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Really need to get my daily driver

2197 Views 79 Replies 9 Participants Last post by  KAMjenII
1984 Monte Carlo Base Converted SS Body

305 LG4 Motor with 305 H.O. Heads
Edelbrock Performer EPS Intake Manifold

Edelbrock 1902 AVS2 Series 500cfm Carburetor (Manual Choke)

De-smogged/Non-Emission/Non-Computer Setup.

I bought this car a year ago, replaced things, and as I was replacing the distributor with the distributor removed, I overturned the engine...have had idle and acceleration problems ever since.

Car History: I was told at the time of purchase that this was an SS Monte Carlo...I was also told that the motor was a rebuilt 350 with 46,000 miles on it...I didn't know much about the SS Monte Carlo, it just looked like one to me.

Since this was to be my daily driver, I wanted to buy new parts and replace the old parts and jumped into Monte Carlo SS Facebook groups and online forums to learn how to replace everything.

First thing I learned is that this wasn't an SS Monte Carlo by looking up the VIN # and other visual things like black trim instead of chrome trim...the original V6 motor, computer, and emissions were ripped out and replaced with this "Rebuilt 350 with 46,000 miles on it".

After looking up the engine block and head casting #'s, I learned that this motor is actually an 1983-1984 305 with 305 H.O. heads...

It had an Edelbrock Victor Jr. Single Plane Intake and an Edelbrock Performance Series 650cfm electric choke carburetor...I was told both were too big for my 305 motor, and to swap them with a smaller rpm range and cfm rating. I swapped with what I have now (listed in the beginning) and things where better but my timing seemed incorrect and after spending months of playing with it, I decided to replace and inspect the timing chain set. I could never achieve 600 rpm to correctly set factory timing settings.

First thing i found was the Tach was set for a 4 cylinder engine, instead of an 8 cylinder engine, I set it for 8 cylinder. I replaced the timing chain set with a Cloys double roller and installed it correctly. While I was that far into the motor, I wanted to pull the camshaft so I knew exactly what it was I was working with, but nobody could seem to guide me so I slapped the timing chain and cover on without checking it out. I have no idea what the camshaft specs are.

Second thing I found wrong was the timing tab on the timing cover. With the prior 2 o'clock TDC position timing tab fully exposed, I used a spark plug stop tool/TDC finder to find the motors true TDC...seeing how everything else was wrong...the timing marked showed TDC was actually 12 o'clock, not 2 o'clock...so I swapped it with the correct timing tab.

The 3rd thing was the harmonic balancer was the 8" instead of the factory 6.75", so I swapped it for a 6.75".

The carburetor distributor vacuum advance was also plugged up as an emissions setup, so I plugged it up as non-emissions due to my de-smogged/non-emissions setup.

The engine seemed to run and idle a lot better.

Next was my fuel pressure...I was running an electric fuel pump but after it failed I swapped it out for a mechanical fuel pump. The new mechanical fuel pump was pushing 9psi of fuel pressure, so I installed a fuel pressure regulator and the current pressure is at 6, but can be adjusted to 4psi.
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Discussion Starter · #21 · (Edited)
If your reading 24 with the vacuum advance out of the system it would be a strong indicator that you have the distributor a tooth off
OK, one thing I thought that looked odd and could be the issue to my problem is I'm off a tooth....during distributor drop in, my pointer wasn't exactly pointing at the drivers side front intake bolt, it pointed more between cylinder 1 and cylinder 2.

I've literally dropped this distributor flush with the engine all the way clockwise and the only two directions I can get it in as close to where it's supposed to be are these two positions...
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From what I'm seeing in multiple YouTube videos is the pointer should be pointing at the first intake manifold bolt on the drivers side, all of them used a long screwdriver to rotate the oil pump shaft...neither of these pictures of mine are pointing there and these are the only two settings I can get near it...
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Is my pictures considered "off a tooth or two" ? Should I grab a long screwdriver and rotate the oil pump shaft to achieve the correct position ?

The second picture is what I'm driving with now...
 

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As long as you've been setting the final timing check with the timing light....you cannot be a "tooth or two off".

That "tooth or two off" stuff is just for preliminary installation of the distributor for initial engine fire up....once it is up and running and checked with a timing light, that factor or "tooth or two off" no longer applies....since the timing light is the final authority on the matter.


