I have a original head gasketed lt1 with a cam (.547/.544 220/230 112ls). I put in ls7 lifters. I primed the oil pump to get oil in the lifters. I heard ls7 lifters were taller at the plunger then the original lt1 lifters. They were visually. So I checked what length push rod I needed using the Comp Cam push rod length checker 7702-1. I triple checked my measurements. Tried them on three valves. Two on one head one on the other head. I used the sharpie method on the valve tip and the wear pattern on the valve is centered using 7.05 length push rods on all the valves. Normally people use 7.15 inch push rods with ls7 lifters. My question is does a 7.05 inch push rods seem like an odd size to be using with a relatively stock setup?

Thx
Derek

 

Did you disassemble the lifter and turn it into a solid lifter? Or did you use a checking spring?

Unfortunately you can't use a normal HR lifter and your normal valve springs because the lifter plunger will compress when you rotate the engine to check for length. Definitely disassemble one of the lifters and make it solid to ensure you have the correct length.

7.05" does seem a bit short; is there anything that would lead you to believe the heads/deck have been milled at all, or were thinner head gaskets ever installed?

 

Thanks Joe! I knew something was wrong when then the rocker stud nut was loose after 5 five cranks. I should have mentioned that.

I did not convert the lifter to be solid for the test.

I bought the car in 99. I really doubt anyone removed the heads since I see not a mark on the head bolts

I could not find a write up on converting a HL to a solid lifter for this test. Is it self explanatory when I take one apart. First time taking one apart.

 

It's pretty simple. Remove the spring clip holding the plunger in, then carefully remove the guts. The largest piece (the plunger) will come out entirely. Replace it with something to take its place. I used a small stainless rod cut to length. It will take some trial and error assembling and reassembling with the new piece to get it to the proper length so it doesn't compress.

Good luck.

 

I converted a LS7 lifter to solid for some tests and I got 7.00 this time. I used a 1/4 turn preload. Should I not use any preload on the solid lifter?

I measured the checking tool as well.

I see some light wear marks on a few valve tips that indicates that even with the original lifters that the pushrods were maybe .1 too tall.