Cadillac lifter pre-load
06-06-2008, 01:29 PM
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Cadillac lifter pre-load Just a F.Y.I for anyone, like me, that has been wondering what to set the pre-load to on the Cadillac lifters. I tried calling SD parts and asking them what the pre-load was and they couldn't tell me. I searched on the internet, found nothing. So I found the answer myself. I mounted my magnetic base dial indicator and put it on the oil hole in the rocker arm and began to slowly back off of the bolt that holds the rocker down, watching the dial. When loosening the nut, I saw a sweep of .180 from bottomed out lifter to fully extended lifter. I confirmed that reading by repeating the procedure, only tightening the nut this time. Again, .180. I had heard that .060 was the norm for LS1 lifters, however I also heard on hydrp lifters to set preload in the middle, which in this case would be .090. I am currently using a pushrod that gives .060 preload with no issues, sewing machine noise is very faint. Hope this info helps out.
06-06-2008, 01:50 PM
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They are junk and rob power, I went from .060 preload to .110 and picked up 20rwhp everywhere and herd .160 is the way to go. I'm goin back to Comp R's you guys can keep these things.
06-06-2008, 08:45 PM
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Not trying to question here but have you actually tested them against the comp lifters or are you just speculating. I am curious because I just installed a set of caddy racing lifters and am wondering if there is a better option?
06-06-2008, 10:46 PM
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In my opinion, you can't argue with race proven reliability, i.e. LeMans 24hrs and still holding together. The GM engineers have to know the LS motors better than anyone, hell they designed them. I have found in experience that GM performance parts work better than most, but not all, aftermarket parts. I wasn't trying to start a pissing match, just wanted to pass on some info for the wondering.
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06-06-2008, 10:51 PM
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personal feelings aside, I find it pretty awsome that .050 preload made that much difference. I may look into doing the same thing. It's worth a try.Even in an argument someone can learn new things.
06-07-2008, 07:20 AM
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I am in the same boat. My heads are off and I am contemplating preload figures for my Caddy's as well. There are failuers for just about every type and make of a part out there. I am sure tons of guys run Comp's with zero issues hell they lasted over 5 years in my setup that has a pretty aggressive camshaft. You read and try new stuff out if something fails just like ONEBADWS6 is doing. Nothing wrong with that. There was a guy who posted a pretty bad Caddy lifter failure(s) a while back.
06-07-2008, 08:53 AM
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I ran Comp R's for 2 years shifting at 7500 with no issues and made great power. When I switched to the Caddy's I couldn't figure out where all my power went untill I preloaded the crap out of them.
06-07-2008, 09:34 AM
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First setting geometry is the ticket then setting preload. That is also relative to cam lobe used and oil pressure/weight.
Sooo as everything modded there is no rule of thumb and experience, trial and data collecting is the ticket to go.
Also, I've yet to see any part not fail yet. If you race and you're no braking anything, well, you are just not racing hard enough
Sooo as everything modded there is no rule of thumb and experience, trial and data collecting is the ticket to go.
Also, I've yet to see any part not fail yet. If you race and you're no braking anything, well, you are just not racing hard enough
06-07-2008, 09:46 AM
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Trying to figure out the physics behind why more preload (lets say going from 60 to 110 thous.) would net more power in any lifter. Noise is one thing this is another anybody care to shoot an idea out there? Would'nt there just be less oil in the lifter cavity?
06-07-2008, 05:21 PM
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So much for 22ft lbs. of torque applied the rocker bolts. Thanks to this thread, i'm going correctly check the preload on my lifters this time. The valvetrain is somewhat loud, but I could use that 20 extra hp!
