850-16 lifter preload??????
3rd Gear
Joined: Aug 2016
Posts: 3
Likes: 0
I realize i am a day late and a dollar short.but i was wondering if Reactor2 was able to quiet his valve train down and if so what was his final lifter preload setting? Mine is loud enough to set knock retard. I have been all over the preload spectrum. I have also spent over $700 dollars in push rods and shims, i am tired of going under the valve covers . any help would be greatly appreciated. I too am running the comp 850-16, mine seems quiet on cold start up but get louder as the temp goes up.
Team Owner
Joined: May 2001
Posts: 87,334
Likes: 1,589
From: Western NY
I realize i am a day late and a dollar short.but i was wondering if Reactor2 was able to quiet his valve train down and if so what was his final lifter preload setting? Mine is loud enough to set knock retard. I have been all over the preload spectrum. I have also spent over $700 dollars in push rods and shims, i am tired of going under the valve covers . any help would be greatly appreciated. I too am running the comp 850-16, mine seems quiet on cold start up but get louder as the temp goes up.
Team Owner
Joined: May 2001
Posts: 87,334
Likes: 1,589
From: Western NY
My only experience with full roller rockers, was with a set of GM Performance Parts "rollers", on a '96 Z/28, also with a set of CompCams 850-75 lifters, and that was a rather noisy set-up. My point, however, is that roller rockers tend to be a little noisy.
3rd Gear
Joined: Aug 2016
Posts: 3
Likes: 0
The reason for the new rockers was because the original ones had 251,000 miles on them and you could feel the up and down movement on the trunion, i could even make them make a clicking noise while in my hand.lol after initial install the new rocker seamed to re leave some of the noise but not enough to stop the knock retard. this weekend on Saturday i ran the truck with .050-.060 inches of preload (seamed quieter but still knock retard) Then on Sunday i went to .075-.080 inches of preload (this was much quieter only retarded on hard acceleration). Now this morning on the way to work it was noisy and setting knock retard repeatedly. i feel like these 850-16 lifters are junk, i have been under the valve covers 10 times trying different preload settings to no avail.
Melting Slicks
Joined: Jun 2002
Posts: 2,591
Likes: 144
From: Mobile al
Never mind.
Put some 03-04 rockers on the car and see what happens. The 03-04 rocker was an upgrade from the older ones.
Have you tried lowering the timing or running race gas to see if it effects the knock retard at all?
Last edited by FASTFATBOY; Aug 16, 2016 at 08:47 AM.
AMP Racing
Joined: Aug 2006
Posts: 10,754
Likes: 589
From: Washington TWP NJ
2023 C5 of the Year Finalist - Modified
2017 C5 of Year Finalist
St. Jude Donor '09-'10-'11-'12
I don't understand why people install aftermarket lifters and rockers when the OEM stuff works great on probably 99% of all street car builds.
This isn't a SBC we're talking about here... GM did a lot of good things when designing the LSx engines. We should take advantage of the millions they spent on R&D.
This isn't a SBC we're talking about here... GM did a lot of good things when designing the LSx engines. We should take advantage of the millions they spent on R&D.
