long-winded. On the secondary accelerator 'pump' discharge ports that are often located above the air valve- these are better located just below the closed blades. The upper ports can be sealed off w/epoxy on a clean, roughed up surface then the same size ports located under the blades, in line w/the existing holes.

Only do this if you are experiencing a lag or slight bog that doesn't respond to the usual fixes- like the air valve spring tension adjustment or the unloader orifice size.
This will be another part I will need to look up further. Im hoping it won't get to this but at least I will know what to expect.




cobalt327 said:
The center two round gaskets are for the two different types of fuel filter housing/inlet fittings that were used. One uses the white nylon gasket on the very end of the housing, the other type used the orange gasket all the way to the end of the threads. If there's a lip on the end of the housing that will accept the white nylon gasket- use it, not both.

Thanks for pointing that out, 'cause I was gonna toss 'em! :D Any idea what the little cork gasket is for?



Colbat, I cannot thank you enough for putting in all this time and effort in making this information available, and in such a straight forward and easy to understand format. This is going to help me and anyone else who refers to this thread tremendously. :D
 
#32 ·
lt1silverhawk said:
These clips are available on quadrajetparts.com and carburetion.com. Since I will most likely be buying the power piston bushing, I'll add the clips to my order.
Just the clips won't help unless you also have the links w/the small hole or groove in/on it, depending on the style of clip that's used. The clips are often included in the rebuild kits since the kits cover many different carbs.

Sorry, I am confused on this one. Do you mean the two bolts that attach the carburetor to the intake manifold or the the two bolts that attach the base plate (throttle body) to the float bowl?
The front long bolts that go all the way through the carb to the intake.

Something else comes to mind in this area- and that's to tighten the carb to the thick insulator-type gasket evenly but not too tightly. Because the gasket of that type has a lot of give to it, it can cause the base plate to warp- sometimes enough to cause the throttle shafts/blades to bind.

I haven't looked at these yet but will check tonight. I've also read that there can be some play in this area but not sure how to "tighten" it up. Any suggestions?
Usually the play will be on the primary shaft. The shaft is teflon coated (that green colored material) but despite this, the shaft wears directly on the aluminum of the throttle plate. There are bushing kits to fix this if it's worn too much.

How much is too much? If you get an erratic idle or if it's obviously worn out. There will be play in ALL of them, though and that's where determining how much is too much is tricky. But if it idles good, it's good to go, IMO.

OK, this will be something I will need to look up because Im not sure what part this is. But again, good to know in advance.
If you take the idle mixture screw out, it's the hole at the end of the threads.

I was originally considering using JB Weld. The author of the video series I've been watching on Youtube that details the Qjet tear down and rebuild recommended the use of 5 minuet epoxy and and that's what I need up using yesterday. I did discuss it with the manager of the local Autozone and he did caution that, while the heat resistance is fine (over 200 degrees F), nowhere on the packaging did it say that the epoxy is resistant to gasoline. I imagine I would have to take the carburetor to a professional for the permanent fix you mentioned.
JB Weld will work, just not permanently, is all. I believe Ruggles has the plugs and possibly the primary screws should they be needed. But it's almost always the older (702/704xxxx carb numbers that have the problem. Newer carbs used a better plug arrangement and usually don't leak.

Another thing that is a stop-gap measure at best for a leaky well, is those black, 1/4"-3/16" thick foam rubber pieces that most carb kits include. They will work for a while, but are not permanent.

This will be another part I will need to look up further. Im hoping it won't get to this but at least I will know what to expect.
Don't even worry about this, unless "you are experiencing a lag or slight bog (when the secondaries open up) that doesn't respond to the usual fixes- like the air valve spring tension adjustment or the unloader orifice size."

Any idea what the little cork gasket is for?
It goes between the choke and carb body on hot air-type chokes.

Like you said, hopefully this will help someone doing a search, and because of your descriptive title, I was more inclined to add to your thread, so good job w/that. All too often, threads will get a title like, "Need Help". Or "Problem With My Engine".
You know that any info in the thread will die w/the thread.
 
#33 ·
cobalt327 said:
Just the clips won't help unless you also have the links w/the small hole or groove in/on it, depending on the style of clip that's used. The clips are often included in the rebuild kits since the kits cover many different carbs.
I must admit that I am rather disappointed with this rebuild kit. I picked up thinking it would be a complete kit, but now it seems rather incomplete when compared to what others say should be included. For instance, there is no accelerator pump.




cobalt327 said:
The front long bolts that go all the way through the carb to the intake.

Something else comes to mind in this area- and that's to tighten the carb to the thick insulator-type gasket evenly but not too tightly. Because the gasket of that type has a lot of give to it, it can cause the base plate to warp- sometimes enough to cause the throttle shafts/blades to bind.
Got it. There were four bolts when I removed the carburetor; two long ones in the front and two short ones in the back. I will take special care not to over-tighten the bolts when reinstalling.




cobalt327 said:
Usually the play will be on the primary shaft. The shaft is teflon coated (that green colored material) but despite this, the shaft wears directly on the aluminum of the throttle plate. There are bushing kits to fix this if it's worn too much.

