I did not run the motor without the valve covers.

Oh, and I have to post negative feedback on gmpartshouse and Gene Culley. He is a sponsor of many of these forums and I had heard many great things about his service. Well, he will not take these bad lifters back. He says I have to take them to the dealer for testing and return! Yea right.... I'm going to try to dispute the charges with my cc company. Unbelievable.

 

The push rods should be purchased after the "new" lifters are in. For all we know the lifters could be giving you the wrong pre-load measurement and you could be back at square one in a few days after measuring for push rod length after the "new" lifters are in. I understand your urgency though. My fingers are crossed for luck that you are fortunate. Sounds like you've got quite an arsenal of push rods now.

Odd that an entire batch of LS7 lifters are the culprit. I'll scratch my head for awhile trying to figure that out.

 

We did not test all 16 lifters, but at least 8 are bad. No one else can think of anything else that would cause this problem. Either the LS6 springs are too strong for the LS7 lifter, or the lifters are bad.

 

The stock LS7 camshaft has .591" of lift. That kind of narrows it down I think.

 

If anyone has any other ideas, I would be glad to test them out.

I read a few similar problems on LS1Tech. I could not find one where they had 8+ bad, but there were cases of 1-2 that had the same issue as me - new LS7 lifter collapsing for no reason. I sure hope my cam is ok. Guess we better pull that to make sure.

 

Thinking out loud.

Hydraulic pressure is what keeps the lifters up, right? All these tests (where the spring opens/lifter falls) have been done with the engine off. Two thoughts came to me, but I could be completely wrong.

1. Could the oil pressure be lost somewhere when the engine is turned off, causing all the lifters to collapse?
or
2. Let's say one lifter drops. Would that cause the oil pressure to fall off, causing the others to drop? If that's the case, then it could just be one bad lifter.

 

I have no Idea... It may be 1 or 2 liters not functioning properly but unfortunitally you will have to take it all apart any way. FWIW I have always had the best luck with pumping them up first and then installing them... I did a 1952 caddilac engine and the lifters we got in the kit are Not exactally of the best quality... Any ways I decided it was best to pump them up since it wasn't going to be fired any time soon. Some of them pumped up right away while a few others I had to work at for a while... I can only imagine the problems I would of had if I had not done this.