what length pushrod do i need
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Melting Slicks
Joined: May 2005
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From: Leon Iowa
St. Jude Donor '06-'07-'08-'09
what length pushrod do i need
I'm getting the Comp cams pt number 54-428-11 228/230 571/573 lift. Do I need the stock length or longer? I have the stock rockers
Team Owner
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From: At the beach in little Rhody
They will be noisy with stock length rockers, the base circle of the cam is smaller than stock. Best bet is to measure, but you likely want longer pushrods based on the radius difference between the stock and new cam base circles. The use of stock pushrod is why everyone thinks its normal for a cam to be noisy.
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Melting Slicks
Joined: May 2005
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From: Leon Iowa
St. Jude Donor '06-'07-'08-'09
Originally Posted by vettenuts
They will be noisy with stock length rockers, the base circle of the cam is smaller than stock. Best bet is to measure, but you likely want longer pushrods based on the radius difference between the stock and new cam base circles. The use of stock pushrod is why everyone thinks its normal for a cam to be noisy.
Pro
Joined: Feb 2006
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From: Vancleave Ms.
Originally Posted by mvvette97
How do you measure and decide how much longer you need?
James
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Team Owner
Joined: Mar 1999
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From: At the beach in little Rhody
Pushrod length won't alter the wipe pattern, shimming the rocker base will. To measure the pushrod length, you need an adjustable pushrod. There are several pushrod measurements, but the one that is used to determine length is "gauge length". Gauge length is measured from a point where the ball on the end is 0.140" in diameter. The Comp adjustable pushrod will have a mark on it such that every turn is an increase of 0.050" in pushrod length. You set the cam so that the lifter of cylinder one is on the cam base circle, then install the adjustable pushrod so it is slightly short (you can close it down two turns from your stock length pushrod). Install the pushrod and rocker, torque the rocker to around 10 lb-ft (you don't need to go to the full 22 lb-ft, you are only making sure the rocker is seated). Unscrew the adjustable pushrod until it closes out any clearance (no click click if you move it up and down). Remove the rocker, find out how long the pushrod now is. For stock lifters, you need 0.080" to 0.120" of preload. I think you will find you need 7.425" pushrods. By the way, Comp actually makes LS1 pushrods in 0.025" increments for the LS1 near the stock length for this purpose.
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From: At the beach in little Rhody
Thread Starter
Melting Slicks
Joined: May 2005
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From: Leon Iowa
St. Jude Donor '06-'07-'08-'09
Originally Posted by Mr. Jones
increase the stock pushrod by 1/2 of the base circle difference.
If all other parts are stock and the base circle on the new cam is smaller.
7.425 most likely
If all other parts are stock and the base circle on the new cam is smaller.
7.425 most likely
Le Mans Master
Joined: Aug 2003
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From: American Canyon Lethal Injection
Originally Posted by mvvette97
I'm getting the Comp cams pt number 54-428-11 228/230 571/573 lift. Do I need the stock length or longer? I have the stock rockers
SC5
Team Owner
Joined: Mar 1999
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From: At the beach in little Rhody
Originally Posted by mvvette97
I'm thinking I will go with that. Does comp cams have the size like that or what king do you reccommend?
Le Mans Master
Joined: Dec 2003
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From: Atlanta metro Ga.
Originally Posted by vettenuts
In my previous post, I stated that Comp makes pushrods in 0.025" increments around the stock length and that 7.425 would likely be the right one, but you need to measure, at a minimum the cam base circle.
Go with 7.425's.. May not be perfect BUT it's better than what you'll get with too short stockers and you get a PR upgrade (hardened) in the process.