How much is too much? If you get an erratic idle or if it's obviously worn out. There will be play in ALL of them, though and that's where determining how much is too much is tricky. But if it idles good, it's good to go, IMO.
I will check for play but I will say, before rebuild, the idle seemed fine, though a bit low.




cobalt327 said:
If you take the idle mixture screw out, it's the hole at the end of the threads.
Got it.




cobalt327 said:
JB Weld will work, just not permanently, is all. I believe Ruggles has the plugs and possibly the primary screws should they be needed. But it's almost always the older (702/704xxxx carb numbers that have the problem. Newer carbs used a better plug arrangement and usually don't leak.

Another thing that is a stop-gap measure at best for a leaky well, is those black, 1/4"-3/16" thick foam rubber pieces that most carb kits include. They will work for a while, but are not permanent.
This carburetor is a (1)7057525, making it a 1977. I am hoping that since a layer of silicone was used to seal the wells in a previous rebuild, it doesn't have any leaks and the silicone was just precautionary.




cobalt327 said:
Don't even worry about this, unless "you are experiencing a lag or slight bog (when the secondaries open up) that doesn't respond to the usual fixes- like the air valve spring tension adjustment or the unloader orifice size."
Not sure if it is related, but before the truck became victim of water and debris in the gas tank, it did suffer from slight hesitation / slight bog.




cobalt327 said:
It goes between the choke and carb body on hot air-type chokes.
Then I won't be needing it since this one has the divorced choke.




cobalt327 said:
Like you said, hopefully this will help someone doing a search, and because of your descriptive title, I was more inclined to add to your thread, so good job w/that. All too often, threads will get a title like, "Need Help". Or "Problem With My Engine".
You know that any info in the thread will die w/the thread.
LOL! I'm glad my geeky work skills and an obsession with organization are paying off! I completely agree with you about the titles; nothing throws off a person more than a generic title that doesn't say what the thread is about. I'm sure I have passed over many a good threads with bad titles.



So, for now, I'll be ordering a new accelerator pump as well as the power piston retainer. I am considering new jets but don't know how to tell what size they are. In any case, the originals seem to have cleaned up well. I will also be buying the bit mentioned in the earlier post to clean out the two orifices.

In the mean time, if you feel that something else requires attention, please do point it out! :thumbup:
 
#34 ·
I don't want to rain on your parade but I think you are being penny wise and pound foolish by not investing in Cliff's book. There are some very simple and cost effective modifications he recommends for even a stock rebuild which will enhance the performance and reliability of the carb and greatly increase the chance of a successful rebuild. The lean idle qualities and accelerator pump circuit of the emissions era quadrajets specifically need to be addressed.

BTW he recommends Devcon Marine-Tex epoxy as the only permanent well plug sealing material he has found.

He is a great source for parts and has a forum where you can get advice and feedback on your rebuild. His rebuild kits are a little pricey but would have addressed some of the parts issues you have described.

Just my 2 cents. Take it for what its worth.
 
#35 ·
The jet and rod sizes are stamped into them. The jets have the number on the top surface as you look down at them orientated as if they were installed.

The rods (primary and secondary) have the size stamped onto the rod, you'll need to look for it, possibly use magnification (I do, but my eyes are old).

Earlier carbs used a jet that was about 30 numbers larger than the rod number. Later carbs the spread was less. This depends on the air bleed type, etc. and isn't anything you need be overly concerned with at this point- I would reassemble the carb w/the stock primary jets and rods first before changing anything. Then after the engine has run long enough for you to get ahold of the traits and plug readings you see, changes can be made if needed.

I have heard the Ruggles and Roe books are good. Most guys seem to say they like the Ruggles book better- it spells out "recipes" for different engine scenarios that can be followed.

People like to be told: "do this and then do that", rather than having to figure things out for themselves. This is fine, but leaves me wondering if that method actually helps anyone to actually understand the "cause and effect" of why a change does this or that.

But I digress- the book has had good reviews (that I assume also equates to successful carb builds), and I suppose that's what matters most.
 
#36 ·
Hey TommyK,

TommyK said:
I don't want to rain on your parade but I think you are being penny wise and pound foolish by not investing in Cliff's book. There are some very simple and cost effective modifications he recommends for even a stock rebuild which will enhance the performance and reliability of the carb and greatly increase the chance of a successful rebuild. The lean idle qualities and accelerator pump circuit of the emissions era quadrajets specifically need to be addressed.

BTW he recommends Devcon Marine-Tex epoxy as the only permanent well plug sealing material he has found.

He is a great source for parts and has a forum where you can get advice and feedback on your rebuild. His rebuild kits are a little pricey but would have addressed some of the parts issues you have described.