There is absolutely zero requirement for the rotor to point at the "front cylinder intake bolt"....that's a bunch of hogwash from idiot mechanics.....GM points it there for ease of installation on the assembly line so the installer's job is always the same, but that's it.
 

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I've played with this numerous of times...the only other setting close to that is this... View attachment 624460
Last picture in your this post has the vacuum advance can in the correct position but tge rotor pointing at cylinder at cylinder number 8 terminal. This is OK if your put the number 1 plug wire into this terminal and then proceed with the firing order from there.

The easiest way to rotate the pump drive is to buy a prelube driver and use it to turn the pump drive. This lets you index the top of the shaft to get a visual on where the pump drive mortis is. The spiral gear rotation of distributor gear into cam is always a headache because the gear is rotating as it drops. There are 13 teeth on the distributor gear which is 27.7 degrees per tooth that times 2 makes being off a tooth an error at the crank’s timing marks of 55.4 degrees rounded to one decimal point. At the cap there are 45 degrees between terminals which times 2 at the crankshaft makes 90 degrees between cylinder firings. 90 degrees comes from 720 degrees in a full 4 piston cycles divided by 8 cylinders makes 90 degrees of crank rotation which is 45 degrees camshaft and distributor that are running at 1/2 rotation for one crankshaft rotation. So being off a tooth on the distributor to cam gear’s mate is a big deal. But like I said you can adjust the terminal pin out to match where the rotor sits to the closest available terminal. The factory position of vacuum advance canister and number one terminal are only references to get space to move the distributor for setting base timing without getting jammed with the intake manifold. The terminal for number 1 pointing at number one is just a reference point you can start number one from what ever terminal tge rotor is pointing at and just pin the rest of the firing order clockwise looking down on the cap from there.

My own mess up the night I stuffed a new trans against Frankenmouse I lost count of my crank rotations while torquing the converter to flex plate bolts. Turned out I was 180 out which cylinder 6 ready to fire. I aligned the distributor to number 1 firing getting a blast through the injector throttle when cranking. I went ya know it’s 3 in the morning I not going to pull the distributor and go through the drill to back to it and the rotor aligned with number one. so I pulled the plug wires out and popped number one into the number six terminal than went around the firing order from there. Cranked it up set the timing adjusted my TV pressures took a test drive. Got home took a shower changed into business clothes and went to work. Left the distributor like that for a few months till I had time to get back to it.

The best way to do the set up after you first get it and then at some future date R&R the distributor is in the attached vid link.


Bogie
 

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Discussion Starter · #26 · (Edited)
Last picture in your this post has the vacuum advance can in the correct position but tge rotor pointing at cylinder at cylinder number 8 terminal. This is OK if your put the number 1 plug wire into this terminal and then proceed with the firing order from there.
There is absolutely zero requirement for the rotor to point at the "front cylinder intake bolt"....that's a bunch of hogwash from idiot mechanics
OK then, no need to R&R the distributor...that isn't causing my issues then...

I'm pretty sure my issue is either timing or vacuum leak...but I'm thinking more of timing...

I think my timing tab and balancer are mismatched, causing me not being able to set the timing right...

I started another thread yesterday discussing the 3 different timing tab and harmonic balancer matchups in GM production history from 1969-1995...just my luck too, in 1984 they transitioned from 2:00 timing tab to the 12:00 timing tab...everything from 1985-1995 was 12:00 and everything prior to that was 2:00 timing tab...and depending where your OEM balancer timing groove was before the keyway, 10° or 40°, depended which timing tab it came with.

Monte Carlos factory came with 6.75" balancers and there are two different Dorman 6.75" balancers that have 3 GM interchange OEM part numbers:

#1. 594-009 Dorman Harmonic Balancer - OEM interchange part numbers "C312304, 66509" - Model and years - 79,81-88 Monte Carlo Base and 83-88 Monte Carlo SS.

# 2. 594-010 Dorman Harmonic Balancer - OEM interchange part number "C312302" - Model and years - 70-74 Monte Carlo Base.

Looks like mine should be the 594-009 Dorman or GM C312304, 66509 Harmonic Balancer - 79,81-88 Monte Carlo Base and 83-88 Monte Carlo SS.
 

