LS1 lifter preload

Reply Subscribe

Thread Tools

Search this Thread

Feb 10, 2015 | 01:14 PM

Jarren_b

Thread Starter

TECH Regular

Joined: Apr 2011

Posts: 403

Likes: 0

LS1 lifter preload

I know there are multiple threads on this but im having a hard time finding a definite answer.

I have a BTR stage 2 NA cam. specs are 227/234 .614"/.576" 113+2

When I first installed it my valvetrain noise was insane with 7.400 pushrods

I got rid of those and went to 7.425 and it made it much quieter. I still have valvetrain noise especially under light load from 1000-2000 rpm. I have longtubes so it makes it worse

Basically im questioning if my 7.425 pushrods are also too short. I bought a pushrod length checker that ill be using in a few days so I have a few questions

Do 97 Ls1's have a thicker head gasket?

Will I need two different length pushrods from the difference from my intake and exhaust lift?

what is the best preload for stock LS1 lifters?

Does the trunion upgrade help with noise?

Thanks in advance for the help

If Brian tooley racing wanted to chime in that would be great!

Feb 10, 2015 | 01:30 PM

Jarren_b

Thread Starter

TECH Regular

Joined: Apr 2011

Posts: 403

Likes: 0

Or how could I find out Pushrod length with the base circle measurement of the cam?

Unfortunately I dont know the base circle size

Feb 10, 2015 | 03:25 PM

Jarren_b

Thread Starter

TECH Regular

Joined: Apr 2011

Posts: 403

Likes: 0

Based on my research it seems that this formula is correct. someone let me know if not.

So stock Ls1 cam is

39.37/2=19368 mm or (.775")

My cam is 35.8902/2=17.945mm or (.706")

.775-.706 is .069 smaller

So to stay within stock preload settings I would need atleast a 7.450 pushrod or higher? Technically 7.465?

Currently I have 7.425. Which would explain the noise.

Feb 11, 2015 | 12:59 PM

BlwnLs1GTO

TECH Enthusiast

iTrader: (12)

Joined: Mar 2006

Posts: 577

Likes: 8

I have 8 brand new Comp Magnum PR's in a 7.450. .080" wall that I cant use for my build. 35 bucks shipped if you want them. LMK.
Sorry I'm not adding any tech info, but this was a perfect time to help you and me out.

Feb 11, 2015 | 01:32 PM

svede1212

12 Second Club

iTrader: (3)

Joined: Apr 2004

Posts: 1,512

Likes: 3

From: Grand Rapids, Michigan

Measure. Don't calculate or guess or go by sound. You want .050-.060

Feb 11, 2015 | 01:40 PM

WE TODD DID

TECH Fanatic

iTrader: (2)

Joined: Feb 2007

Posts: 1,627

Likes: 290

You ask ten people, you'll get ten different answers. I run mine .010"-.015" from bottomed out. In my findings, the engine makes more power and runs faster.