Just my 2 cents. Take it for what its worth.
First off, I'm glad you brought up all of this. :)

I have read nothing but good reviews on Cliff Ruggle's "How to Rebuild and Modify Rochester Quadrajet Carburetors". Its true, I did try to cheap out by not buying the book and resorted to look for online articles and help instead. I actually tried to borrow one but that never worked out. However, now it only seems wise to buy a copy and read it thoroughly. (I'm working on a part timer's budget).

I never knew that there was an online shop/forum run by Cliff (Cliff's High Performance Quadrajets). Reading the previous posts, I noticed that cobalt327 did mention Ruggles as a good place for plugs but I never got a chance to look into what it was. Frankly, I am rather amazed that his website never came up when I was researching online. I like the fact that they can custom build a customer's rebuild kit and the starting price is the same as what I paid for my kit plus a new float. I did see the Devcon Marine-Tex epoxy. $20 plus shipping seems bit much but if it gets the job done then, I'll fork it out.

I'm going to try and purchase everything I need from Cliff's site, but I must say I couldn't find the power piston retainer anywhere on the site so I will inquire about that.

Since I have been picking everyone's brains on this forum, and several members have taken the time and energy to contribute tons of useful information on this rebuild, I will continue documenting it here. It is actually a part of another project which the forum members have been helping me with. However, I will now also use Cliff's forum to obtain any other necessary information and feedback. I am going to be away for a week so I'll probably do some reading then. (As of this writing, it seems that the big man has been out due to surgery and is still recovering).

TommyK, your two cents are worth alot more than that. Thank you for sharing this information. It has already helped me out and it will help someone in the future. :thumbup:




--------------------------




Good morning cobalt327!

cobalt327 said:
The jet and rod sizes are stamped into them. The jets have the number on the top surface as you look down at them orientated as if they were installed.

The rods (primary and secondary) have the size stamped onto the rod, you'll need to look for it, possibly use magnification (I do, but my eyes are old).

Earlier carbs used a jet that was about 30 numbers larger than the rod number. Later carbs the spread was less. This depends on the air bleed type, etc. and isn't anything you need be overly concerned with at this point- I would reassemble the carb w/the stock primary jets and rods first before changing anything. Then after the engine has run long enough for you to get ahold of the traits and plug readings you see, changes can be made if needed.

cobalt327 said:
I have heard the Ruggles and Roe books are good. Most guys seem to say they like the Ruggles book better- it spells out "recipes" for different engine scenarios that can be followed.
I have seen the same; people do seem to prefer the Ruggles book over Roe's. I was able to read portions of Doug Roe's "Rochester Carburetors" online and it seemed detailed and straight-forward.




cobalt327 said:
People like to be told: "do this and then do that", rather than having to figure things out for themselves. This is fine, but leaves me wondering if that method actually helps anyone to actually understand the "cause and effect" of why a change does this or that.
I must admit that, for my style of learning, when I am working on something that I have zero knowledge (much like in this case)I prefer to be told what to do the first time around, with a simple explanation of "why". But after that, if I tackle the same job again, I find myself asking more detailed questions because I have some confidence and know what I am looking at. Which is why I have reread everything you and other members have posted several times over.




cobalt327 said:
But I digress- the book has had good reviews (that I assume also equates to successful carb builds), and I suppose that's what matters most.
At this point, i think it is safe to say that this book definitely has a strong following (the one unhappy reviewer on Amazon complained about the fact that the author didn't go into the competition modifications). Well, its now on the shopping list.



Final shopping list (until something else comes up :)): Power piston retainer bushing, accelerator pump, the bit for cleaning the orifices, and a copy of Ruggle's book.




By the way, cobalt327 and the rest of the forum members, I do wanna say that, due to circumstances in life, you guys are the closest thing to a shop teacher I may ever have, with this forum as the classroom and textbook. I really look forward to reading everything you guys have to say and teach. :thumbup:
 
#37 ·
Post #22 has a link to the split retainer for the PP if Ruggles doesn't carry them. Gessler also has most- if not all- of the hard to find small parts you could ever need.

Have you seen "Lars'" info on the Q-jet? If not, google "lars q-jet".

If the well plugs aren't leaking- leave them alone! The carb you have usually does NOT have this problem.
 
#38 ·
cobalt327 said:
Post #22 has a link to the split retainer for the PP if Ruggles doesn't carry them. Gessler also has most- if not all- of the hard to find small parts you could ever need.
Yes, I did find the retainer on the Quadrajetparts.com. I didn't realize it was owned by Gessler. I was pricing my order on their site yesterday and it wasn't too bad. Had I known about them before, I would've taken advantage of the free shipping and ordered everything from their site.




cobalt327 said:
Have you seen "Lars'" info on the Q-jet? If not, google "lars q-jet".
I just looked it up and wow! I've got some serious reading ahead of me (definitely feels like I'm back in school :D ). Here is a version in MS Word format




cobalt327 said:
If the well plugs aren't leaking- leave them alone! The carb you have usually does NOT have this problem.
Yeah, I plan on leaving them be. To me, it seems the previous rebuilder had put a coat of silicone over the wells simply as a precaution. Besides, the epoxy has hardened and I haven't a clue how to remove it (aside from the Chem Dip, I suppose).
 
