Pushrod length checking question?

[TSAEB]

jim what lifters did you use? i know you said oem and from my understanding all lifters now for lt1, ls6, etc etc or the ls7 standard lifters. Not the caddy "race version". And what size rocker stud are you using ?

sorry for all the question but im in the same boat right now. Im using a solid lifter(ls7 lifter with spacers) and adjustable pushrod with 7/16 studs and 1.6 comp nsa rockers. My engine builder told me not to use to much preload on the new ls7 lifters. so im just trying to make sure i understand all this.

another note theres alot of opinions on preload for the ls7 lifters. i see everything from .03-08 preload. I however always recommend what your builder says.

[Bowtiedad_Z28]

I used some original oem lt1 lifters out of a 30,000 mile car. I also used 7/16 studs. I took one of my old oem lifters and made it a solid to check my pushrod length with, using a adjustable pushrod. Here is what i used to figure my preload. I used the .025 for 1/2 turn preload with a 7/16 stud. You add that measurement to the pushrod length you came up with for your correct pushrod length.

[TSAEB]

gotcha. mine ended up pretty short the adjustable pushrod ended up at 6.94 (havent decided on the preload)...lol .... but i have le2 heads, and milled them again, block was decked , slightly thinner gaskets, and the ls7 lifters inside is about .05 higher or taller then the lt1 stockers.

thanks jim.

[Can't Explain]

......and the ls7 lifters inside is about .05 higher or taller then the lt1 stockers.

thanks jim.

The Ls7 lifters are not taller than the LT1 lifters. They look like they are but when measured from the push-rod cup to the bottom of the roller bearing they are the same height. Also, straight from GM services, the LS7 lifter is a direct drop in replacement for the LS1 motor with no changes necessary. GM has not changed their roller lifter sizes since 1987 with the L98 TPI, so I could install LSx style lifters in my 87 roller block if I wanted to.

Pre-load for the LS7 lifter is 0.030 to 0.080. Seems most people perfer around 0.060 - 0.080 since it seems to make them a little quiter and thats where I would recomend for the LT1 as well.

7/16" rocker studs help keep the the stud from delfecting under high RPM's and when high compression springs are used. I have had some 3/8" rocker studs crack and break from metal fatigue.

[TSAEB]

I will double check. But when I made one solid I measured the ls7 and lt1 with a caliper. Checking both diameter , height and from inside of cup to top of lifter it was indeed taller with the over all length the same . I'll check again if post pics If I see different. not saying your not right . I just want to make sure I'm not stating false facts.

And my previous 6.9xxx final measurenment was wrong... I set the solid lifter wrong...my valves markings are looking better and will need minimum 7.05-7.1 pushrods. I know that sounds really short so I will check it one more time .

[Can't Explain]

From Scoggin Dickie

The LS7 lifters are THE LS1 replacement, period. It is not an overflow of LS6 lifters that are used in a money making marketing ploy as you said, they are not any different that whatever you are calling "true LS7 lifters" because it is the exact same lifter. Please don't make public claims of such things as it is a rather slanderous accusation towards those of us who market the parts, and it is outright incorrect information. Both the LS7 and LS1 replacement lifters are the same part, and there are actually several shared replacement parts between the two, quite contrary from the "not one part" claim you make. Bearings, lifters, head bolts, freeze plugs, gaskets, sensors, etc are all the exact same parts.

http://ls1tech.com/forums/11872333-post16.html

[TSAEB]

Yes I agree with that. That it is the same lifter replacement for ls1, lt1 , ls7 etc . And can be used as a drop in.

I checked again yesterday.... I had my oem 93 lifter and new ls7 lifter ... From roller to top BOTH Measured 2.6 .... Now when I measured from top to center of inside cup.... Ls7 is indeed .05 thousands higher then the 93 lt1 original...And there's a few post on ls1tech that found the same thing.....but I am seeing now the difference is not enough to make any real change. So using it as a drop in would be fine.