What lifters to use in my application and lifter preload
09-11-2022, 05:05 PM
#1
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What lifters to use in my application and lifter preload So I'm rebuilding an LM7 out of my 2006 Silverado. Already got most of the parts like a complete gasket set, all new bearings, cam, rings, etc. This build will be a completely stock rebuild internally. I might add headers for a slight power increase but not sure yet. I only want this truck to be for hauling but I also don't want to cam it, so I don't need the most expensive lifters, just something a little better than OEM so they'll last me a good while. About a year ago, my LS3 in my 5th gen Camaro spun a rod bearing so I pulled it out and did a stock rebuild as well. Since it was my first engine rebuild, I didn't know many things. One thing that I kept coming across was setting lifter preload. I saw how some people did something like 0.50 lifter preload or 0.80 lifter preload. I didn't really know what the lifter preload procedure was so I followed a YouTube video from Coverman66 where he showed that in order to torque down the rocker arms, I just needed to tighten down the rocker arms until the pushrods were at 0 lash, spin the crank to verify that the lifter was at the base of the cam, and then just torque them down to 22ft-lb. This method worked for me but I only had the car a few days after the rebuild before I sold it. Should I follow that approach again for my LM7 or is there a different way to do it? Like I said, I'm just a bit confused when I see people talking about setting lifter preload. Any suggestions on lifters are welcome. TIA
09-11-2022, 06:29 PM
#2
TECH Senior Member
If you are rebuilding with all stock unmodified parts, a set of 7.400 pushrods and LS7 lifters (the default replacement lifter nowadays) will assemble correctly and lifter preload will determine itself.
HOWEVER, if you are milling the heads and/or block, preload and pushrod length need to be checked.
There are innumerable threads here on doing this, mostly uniform in technique.
HOWEVER, if you are milling the heads and/or block, preload and pushrod length need to be checked.
There are innumerable threads here on doing this, mostly uniform in technique.
09-12-2022, 05:08 PM
#3
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So I'm rebuilding an LM7 out of my 2006 Silverado. Already got most of the parts like a complete gasket set, all new bearings, cam, rings, etc. This build will be a completely stock rebuild internally. I might add headers for a slight power increase but not sure yet. I only want this truck to be for hauling but I also don't want to cam it, so I don't need the most expensive lifters, just something a little better than OEM so they'll last me a good while. About a year ago, my LS3 in my 5th gen Camaro spun a rod bearing so I pulled it out and did a stock rebuild as well. Since it was my first engine rebuild, I didn't know many things. One thing that I kept coming across was setting lifter preload. I saw how some people did something like 0.50 lifter preload or 0.80 lifter preload. I didn't really know what the lifter preload procedure was so I followed a YouTube video from Coverman66 where he showed that in order to torque down the rocker arms, I just needed to tighten down the rocker arms until the pushrods were at 0 lash, spin the crank to verify that the lifter was at the base of the cam, and then just torque them down to 22ft-lb. This method worked for me but I only had the car a few days after the rebuild before I sold it. Should I follow that approach again for my LM7 or is there a different way to do it? Like I said, I'm just a bit confused when I see people talking about setting lifter preload. Any suggestions on lifters are welcome. TIA
09-12-2022, 06:23 PM
#4
The higher preload say .80 is preferred. There was a time a little while ago where .50 or even .30 was preferred. I never agreed with .30 and now disapprove of .50. This has nothing to do with quieting noisy lifters. Larger preloads stiffen the valve train. The tighter the preload the more it acts like a solid. Less pump up and float. Set them tighter, but don't get ridiculous like say setting .100 preload for a .120 travel lifter.
09-12-2022, 06:27 PM
#5
TECH Senior Member
It is .050" or .080", NOT 1/2" to over 3/4"!!!!! Unless you're talking metric, which I doubt. I'm not trying to be a hard ***, but this is how people perpetuate incorrect mathematics and terminology. Like 'my new cam has almost 280° lift, and .650" duration!!' Sorry, but it drives me up the wall!!! If I wasn't a Toolmaker most of my adult life, it probably wouldn't bother me. I'm not perfect either. I still type ft/lbs, because that was how torque was referred to back in my youth, when its pretty obvious correct terminology is lb/ft. Anyway.....Best of luck to you.......
It clearly demostrates someone not knowing what they are talking about.
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