#39 ·
Just wanted to give an update on a few things (aka, a late night rant about nothing :D )...


I went ahead and ordered Cliff Ruggle's "How to Rebuild and Modify Rochester Quadrajet Carburetors", which should arrive this week. Since I am going to be away for a week, I'll go ahead and read up on it, along with Lars Grimsrud's "How to Tune a Q-Jet".


I went to Quadrajetparts.com, Carburetion.com, and Cliff's High Performance to price out my order for an accelerator pump, a power piston retainer bushing and a primary metering rod retaining spring for the power piston (mine seems a bit funky when compared to the way the new ones look).


While shopping for these parts, I noticed that sometimes the year application for certain parts didn't match up to what my carburetor currently has. For example, when searching for the primary metering rod retaining spring, I noticed on Quadrajetparts.com, the website says the spring I currently have (it is the oval-shaped one) is used in 1974 an earlier models (mine is a '77). For 1975 and up, the website shows this one.


An inconsistency I noticed between the three sellers is the correct choke pull-off (I'm not buying one, but was merely curious to see how much a replacement is). By matching up what I have with the pictures on the website (which can always be incorrect), I determined that I have what Cliff's refers to as the Chevrolet Straight-Inlet. However, while Cliff's website says it is applicable for years 1971-74, both Quadrajetparts.com says it for 19737-78 and Carburetion.com says it is for 1972-78. Of course, this is nothing that can't be clarified by contacting the sellers but just wanted to mention this for anyone else who does a price comparison with the three sellers.


All this prompted me to look up C & J Engineering, the local performance shop which at some point worked on my carb (they placed a small sticker for their company on the front of the carb that has since come off due to the dip). If something doesn't make sense, I figure I can always try and ask them about it as well.


So for now, I have decided to hold off on buying any replacement parts until I've read through the book and at least cleared up on the primary metering rod retaining spring.


I should be getting back to completing this in about a week and a half.


As always, thanks for the continued help! :thumbup:
 
#40 ·
I most often see the 'squared' primary rod retainer clip (below) used on the APT equipped carbs ('75-up). It is what is on the '86 non-feedback 4.3L Q-jet I have- that also has the larger 800 CFM casting, oddly enough.



I went back and looked at your PP. Your carb doesn't have APT by the looks of things, the PP would have a pin coming out of it near the top. So despite what the numbers say (you're sure of them?), it seems this is an earlier-type carb.

If you were ever interested in finding or needing a 800 CFM Q-jet, the easiest way by far is to source one from a late model truck, including the 5.7 and 5.0 V8's and the 4.3L V6 up to '86 they can be found as non-feedback w/"good" HEI distributors, too (w/o feedback; w/vacuum and mechanical advance).

About the PP retainer- I seem to remember some older carbs ('74-'75 and older?) using the metal clip retainer for the PP rather than the plastic clip. The years I cite may be off, but I'd want to look into your PP to be sure it ever used the plastic bushing/retainer in the first place- especially now that it appears the carb is an earlier design.

In any event, the numbers can be different than the published info. The 1705xxxx does usually mean '76-'79, though.
 
#41 ·
Hey cobalt!

cobalt327 said:
I most often see the 'squared' primary rod retainer clip (below) used on the APT equipped carbs ('75-up). It is what is on the '86 non-feedback 4.3L Q-jet I have- that also has the larger 800 CFM casting, oddly enough.



I went back and looked at your PP. Your carb doesn't have APT by the looks of things, the PP would have a pin coming out of it near the top. So despite what the numbers say (you're sure of them?), it seems this is an earlier-type carb.
...
In any event, the numbers can be different than the published info. The 1705xxxx does usually mean '76-'79, though.
Yes, the numbers on carburetor are correct. I meant to post a picture of it at one point but thought it might be overkill at the time.

I decoded the numbers using Holistic Page's carburetor page. And according to Recarbo's website, apparently "it is a documented fact that Rochester didn't follow these rules 100%". When I disassembled the carburetor, I did not see a APT screw in there. Maybe I missed it?




cobalt327 said:
If you were ever interested in finding or needing a 800 CFM Q-jet, the easiest way by far is to source one from a late model truck, including the 5.7 and 5.0 V8's and the 4.3L V6 up to '86 they can be found as non-feedback w/"good" HEI distributors, too (w/o feedback; w/vacuum and mechanical advance).
I'm not sure what cfm mine is but I've read that majority of the 4 bbl were 750 cfm. Is there a big difference between the 750 and 800 cfm versions? (I will admit that at this point, I have no clue what the significance of "w/o feedback; w/vacuum and mechanical advance" is.)