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my throttle response at take off is late and the engine "skips" as if it wants to stall if I put the gas pedal to the floor.

I'm told I'm too lean and to check for vacuum leaks.
[/QUOTE]

This sounds like an accelerator pump causing a lean condition, not necessarily a vacuum leak. A weak pump shot could be to blame.
Are you still having this particular problem when you accelerate fully?
 

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Discussion Starter · #28 ·
Looks like mine should be the 594-009 Dorman or GM C312304, 66509 Harmonic Balancer - 79,81-88 Monte Carlo Base and 83-88 Monte Carlo SS.
What I have is not Dorman branded. It's an "ATP Automotive Graywerks 102069" and here is a picture of it and the distance between the timing groove and keyway outlined in blue. Is this 10° or 40° of distance from the timing groove to the keyway ?
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Discussion Starter · #30 ·
What I have is not Dorman branded. It's an "ATP Automotive Graywerks 102069" and here is a picture of it and the distance between the timing groove and keyway outlined in blue. Is this 10° or 40° of distance from the timing groove to the keyway ? View attachment 624466
Here is the 1970 Chevrolet Monte Carlo 6.75" harmonic balancer by the same brand, ATP Automotive Graywerks 102075 Engine Harmonic Balancer
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This one looks to be 10° before the keyway, so the one I has a 40° distance before the keyway, meaning I should have a 2:00 timing tab, not the 12:00 timing tab I have...

But with the piston stop tool, the mark showed 12:00...🤔...however, from what I'm learning, what matters is the timing tab matching the balancer...which in my case, would be the 2:00 timing tab ?

Hopefully someone is following me here lol
 

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Tynan, you found top dead center withe tdc tool. Did you mark that on your balancer and then set timeing off that mark? Even without a time light you should be able to adjust your distributor close enough to get the engine to run decently. I still believe your problem is carberation.
 

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Discussion Starter · #33 ·
This sounds like an accelerator pump causing a lean condition, not necessarily a vacuum leak. A weak pump shot could be to blame.
Are you still having this particular problem when you accelerate fully?
Just at take off and through 1st gear, 2nd-3rd gear are good I believe. Downshifting seems slow or late, I could be wrong.

If I floor it from a dead stop, it skips, backfires, and stalls if I leave the gas pedal floored, I have to ease way out of a complete stop to take off.
 

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Discussion Starter · #35 ·
Grumpy says.
If your balancer is 40 degrees, and after the year 1984, it looks like you need the 12:00 tab.
I have a 12:00 timing tab now, so we know there isn't a mixmatch.
Tynan, you found top dead center withe tdc tool. Did you mark that on your balancer and then set timeing off that mark?
With the new 6.75" balancer and using the TDC tool, the groove already on the balancer lines up to 12:00, which is what would be directly between the two lines I made using the TDC tool.

I already had taken off the 8" balancer and replaced it when I bought the TDC tool and discovered the 12:00 thing.
 

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Discussion Starter · #36 ·
Even without a time light you should be able to adjust your distributor close enough to get the engine to run decently. I still believe your problem is carberation.
Yea, I just bought this carburetor brand new less than 4 months ago. I had to use ethanol gas once as an emergency, and I've read about not using ethanol with these carbs.
 

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Discussion Starter · #37 ·
Even without a time light you should be able to adjust your distributor close enough to get the engine to run decently. I still believe your problem is carberation.
Yea, I just bought this carburetor brand new less than 4 months ago.
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I had to use ethanol gas once as an emergency, and I've read about not using ethanol with these carbs.


This sounds like an accelerator pump causing a lean condition, not necessarily a vacuum leak. A weak pump shot could be to blame.
I've been told that also, and that the ethanol gas damages the rubber on the accelerator pump specifically...that's the only thing I can think of because the carb is so new...but man, I rebuilt my Performer Series, I can't afford an AVS2 rebuild kit for awhile but removing the top piece allows me to replace the accelerator pump without a rebuild kit, I'm sure like the Performer Series.

Damn sure can't afford a new carburetor...
 

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Ethanol laced fuel up to E10 will have no effect on operating performance for carbs jetted for gasoline. The talk about rubber deterioration is some where between information of a problem 40 years ago and and an old wives tale.

