Pushrod length question? Help
Thread Starter
Racer
Joined: Apr 2011
Posts: 422
Likes: 1
From: NOVA
Pushrod length question? Help
I want to make sure I'm in the ball park before getting pushrods.
I have LS7 lifters, .045 head gasket, not sure of the base cam height (i wish I would have measured it), milled TF 220 heads with 63cc.
I've measured and with the stock size pushrod and with that size it takes the lash out of the rocker.
I've also measured with the the comp cams checker and pretty much zero lash is taken out between 11 3/4 and 12 turns.
So this leaves me with needing a 7.450 push rod to get 0.50~.065 preload?
From what I've read there is no real answer where to have the preload set on the LS7 lifters. I've read from .030 to .100
It seems like most people are having to get smaller rods (7.3...) and I'm going the opposite way?
Is this sounding right?
I have LS7 lifters, .045 head gasket, not sure of the base cam height (i wish I would have measured it), milled TF 220 heads with 63cc.
I've measured and with the stock size pushrod and with that size it takes the lash out of the rocker.
I've also measured with the the comp cams checker and pretty much zero lash is taken out between 11 3/4 and 12 turns.
So this leaves me with needing a 7.450 push rod to get 0.50~.065 preload?
From what I've read there is no real answer where to have the preload set on the LS7 lifters. I've read from .030 to .100
It seems like most people are having to get smaller rods (7.3...) and I'm going the opposite way?
Is this sounding right?
Racer
Joined: May 2010
Posts: 499
Likes: 5
From: Bensalem PA
Its really going to depend on the base circle of the cam you have in there now. I have a similar setup to you but with a stock gasket, but milled more than yours. My cams base circle is the same as stock and I ended up at 7.350 and it is pretty much dead on. If your base circle is smaller than stock than 7.450 could be correct. 
Thread Starter
Racer
Joined: Apr 2011
Posts: 422
Likes: 1
From: NOVA
What are you running for PL on your lifters? Any sewing machine sounds?
thanks, Tristan
Drifting
Joined: Oct 2004
Posts: 1,790
Likes: 29
From: STL MO
St. Jude Donor '09-'10
I forgot to mention I am also running the LS7 lifters. Are you using stock rockers? I went with Yella Terra's and used the supplied shims (.040) my PL is right inline with your findings. My valvetrain gives off the sewing machine sound most common with the majority.