cobalt327 said:
About the PP retainer- I seem to remember some older carbs ('74-'75 and older?) using the metal clip retainer for the PP rather than the plastic clip. The years I cite may be off, but I'd want to look into your PP to be sure it ever used the plastic bushing/retainer in the first place- especially now that it appears the carb is an earlier design.
When I took the carburetor apart, I do not recall ever removing any type of retainer bushing or clip from the PP. And I was photographing every step of the way. To me, it seems like the PP was held in position using the gasket between the float bowl and the air horn, with the air horn's weight providing the necessary pressure. Below are some recent pictures of the PP and float bowl, after cleaning and powdercoating. I can post larger ones if needed. I will also post a picture of the retainer spring in its present condition.
 
#42 · (Edited)
apparently "it is a documented fact that Rochester didn't follow these rules 100%". When I disassembled the carburetor, I did not see a APT screw in there. Maybe I missed it?
You didn't miss it, the carb doesn't have APT like you'd expect it to have. Which brings us back to the italicized statement above about the less-than-100% certainty of the numbers being always correct. This is an obvious case where the numbers do not jibe w/what the carb actually is.

You should use something to carefully measure the length of the primary rods from tip to tip. The later carbs ('68-up) used a rod that is 2.4" long. The earlier carbs use a rod that's slightly longer.

There were cases of the longer 703xxxx-style primary rods being used in marine-type 170xxxxx stamped carbs. But these carbs also often used the earlier pivot float- which your carb doesn't have (which is a good thing, the earlier pivot/large float carbs were touchier re fuel pressure).

I'm not sure what cfm mine is but I've read that majority of the 4 bbl were 750 cfm. Is there a big difference between the 750 and 800 cfm versions?
From an earlier THREAD I posted to:
cobalt327 said:
1976-‘86 pickups, vans and medium duty trucks are a great source for 170-prefix 800 CFM carbs. All engines could have (and most DID have) the 800 CFM, even the 4.3L V6.

FWIW, the original carb on my '86 Sierra 4.3L V6 is a 800 CFM, w/forward-pointing fuel inlet.

As seen looking down into an assembled carb:
750 CFM-


800 CFM-



Below- as seen disassembled, the top image is of a 800 CFM venturi, 750 FCM below it. Arrow (above) and circle (below) indicate the 'bulge' seen only on the 800 CFM versions:

Until the later trucks, the 750 was much more common, the 800 was considered to be a "find".

But there is no real advantage to the 800 casting, IMO- unless you have an engine that actually NEEDS the extra flow.

The downside to the 800 CFM casting is the primary venturi is larger. This give slightly less response, although it is still better than most every other carb design due to the multiple booster arrangement.

The difference in airflow between the 750 and 800 carb:

Primary Flow for the Q-jet

175 to 185 CFM for 750CFM Q-jets

210 CFM to 225 CFM for 800 CFM Q-jets.

The 225 CFM figure is only for the one-year-only '71 Pontiac 455 HO 4M Q-jet. It lacked the outer booster rings found in the other carbs.

I will admit that at this point, I have no clue what the significance of "w/o feedback; w/vacuum and mechanical advance" is.
Cars from '81-up and trucks (some as late as '87-up) used a feedback-type carb and distributor to work w/the "CCC" (Computer Command Control) emissions system of the day. The carbs are not good for modifying for use w/o a computer, the distributors lack a vacuum advance and some both vacuum AND mechanical advance, so are not good for use w/o a computer, either.

So basically, "feedback" equals computer controlled.

When I took the carburetor apart, I do not recall ever removing any type of retainer bushing or clip from the PP. And I was photographing every step of the way. To me, it seems like the PP was held in position using the gasket between the float bowl and the air horn, with the air horn's weight providing the necessary pressure.
I don't recall there being a PP that didn't have either a plastic or a steel clip retainer. But before I would bank on it, I would ask Ruggles or another carb expert what their take on it was. It wouldn't surprise me to hear there was a short run of carbs that used nada to retain the PP- but I do tend to doubt it.
 
#43 ·
You have a picture in post 24 that looks like it shows the PP with the retainer on it. It is not uncommon for the retainer to fail to positively secure the PP in its hole in and of itself. The solution is to take a chisel and gently stake the edge of the hole in one or two spots against the retainer.

Its in the book!LOL! :D
 
#44 · (Edited)
cobalt327 said:
You should use something to carefully measure the length of the primary rods from tip to tip. The later carbs ('68-up) used a rod that is 2.4" long. The earlier carbs use a rod that's slightly longer.

There were cases of the longer 703xxxx-style primary rods being used in marine-type 170xxxxx stamped carbs. But these carbs also often used the earlier pivot float- which your carb doesn't have (which is a good thing, the earlier pivot/large float carbs were touchier re fuel pressure).
Well it was gonna happen sooner or later: time to buy a caliper!




cobalt327 said:
From an earlier THREAD I posted to:
I don't think you meant to do it but the link comes back to this thread. :)




cobalt327 said:
Until the later trucks, the 750 was much more common, the 800 was considered to be a "find".

