Push rod length (checker)
Thread Starter
Pro
Joined: Oct 2005
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From: Freeport FL
Push rod length (checker)
Seems that proper pushrod length begins to become a question when you start changing/adding parts. (I am using my old heads, but new block, cam and lifters.)
I was going to use the Crane length checking directions here:
http://www.cranecams.com/?show=techarticle&id=2
But the Comp guy kind of poo-poos that and says to get a pushrod length checker ($18).
My current pushrods measure 7.75", so I am concerned about being out at the edge of their PART #7702-1, 6.800"-7.800" checker.
On that note Comp says 7.200" is nominal for SB Chevy, so that makes me wonder a bit right there....
I was going to use the Crane length checking directions here:
http://www.cranecams.com/?show=techarticle&id=2
But the Comp guy kind of poo-poos that and says to get a pushrod length checker ($18).
My current pushrods measure 7.75", so I am concerned about being out at the edge of their PART #7702-1, 6.800"-7.800" checker.
On that note Comp says 7.200" is nominal for SB Chevy, so that makes me wonder a bit right there....
Race Director
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Posts: 17,676
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Glad to see you are doing things right, just get the Crane adjustable pushrod 7.5" to 8.7"
Comp tech has been smoking rope
http://www.cranecams.com/?show=brows...Number=99726-2
Comp tech has been smoking rope
http://www.cranecams.com/?show=brows...Number=99726-2
Thread Starter
Pro
Joined: Oct 2005
Posts: 541
Likes: 1
From: Freeport FL
Thanks!
I've no real experience here, and do not want to crater my new engine over some stupid thing like this. When I put the hammer down on this thing, (and I will, because there is nothing like that supercharger howl at 6K RPM
) I want to do it knowing that I've done everything I can to keep from spraying engine parts all over the roadway.
I've no real experience here, and do not want to crater my new engine over some stupid thing like this. When I put the hammer down on this thing, (and I will, because there is nothing like that supercharger howl at 6K RPM
) I want to do it knowing that I've done everything I can to keep from spraying engine parts all over the roadway.
Pro
Joined: Jul 2008
Posts: 699
Likes: 3
From: Millersville, MD
When I did my top-end build, my original pushrod length was 7.80 for a 79 L-48. I bought the pushrod checker tool for peace of mind to just be sure what I was installing was correct. Turns out 7.80 was the way to go for me. Be sure to get one piece pushrods.
Drifting
Joined: Jan 2006
Posts: 1,832
Likes: 38
From: Cedar,BC
Depends on what the old ones are,and their condition.I don't know what you have in your shop,you could make up your own adjustable pushrod with an old pushrod,fine thread bolt and nuts if you have some extra stuff and a welder lying around.
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Thread Starter
Pro
Joined: Oct 2005
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From: Freeport FL
Given the above information then, it would appear that my old pushrods would not be suitable for anything besides welding together into stick figures
I guess I will have to get the 6.8-7.8 checker then......
Last edited by Droshki; Dec 17, 2008 at 05:32 PM.
Race Director
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Did I forget to mention that I am changing from a older flat tappet block to a newer factory roller cam block?
Given the above information then, it would appear that my old pushrods would not be suitable for anything besides welding together into stick figures
I guess I will have to get the 6.8-7.8 checker then......
Given the above information then, it would appear that my old pushrods would not be suitable for anything besides welding together into stick figures
I guess I will have to get the 6.8-7.8 checker then......
Thread Starter
Pro
Joined: Oct 2005
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From: Freeport FL
Which leads me to believe that things will be significantly different with my new roller cam than my old flat tappet cam?
Race Director
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Pushrods on my 406ci ( oem GM block gen 1 ) with a retro roller was 7.9" , my 427ci with a retro roller ( Motown block ) is 8", it's your money
Le Mans Master
Joined: Apr 2006
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Catalog I have lists stock flat tappit length pushrods at 7.80
A late model 350 ( I assume this is the last roller cam engine before LS1
showed up) 7.20
LS1 stock length 7.40
This is out of a manley catalog I have from 2006
A late model 350 ( I assume this is the last roller cam engine before LS1
showed up) 7.20
LS1 stock length 7.40
This is out of a manley catalog I have from 2006
Thread Starter
Pro
Joined: Oct 2005
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From: Freeport FL
Again....
My old flat tappet engine...
My new roller tappet engine....
So I need to get a checker sized for the new roller engine, not the old flat tappet engine.
My old flat tappet engine...
My new roller tappet engine....
So I need to get a checker sized for the new roller engine, not the old flat tappet engine.
Le Mans Master
Joined: Apr 2006
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Motor head is convinced you need a longer starting set I know he has used a couple of solid rollers. Sounds like he had one hydrauilc retro roller hydraulic roller cam I don't know about before he went into the real world went solid.
It sounds like the comp guy might have thought you were talking
about a later hydraulic roller cam gen two engine when he said 7.2
length. Jakson builds engines for a living he does not like
PMs but he answers e-mails. He may have used every brand retro hydraulic roller known to man by now.
It seems like just looking at my catalog you would need a shorter checking set but don't just oder one e-mail jackson or call more then one cam company.
Last edited by Little Mouse; Dec 18, 2008 at 01:55 PM.
Race Director
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
As far as I know the shorter 7.2" length is for Gen 2 factory roller block. Stock Gen 1 flat tappet is 7.8. Now you get into the retro fit roller stuff and it didn't change all that much for me.
I only built two roller motors and both were solid rollers and the pushrod length for both were in the 7.9-8" range. So as far as retro hydraulic rollers go I don't really know for sure but it wouldn't surprise me if they were in the same ballpark. These are Comp lifters I am talking about here. So I kinda got mixed up with what setup the original poster has, but like I said It wouldn't surprise me to see the pushrod length in the 7.8" or greater range
I only built two roller motors and both were solid rollers and the pushrod length for both were in the 7.9-8" range. So as far as retro hydraulic rollers go I don't really know for sure but it wouldn't surprise me if they were in the same ballpark. These are Comp lifters I am talking about here. So I kinda got mixed up with what setup the original poster has, but like I said It wouldn't surprise me to see the pushrod length in the 7.8" or greater range
Last edited by MotorHead; Dec 18, 2008 at 04:58 PM.
Le Mans Master
Joined: Apr 2006
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Jackson has 7.2 for a factory roller, 7.3 for retro I assume he knows the poster is going to use a retro hydraulic roller.
There must be a considerable difference between solid rollers
and gen 1 retro hydraulic roller in push rod lengths.
There must be a considerable difference between solid rollers
and gen 1 retro hydraulic roller in push rod lengths.