Comp Lifter Preload.....
03-08-2006, 10:29 AM
#1
Comp Lifter Preload..... What is the preload for the comp 850-16 OE replacements?
If you follow comps pushrod length "how to" (http://www.compcams.com/information/Products/Pushrods/) it mentions nothing about preload, it just says to measure using the adjustable and order that length. Is this only for solid lifters? There would be quite a big delta between ordering just what is determined using the adjustable pushrod, and ordering what is determined using the adjustable and adding to it the preload like everyone says to do.
If you follow comps pushrod length "how to" (http://www.compcams.com/information/Products/Pushrods/) it mentions nothing about preload, it just says to measure using the adjustable and order that length. Is this only for solid lifters? There would be quite a big delta between ordering just what is determined using the adjustable pushrod, and ordering what is determined using the adjustable and adding to it the preload like everyone says to do.
03-08-2006, 10:32 AM
#2
TECH Regular
iTrader: (1)
Join Date: Nov 2003
Location: Washington Township, NJ
Posts: 490
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by 99whitews6
What is the preload for the comp 850-16 OE replacements?
If you follow comps pushrod length "how to" (http://www.compcams.com/information/Products/Pushrods/) it mentions nothing about preload, it just says to measure using the adjustable and order that length. Is this only for solid lifters? There would be quite a big delta between order just what is determined using the adjustable pushrod and adding to it the preload like everyone says to do.
If you follow comps pushrod length "how to" (http://www.compcams.com/information/Products/Pushrods/) it mentions nothing about preload, it just says to measure using the adjustable and order that length. Is this only for solid lifters? There would be quite a big delta between order just what is determined using the adjustable pushrod and adding to it the preload like everyone says to do.
03-08-2006, 11:22 AM
#4
TECH Regular
iTrader: (1)
Join Date: Nov 2003
Location: Washington Township, NJ
Posts: 490
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by SideStep
Do you have a lot of valve-train noise???
03-08-2006, 11:43 AM
#7
TECH Regular
iTrader: (1)
Join Date: Nov 2003
Location: Washington Township, NJ
Posts: 490
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by SideStep
I was going to ask you.... 
The numbers and procedure I got from a post by Tony Mamo. I know he's played around with these motors a bit so I used his recommendations. .050"-.100". I read that if I wanted it quieter, I could go closer to .100", but I've read that at high rpm's the lifter can pump up some and kill upper end performance. That's why I stayed in the middle. I'm running 7.35" pushrods, because my adjustable pr checker measured 7.28"-7.29". Trending Topics
03-08-2006, 11:46 AM
#8
Originally Posted by 99whitews6
Interesting. One would think that since this is so VITAL to the engine that this would be more of an exact science! 
03-08-2006, 11:50 AM
#9
TECH Regular
iTrader: (1)
Join Date: Nov 2003
Location: Washington Township, NJ
Posts: 490
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by 99whitews6
Interesting. One would think that since this is so VITAL to the engine that this would be more of an exact science!
One other thing I noticed is Comp recommends .020"-.040" of preload and they do it a different way. They say to use a standard PR and set it to 0 lash on the lobe heel. Then to scribe it. Then torque the rocker down and wait 5 minutes for it to bleed and scribe it again. Then take it out and measure the distance between the marks. It should be .030" +- .010". But this isn't for an LS1, and not for 850's.
Many on this forum will tell you anywhere between .060" and .080" cold is the correct preload.
03-08-2006, 12:26 PM
#10
LS1 Tech Veteran
iTrader: (1)
Join Date: Oct 2003
Location: Wichita, Ks
Posts: 1,170
Likes: 0
Received 0 Likes
on
0 Posts
I have the 850-16 lifters and my pre-load is adjusted to .075 - .100". I have valve train noise (like a sewing machine) due to the higher than stock lifts and the extra mechanical mechanism of the roller tip rockers. When I tried .030" pre load, I had significant clicking noises (like mechanical valves that were set too loose). I'm very comfortable with my current pre-load on these factory replacement style lifters. If I had the Pro Magnum Lifters, it would be too much and probably unseat the valves and not allow them to fully close. Comp's instructions are written around the Pro Magnum style lifters in my opinion.
Hope this helps!
Steve
Hope this helps!
Steve