But there is no real advantage to the 800 casting, IMO- unless you have an engine that actually NEEDS the extra flow.

The downside to the 800 CFM casting is the primary venturi is larger. This give slightly less response, although it is still better than most every other carb design due to the multiple booster arrangement.

The difference in airflow between the 750 and 800 carb:

Primary Flow for the Q-jet

175 to 185 CFM for 750CFM Q-jets

210 CFM to 225 CFM for 800 CFM Q-jets.

The 225 CFM figure is only for the one-year-only '71 Pontiac 455 HO 4M Q-jet. It lacked the outer booster rings found in the other carbs.
Excellent info! From what I can tell by comparing the pictures to my carb's pictures, its definitely a 750 cfm.



cobalt327 said:
Cars from '81-up and trucks (some as late as '87-up) used a feedback-type carb and distributor to work w/the "CCC" (Computer Command Control) emissions system of the day. The carbs are not good for modifying for use w/o a computer, the distributors lack a vacuum advance and some both vacuum AND mechanical advance, so are not good for use w/o a computer, either.

So basically, "feedback" equals computer controlled.
Thanks for clearing up yet another mystery :)




cobalt327 said:
I don't recall there being a PP that didn't have either a plastic or a steel clip retainer. But before I would bank on it, I would ask Ruggles or another carb expert what their take on it was. It wouldn't surprise me to hear there was a short run of carbs that used nada to retain the PP- but I do tend to doubt it.
I'm gonna talk to the members on Cliff's forum and see what I can find out.




Cobalt327, you are on a roll! :thumbup:




-----------------------------




Hey TommyK,

TommyK said:
You have a picture in post 24 that looks like it shows the PP with the retainer on it. It is not uncommon for the retainer to fail to positively secure the PP in its hole in and of itself.
Yes, there is a cap at the top that does move up and down but doesn't fit snugly in the tube for the PP. But it doesn't seem damaged in any way either, at least to my untrained eyes.




TommyK said:
The solution is to take a chisel and gently stake the edge of the hole in one or two spots against the retainer.

Its in the book!LOL!
I'll believe it when I see it lol! :D The book should be here today or tomorrow.
 
#45 ·
Tommy has good eyes!

The retainer collar IS on the PP (below). It has become loose over time, and if too loose, staking it into position might not be a good idea (but it IS an option for a slightly loose retainer), unless a replacement couldn't be found. But Gessler has the split collar type for a couple bucks, so...

At least there's no more wondering on my part whether it used the steel retainer or what. Mystery solved.



AFA "on a roll", w/the good title, hopefully this thread will get used, and early on dinger (a mod) asked about putting it in the knowledge base- so all the more reason to put a little effort into it.
 
#46 ·
cobalt327 said:
Tommy has good eyes!

The retainer collar IS on the PP (below). It has become loose over time, and if too loose, staking it into position might not be a good idea (but it IS an option for a slightly loose retainer), unless a replacement couldn't be found. But Gessler has the split collar type for a couple bucks, so...

At least there's no more wondering on my part whether it used the steel retainer or what. Mystery solved.
Thanks TommyK! Here is another view of the cap raised up:


Not sure how lose is too lose but, you are right. For a couple of dollars, why risk it. It is now on the shopping list.




I also tried taking a picture of the meter rods retainer spring to show what condition it was in... and "lost" it in the process. Whoops... I am sure you can see how bad it looks. Just bent every which way.






On the subject of PP, I saw these hash marks on the tube where the PP goes. Do they mean anything?






-------------------




Going back to a previous post...
cobalt327 said:
The jet and rod sizes are stamped into them. The jets have the number on the top surface as you look down at them orientated as if they were installed.

The rods (primary and secondary) have the size stamped onto the rod, you'll need to look for it, possibly use magnification (I do, but my eyes are old).
I tried looking for the stamped numbers and they are hard to see. Taking a picture was even more difficult. It took some heavy editing to bring out the markings. On the jets, the marking is "73". But I can't really make out what it says on the rods, aside from the "3"at the top. "3mm"?






 
#47 ·
The rods look like 38, possibly followed by a "B". The "B" is on the later needles, the earlier needles just had a two digit number on them.

The marks on top the PP cavity is the "staking" that was referred to earlier. It would have helped hold the PP retainer in place.
 
#48 ·
The subject of leaking wells on the Q-jet and what to do about it comes up fairly often.

Shown below are both unused and well seasoned main well "plugs"- like are included in most rebuild kits. The idea is the plug will press against the well bottoms and stop the leakage. Maybe in theory, and maybe for a little while, but it is obviously NOT a permanent fix.

A new plug is on the left, the shriveled up plug on the right was just removed from a Q-jet brought in for a rebuild.



