What causes a lifter to rotate in its bore?
You will notice that the LS1 lifters have a bearing type ring on the top and bottom of the lifters. What generally happens is the aftermarket springs will cause a side loading effect on a somewhat aggressive cam lobe. You get the lifters to rock in the bore or a lifter bore that was slightly larger then the rest and eventually it will waller the hole out if you will and turn in the bore. When this happens the block usually can be repaired and fitted for a larger lifter like the better SBC ones. The SBC ones have a better bearing surface since most of the body takes the loads instead of just the two rings found on a stock LS1 lifter.

Google a SBC lifter and try to find a close up of it. I cant get on google for some reason right now.
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Now,this combination of heads, Comp cam, Comp OEM lifters, and lifter tray has been running fine in the same condtitions since spring 2004. So I don't understand what changed.
Also, upon disasembly of the heads, we found different size shims. This was apparently done the last time they were repaired after a blown head gasket, although I don't know if was the speed shop which handled the repair, or the shop they sent it to to fix the heads 'as best possible'. They are 918 springs, about 4 years old I believe.
If it lofted, will the new PRC Platinum springs and Cadillac lifters reduce that possibility? How else can I reduce lofting?
If it lofted, will the new PRC Platinum springs and Cadillac lifters reduce that possibility? How else can I reduce lofting?
Your other option is a rev kit, but I haven't seen very many for LS1's, so prepare to $$$ up if you choose that route.
I just spun a lifter and chewed it up with my tr224. I was running 918s for a few years as well. My guess is that I had a spring fail, and the lifter 'hopped' on the lobe... My 918s saw about 40k+ miles.
My bore isn't damaged though, so I'm just installing a set of LS7 lifters, new cam, new springs/seats/seals and calling a day. (more like 4 months...)
I found an old post which indicates 918's can't control the valvetrain above 6400:
https://ls1tech.com/forums/showpost....22&postcount=3
Can't find the link on Katech's site, but here is the text:
https://ls1tech.com/forums/showpost....59&postcount=5
The only thing I can find about a LS1 rev kit indicates to use lightweight components and the proper spring. My springs didn't break, but we didn't test the pressure. They may have been very weak.
Juissed: You were using a .650 lift cam on 918's? I thought Comp stated 918's were originally good to .625, then lowered it to .600 when their 921's came out? Or is that the new cam you're putting in? Which springs are you going with?
Last edited by JimMueller; Jun 17, 2007 at 06:33 AM.
I found an old post which indicates 918's can't control the valvetrain above 6400:
https://ls1tech.com/forums/showpost....22&postcount=3
Can't find the link on Katech's site, but here is the text:
https://ls1tech.com/forums/showpost....59&postcount=5
The only thing I can find about a LS1 rev kit indicates to use lightweight components and the proper spring. My springs didn't break, but we didn't test the pressure. They may have been very weak.
Juissed: You were using a .650 lift cam on 918's? I thought Comp stated 918's were originally good to .625, then lowered it to .600 when their 921's came out? Or is that the new cam you're putting in? Which springs are you going with?
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