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  #61 (permalink)  
Old 09-24-2012, 06:41 PM
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I measure how far the valve lifts off the seat, in several ways at the rocker tip or at the valve face or wherever convenient particular to the build and eng. design and model

As an example: I guess everyone measures a flat head V8 or L Head valve lift at the stem with a dial indicator during assembly with the heads off ! I do it at the face of the valve as I turn the engine over its easier




to those that are interested I'll post this unuseful info to some people and useful to some others:

http://www.hotrodders.com/forum/atta...1&d=1348526074


Mouse motor naturally aspirated as an example.

Dual grind cam:
on a cam with extended exhaust timing 1.6 ratio rockers on the exhaust are detrimental to performance like a cam with 2 durations and lifts the larger on the exhaust lobe stay with the 1.5s, but on the intake the 1.6s may help power.

But on a straight ground cam same duration and lift on exhaust and intake! The 1.6 ratio rocker may help a lot on the exhaust valves not the intakes! The 1.6 rocker when opening The smaller exhaust valve will open a little more at full lift increasing the off seat gap (making it larger) so the crank isn't pushing as hard on the rod and piston to push the spent exhaust out of the smaller gap between the valve and seat thus relieving back pressure creating a little more torque, Thats a simple explanation. With open headers scavenging the increase is greater like at the drag strip!!! On the street with restrictive exhaust it will probably show no gains at all!!

With high compression engines the intake charge as the piston goes down creates a lot less drag but when the charge ignites it expands and the higher the compression the more it expands and more heat is created and more expansion, so the crank works harder on the exhaust stroke to push the hot expanded gases out, then the intake stroke pulling a cool charge in. It also helps get a cleaner intake charge in because the cylinder has been evacuated of spent gases more effectively!!

Dont just throw on larger ratio rockers on any cam grinds, you may actually kill power!!! YOU HAVE TO TEST!! Many cam company's sell adjustable rockers one rocker can be used for 1.5 or 1.6 ratios by a simple adjustment. run a few passes with 1.5s on all valves, then put the 1.6 ratio on your intakes (you can buy 8 rockers and put them on the intakes or buy a whole set or borrow some) run a few pass's and see if it runs stronger. then put the 1.5s back on the intakes and the 1.6s on the exhaust run a few pass's and see if its running stronger! or all 1.6s on all valves but Ive never had to do that.

Its a lot of work and its better to use a dino and easier but expensive.


You can have cams ground to the specs you need to do the same thing but how many cams would you go through before you found the right one!!!! for your set up! That's why company's came out with cheep different ratio rockers as an alternative.


Jester

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  #62 (permalink)  
Old 09-24-2012, 06:47 PM
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ap72,where did I say tune a carb for 12:1 at part throttle? I was comparing a 13:1 street car Vs a 12:1 race car tune,and exhaust makes a big difference. My BB Camaro picked up 3/10s with out the mufflers.Maybe it was the weight?lol.
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  #63 (permalink)  
Old 09-24-2012, 06:48 PM
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Quote:
Originally Posted by Daubers View Post
Looks like ill be trading for a 650 double pumper

Now since i have everyone here that knows my setup, should I use the current victor jr intake or swap for an edelbrock performer rpm ( already have one )?


You made a good choice swapping carbs I like a single plane manifold. on most performance builds and dual plane on streeters used more for mileage and rides through the country or as winter cold climate vehicles .

good luck post again when you find what you want!

Jester it was fun on this post I was cracking up at some of the stuff posted
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  #64 (permalink)  
Old 09-24-2012, 06:51 PM
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Quote:
Originally Posted by vinniekq2 View Post
ap72,where did I say tune a carb for 12:1 at part throttle? I was comparing a 13:1 street car Vs a 12:1 race car tune,and exhaust makes a big difference. My BB Camaro picked up 3/10s with out the mufflers.Maybe it was the weight?lol.
I agree. LOL

Jester
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  #65 (permalink)  
Old 09-24-2012, 06:55 PM
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Quote:
Originally Posted by lmsport View Post
Street cars absolutely need PV's as do most race cars.
You wouldnt take the mixture rods out of a Qjet or a Carter would you?
Many Q-jets- both originally feedback carbs as well as non feedback carbs- have been successfully modified for competition by removing the metering rods and rejetting to compensate for the rods. This is actually a relatively common thing. You wouldn't do this for a street only deal obviously.
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  #66 (permalink)  
Old 09-24-2012, 06:56 PM
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Painted jester,Im glad you enjoyed the thread.Hope I dont look too foolish and just make you chuckle a little,,,
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  #67 (permalink)  
Old 09-24-2012, 07:09 PM
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Quote:
Originally Posted by Daubers View Post
Looks like ill be trading for a 650 double pumper

Now since i have everyone here that knows my setup, should I use the current victor jr intake or swap for an edelbrock performer rpm ( already have one )?
I'd use the dual plane, hands down. It will give you more power under the curve than the single plane. The single plane might peak a bit better (or not)- but you might be surprised at how well the RPM works.

I'm sure you know the deal w/the difference between the two designs; the RPM will have a broader powerband in almost every case where a streetable cam is used. This is especially true on a street driven vehicle where peak hp is not the most important thing. Not to mention the fact that you're running fuelie heads that don't have a very big intake port volume, even if ported. In my opinion there's no question as to which will work better on the street.

In the video comparison below, the heads are bigger than yours, as is the cam. Yet the results support my position, I believe. The results on your engine should be even more biased towards the dual plane.