 
#49 · (Edited)
Hey Guys,

Sorry that I haven't posted anything. I was away for a week, spent the last week reading Ruggles' book, and this week I'm laid up in bed with the flu.




cobalt327 said:
The subject of leaking wells on the Q-jet and what to do about it comes up fairly often.
In the book, Cliff says: "Simply dabbing epoxy over the leaking plugs does not work as a long term repair. The epoxy eventually comes loose from the aluminum after many heating-up and cooling-down cycles of the engine." (chapter 5, page 71). I of course, have done just that as a precaution since the wells aren't suspected of leaking.

In addition, the book also mentions a leak test for the plugs: "Apply a soap-and-water mixture over the plugs, then introduce high-pressure compressed air in through the front and rear jet openings in the fuel bowl. A small leak shows a tiny stream of bubbles. Large leaks ... are easy to detect!" (chapter 5, page 71).




I did email Cliff regarding the power piston retainer and he sells it as a part of a rebuild kit. Had I not already bought one, I would have ordered his. I will give him a call to see if he sells it individually (the email made no mention of it). If not, I'll order it from Quadrajetparts.com. In the book, Cliff mentions that the power piston retainer can be held down "with a machinist's ruler during carburetor assembly. (chapter 5, page 84).




While reading the book, I realized one of the things I didn't check for was warpage. I had taken some pictures this past weekend of the carburetor as it sits. It seems like there is a gap between the air horn and the fuel bowl in the rear of the carb. The book says this can be fixed using a belt sander (chapter 4, page 68). Anyone feel this carburetor needs to be sanded or is it negligible?






I also made my way over to the "High Performance Modifications" chapter. My rig is in no way setup for high performance nor do I have any such plans for it. But the book does mention that these mods help "improve performance, driveability and fuel economy." (chapter 6, page 88).

One of the mods mentioned is making sure the throttle plates open up a full 90 degrees. Here are pictures of my carb and the secondaries are opening almost 90 degrees. Sufficient enough?





Another mod listed for throttle plates is drilling small holes in them to add additional air at idle. It is mentioned as an alternative to another mod, which is adding an idle bypass air system. But these are not necessary if the idle bypass air system is already in place. (chapter 6, page 95). I need to check to see if this carb has this system already. If not, I may just drill the plates since adding the idle bypass air system requires alot more work and precision.



**All quotes and cited sections are from Cliff Ruggles' "How to Rebuild and Modify Rochester Quadrajet Carburetors", copyright 2006.
 
#50 ·
lt1silverhawk said:
In the book, Cliff says: "Simply dabbing epoxy over the leaking plugs does not work as a long term repair. The epoxy eventually comes loose from the aluminum after many heating-up and cooling-down cycles of the engine." (chapter 5, page 71).
I've been saying that about using JB Weld forever. Then I hear back, "Ruggles uses Marine Tex epoxy". All I know is, epoxy has failed in the past and I will not use it on my carbs. And I'm glad to hear he seems to think that, too.

It seems like there is a gap between the air horn and the fuel bowl in the rear of the carb. The book says this can be fixed using a belt sander (chapter 4, page 68). Anyone feel this carburetor needs to be sanded or is it negligible?
I cannot see the gap, so I cannot offer an opinion- but if it's significant, you'll want to either replace parts, or... I suppose sand it down. Although I will readily admit to never having done this. That said, it sounds easy, but somehow I doubt it actually IS easy. At least not to get it perfectly smooth and square. But that could be just me.

In any event, this means removing the down tubes from the airhorn (unless, God forbid, you want to sand on the main body :sweat: ). Measure their installed height before removing them, and be careful when you remove them.

I don't know what procedure he uses for this. If you would, post what it is. I would insert a solid piece of wire the same size as the ID of the tubes into them so they could be gripped w/o crushing them.

The inner tubes are bottlenecked on the bottom, so you will want to go in from the top w/the wire "reinforcement", should you try to remove them this way. The inners are also small, it may take a bit from a numbered set to do it, or maybe a cut down pin, etc. Make sure the end of the wire extends out of the tubes, after gripping them for removal the wire will be trapped and you'll want to be able to grip the wire for removal.

All that said- unless there is a gap that will not close up when the screws and bolts are tightened, don't worry about it. They mainly will be warped downward at the corners where the long bolts go through the airhorn down to the intake flange. These get overtightened, and the corners will 'droop'. Unless this is bad, I usually do nothing. I have had to VERY carefully tweak the corners back up some- but this always makes me nervous, cast zinc is brittle.