You need to find true TDC especially since there is good ground to suspect this engine in part or in total is not native to the car. A way to check the block at least is on the right side of the engine as you see it seated behind tge steering wheel which puts it on your left as you peer in over the radiator is a pad just above and behind where the coolant pump mounts on that side. If the block has not been decked there will be two symbolic rows of information stamped on that pad. The furthest back row of data and the shortest length is the engine assembly plant data this can be decoded on line or send it here and we can do it for you. The code will start with the plant that put the pieces together making the engine, next is a date code for when that happened, last is a two or three usually letter code of the final vehicle it is configured for. The front most code will be a partial VIN number of the vehicle it was installed into by the factory. If the block is native to your vehicle part of its VIN code on the vehicle i.d. plate will be identical if this doesn’t match the engine block at least is not original. This is what is meant by “numbers matching” in the automotive collector world.

You really need to get to knowing where TDC is, probably the easiest way to pull this off is to buy both a timing tape for your damper diameter and a positive piston stop. Then with a length of stiff wire such as that found from a coat hanger fashion a pointer that is easy to see and overhangs closely to the timing tape on the damper. This process is easier to do with the sparking bolts out as it makes the engine easier to rotate. With the piston stop installed in the number one cylinder (left side front as seated behind the steering wheel for this motor). Using a wrench on the damper bolt rotate in the running clockwise direction; when stopped note the pointer degrees. Now rotate the crank backwards till it is stopped again and note the degrees. TDC is exactly half way between your noted stopped positions. Remove the positive stop and rotate the crank till that calculated mid point matches you wire pointer. The question to be answered is at this point where does the damper’s engraved timing mark align to the timing tab? If you have damper mark to timing tab as zero to zero you’re good if not the damper and tab are not a matched pair needing some sort of rectification. It is not necessary for this test to align the zero mark of the timing tape with that of the damper we‘re just determining the positions of tape to wire pointer and that of the damper engraving to the timing tab as relative to each other for math and observational purposes.

Your miss firing on throttle opening can also be bad performing spark plugs. Check to see if they are dirty on the insulator and have a gap not over .035 inch. These peanut plugs are intolerant of dirty insulators and once fouled need replacement.

Bogie
 

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I would not run ethanol gas in any carbureted application.
I just recently found out that a pump marked non-ethanol can actually have up to 9% ethanol in it. the only affordable gas I have found that is guaranteed non-ethanol is airplane gas.
 

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I would not run ethanol gas in any carbureted application.
I just recently found out that a pump marked non-ethanol can actually have up to 9% ethanol in it. the only affordable gas I have found that is guaranteed non-ethanol is airplane gas.
Here in the northwest corner of what passes these days for a nation we’ve been on E10 for about 35 years. In that time I have never had a problem nor seen a problem that I can say is a fault of E10. Maybe our regional refinery in Anacortes is unusually good at blending or maybe it’s Alaskan crude as a foundation or they use better booze in their blend but whatever the cause I have yet to see a part failure that I could conclusively grunt and say alcohol did it.

The only problem with modern fuels is they are blended to evaporate quicker because of the needs of fuel injection having to do most of the AFR mixing in the cylinder. So since the fuel once into and past the pump is under pressure a lower vapor point isn’t a problem as it is just sitting in a hot carburetor at atmospheric. I handle this with a switch on the fuel pump that being an in tank electric so like aircraft I can shut it down by killing the fuel pump and letting the engine burn through the float bowl fuel, which I do if the thing isn’t going to be used daily. I shut down my Harley’s the same way by just turning off the fuel valve a letting the engine run the carb’s dry.

Couple years ago on my Heritage I was riding to a friends house in Yakima and decided to take the scenic route over the back side of Mt Rainer rather the the Interstates. When on my hard tail which only has a 3.1 gallon king tank on it I have to stop at Greenwater which is the last fuel stop for the next hundred miles and from my house to Greeneater burns out 70 miles of fuel. As a habit I stop there on the Heritage just to cover my contingencies but it’s 5 gallon tank isn’t usually a problem. This last trip the only fuel they had at Greenwater Chevon was leaded so I just decided to press on rather than contaminate the Harley with leaded fuel which has never been in that tank nor in the tank of the hard tail.

Bogie
 
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