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  #68 (permalink)  
Old 09-24-2012, 07:11 PM
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I think you know your stuff I Wasnt laughing at you I guarantee it !!! Your posts were right on!! And Cobalt just chimed in With what we both new from the start But didnt post because we were both laughing

Thanks for posting that Cobalt

Vinnie and I pmed and decided not to make waves and getting called stupid!!!! Vinney did mention you could remove them on a carter!!! We did that a lot years ago!

Jester
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  #69 (permalink)  
Old 09-24-2012, 07:40 PM
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re video,his lathe sure looks like a milling machine to me?,lol,,,
I would like to see that test again using 1 3/4 headers?At or around 500 HP I think the headers would make a change,for racing,not the street so much.
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  #70 (permalink)  
Old 09-24-2012, 07:43 PM
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Quote:
Originally Posted by vinniekq2 View Post
re video,his lathe sure looks like a milling machine to me?,lol,,,
I would like to see that test again using 1 3/4 headers?At or around 500 HP I think the headers would make a change,for racing,not the street so much.
I agree. Most times the dyno headers tend to be on the big side, but not in this case...
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  #71 (permalink)  
Old 09-24-2012, 07:44 PM
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Quote:
Originally Posted by painted jester View Post
I measure how far the valve lifts off the seat, in several ways at the rocker tip or at the valve face or wherever convenient particular to the build and eng. design and model

As an example: I guess everyone measures a flat head V8 or L Head valve lift at the stem with a dial indicator during assembly with the heads off ! I do it at the face of the valve as I turn the engine over its easier




to those that are interested I'll post this unuseful info to some people and useful to some others:

http://www.hotrodders.com/forum/atta...1&d=1348526074


Mouse motor naturally aspirated as an example.

Dual grind cam:
on a cam with extended exhaust timing 1.6 ratio rockers on the exhaust are detrimental to performance like a cam with 2 durations and lifts the larger on the exhaust lobe stay with the 1.5s, but on the intake the 1.6s may help power.

But on a straight ground cam same duration and lift on exhaust and intake! The 1.6 ratio rocker may help a lot on the exhaust valves not the intakes! The 1.6 rocker when opening The smaller exhaust valve will open a little more at full lift increasing the off seat gap (making it larger) so the crank isn't pushing as hard on the rod and piston to push the spent exhaust out of the smaller gap between the valve and seat thus relieving back pressure creating a little more torque, Thats a simple explanation. With open headers scavenging the increase is greater like at the drag strip!!! On the street with restrictive exhaust it will probably show no gains at all!!

With high compression engines the intake charge as the piston goes down creates a lot less drag but when the charge ignites it expands and the higher the compression the more it expands and more heat is created and more expansion, so the crank works harder on the exhaust stroke to push the hot expanded gases out, then the intake stroke pulling a cool charge in. It also helps get a cleaner intake charge in because the cylinder has been evacuated of spent gases more effectively!!

Dont just throw on larger ratio rockers on any cam grinds, you may actually kill power!!! YOU HAVE TO TEST!! Many cam company's sell adjustable rockers one rocker can be used for 1.5 or 1.6 ratios by a simple adjustment. run a few passes with 1.5s on all valves, then put the 1.6 ratio on your intakes (you can buy 8 rockers and put them on the intakes or buy a whole set or borrow some) run a few pass's and see if it runs stronger. then put the 1.5s back on the intakes and the 1.6s on the exhaust run a few pass's and see if its running stronger! or all 1.6s on all valves but Ive never had to do that.

Its a lot of work and its better to use a dino and easier but expensive.


You can have cams ground to the specs you need to do the same thing but how many cams would you go through before you found the right one!!!! for your set up! That's why company's came out with cheep different ratio rockers as an alternative.


Jester
http://www.hotrodders.com/forum/atta...1&d=1348537431

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  #72 (permalink)  
Old 09-24-2012, 07:56 PM
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Great video, thanks cobalt. Performer rpm w 1" spacer it is!
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  #73 (permalink)  
Old 09-24-2012, 08:24 PM
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Cobalt; those air gap intakes in the cold north cause the carbs to frost and freeze up Ive installed quite a few when every one wanted one! and only a few people complained but they started to frost the carbs about 40 degrees (well actually the air rushing through the cab is what did it!) There's no heat under the carb from the exhaust passage its been eliminated! My fix on one was a spacer under the carb that water goes through like the old fords had< the heater hose runs through it and a vacuum shut off from a 76 vette in line.> That kept em warm but didn't cook em!!!! and you can close the water controle in the summer with the vacuum control! I thought I had a brain stom when I came up with that!!

When its cold and humid they frost quick with a cold air package on em LOL

Now that I put it on line someone will market it and get rich But Fords probably still holds the patent pretty well covered! Hell I got the idea from working at fords!!!!

The performers a good intake!! For the north.

Jester
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  #74 (permalink)  
Old 09-24-2012, 08:43 PM
How fast is fast enough?
 
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Quote:
Originally Posted by vinniekq2 View Post
ap72,where did I say tune a carb for 12:1 at part throttle? I was comparing a 13:1 street car Vs a 12:1 race car tune,and exhaust makes a big difference. My BB Camaro picked up 3/10s with out the mufflers.Maybe it was the weight?lol.
or the wrong mufflers

There is NO reason to run a different WOT AFR on a street engine vs a drag engine, max power is max power, it doesn't matter if there is a pot hole or not.
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  #75 (permalink)  
Old 09-24-2012, 08:50 PM
How fast is fast enough?
 
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Quote:
Originally Posted by Daubers View Post
Looks like ill be trading for a 650 double pumper

Now since i have everyone here that knows my setup, should I use the current victor jr intake or swap for an edelbrock performer rpm ( already have one )?
I'd forget the 650 and just send your carb to a very reputable shop to be rebuilt and given a baseline tune. It'll be about the same cost but you end up with a better carb.
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