One of the mods mentioned is making sure the throttle plates open up a full 90 degrees. Here are pictures of my carb and the secondaries are opening almost 90 degrees. Sufficient enough?
You want them to be 90 degrees. Yours aren't. ;)

Another mod listed for throttle plates is drilling small holes in them to add additional air at idle. It is mentioned as an alternative to another mod, which is adding an idle bypass air system.But these are not necessary if the idle bypass air system is already in place. (chapter 6, page 95). I need to check to see if this car has this system already. If not, I may just drill the plates since adding the idle bypass air system requires alot more work and precision.
Do not drill the throttle plates unless as a last resort. If your cam isn't radical (I don't recall any specs on your engine, sorry), this won't be an issue anyway. The more duration/overlap, the more need there is for the bypass air, but there are other ways besides drilling the plates to accomplish this, same as a Holley.

I got a chuckle out of using a machinist rule to hold the PP down in position while reassembling the top of the carb to the body.

My thoughts on this are that it's bad enough already- you have to keep the gasket in position while the return spring of the accelerator pump piston is fighting to extend, plus aligning the down tubes into their proper positions, and at the same time you're aiming the pump through the hole in the airhorn, etc. :smash:

I would do most anything to not add yet another procedure to all that- you'd be running short of hands, I think! lol
 
#51 ·
cobalt327 said:
I've been saying that about using JB Weld forever. Then I hear back, "Ruggles uses Marine Tex epoxy". All I know is, epoxy has failed in the past and I will not use it on my carbs. And I'm glad to hear he seems to think that, too.
TommyK said:
BTW he recommends Devcon Marine-Tex epoxy as the only permanent well plug sealing material he has found.
I list these two quotes only because two different views have been given by two members in this particular thread. Two clear up any confusion, I'll mention what I have found: although Ruggles makes no mention of Marine Tex in the book, he certainly carries it as a part of the Bottom Plug Kit. He also recommends it on his forum. So although he is using epoxy, it is conjunction with the screw-in plugs. :)




------------------




cobalt327 said:
I cannot see the gap, so I cannot offer an opinion- but if it's significant, you'll want to either replace parts, or... I suppose sand it down. Although I will readily admit to never having done this. That said, it sounds easy, but somehow I doubt it actually IS easy. At least not to get it perfectly smooth and square. But that could be just me.

In any event, this means removing the down tubes from the airhorn (unless, God forbid, you want to sand on the main body :sweat: ). Measure their installed height before removing them, and be careful when you remove them.
The gap seems very small, so much so that the camera may not even pick it up. I went back and reread the section on sanding and machining. The airhorn and the base plate can be sanded down "to conform to the main body and prevent leaks at the top gasket." (chapter 4, page 68). The book also mentions that the main body can be machined flat, but it "lowers the power piston the same amount that is taken off the main body and can affect carburetor function." This isn't considered cost-effective unless it is a rare or valuable carburetor. (chapter 4, page 68).




cobalt327 said:
I don't know what procedure he uses for this. If you would, post what it is. I would insert a solid piece of wire the same size as the ID of the tubes into them so they could be gripped w/o crushing them.

The inner tubes are bottlenecked on the bottom, so you will want to go in from the top w/the wire "reinforcement", should you try to remove them this way. The inners are also small, it may take a bit from a numbered set to do it, or maybe a cut down pin, etc. Make sure the end of the wire extends out of the tubes, after gripping them for removal the wire will be trapped and you'll want to be able to grip the wire for removal.
I am confused on this one. Are you taking about the brass tubes in the air horn? I didn't find a procedure for those.




cobalt327 said:
All that said- unless there is a gap that will not close up when the screws and bolts are tightened, don't worry about it. They mainly will be warped downward at the corners where the long bolts go through the airhorn down to the intake flange. These get overtightened, and the corners will 'droop'. Unless this is bad, I usually do nothing. I have had to VERY carefully tweak the corners back up some- but this always makes me nervous, cast zinc is brittle.
To my untrained eyes, I'd say the gap is very minor so I won't worry about it.




---------------




cobalt327 said:
You want them to be 90 degrees. Yours aren't. ;)
Alright, time to do some linkage bendin'.




cobalt327 said:
Do not drill the throttle plates unless as a last resort. If your cam isn't radical (I don't recall any specs on your engine, sorry), this won't be an issue anyway. The more duration/overlap, the more need there is for the bypass air, but there are other ways besides drilling the plates to accomplish this, same as a Holley.
The engine is a bone stock, crate 350, so nothing special or radical here.




cobalt327 said:
I got a chuckle out of using a machinist rule to hold the PP down in position while reassembling the top of the carb to the body.

My thoughts on this are that it's bad enough already- you have to keep the gasket in position while the return spring of the accelerator pump piston is fighting to extend, plus aligning the down tubes into their proper positions, and at the same time you're aiming the pump through the hole in the airhorn, etc. :smash:
I agree. The retainer on my particular carb is no good and I will buy the bushing. But for future reference, I do want to mention that I was able to hold it in place using the gasket between the air horn and the main body. Ruggles seems to be doing the same thing in the picture accompanying the procedure in the book. (chapter 5, page 84).




cobalt327 said:
I would do most anything to not add yet another procedure to all that- you'd be running short of hands, I think! lol
Lol! Point taken! :thumbup:
 
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