viper9403

iTrader: (14)

I'm finishing up the build on my 347/F1 build and am down to ordering pushrods. I have the adjustable pushrod length checker from comp. I have measured at TDC on #1 and have come up with 7.3375 (6.800+10.75X.050) at zero lash. Also this is with stock rockers.

My question is what is the proper preload for these Comp cams 850-16 OE replacement lifters?

Also I measured while the motor was on the stand at TDC. It had been sitting at TDC for about 2 weeks. Now that I think about it, will this sque the measurement being that the lifters might have bled down?

Looking for some different opinions

PREDATOR-Z

They are supposed to bleed down. Thing is did you measure on base circle of cam?
My experience with those 850-16 is preload from .060>.100 I run mine in that margin, I prefer closer to .080
https://ls1tech.com/forums/generatio...r-preload.html

viper9403

iTrader: (14)

Yes this was measured at the base circle.

Here is what Comp recommends but just seems to low?

.030-.040

http://www.compcams.com/Technical/In.../COMP4-116.pdf

viper9403

iTrader: (14)

Hmm I'm suprised no one has any other feedback

Spd-Kilz

iTrader: (35)

Bump for more info on this!

Spd-Kilz

iTrader: (35)

I called Comp Cams today.

He said to run between 0.030 > 0.045. Max preload is 0.060.

vettenuts

iTrader: (4)

Be careful that we aren't talking apples and oranges here. Some provide preload at the rocker bolt, especially on stud mounted. Typically, they provide it as so many turns or thousandths of an inch. If that is where the numbers are specified, you need to multiply by 1.588 to get the proper preload at the pushrod. Since you are measuring with an adjustable pushrod, you need to make sure the preload being provided by COMP is at the lifter plunger and not at the bolt.