I'm using 145 lb seat pressure, 420 open with the stock lifters.

If you collapse a lifter, it was worn out to begin with.

Mike

 

That's interesting. Myron Cottrell of TPIS was pretty specific about not using over 140# of seat pressure with stock roller lifters, he didn't say anything about wear. Maybe you just like living on the edge, Mike! Or maybe TPIS just plays it safe, which is probably the case.

 

Would 1.5 and 1.6 RRs have a different affect on open pressure? It would seem that 1.6 RRs would put more stress on the lifters... no?

 

You're right, the 1.6 rockers apply more more force to the lifter than 1.5 rockers with the same valvespring.

However, the better LS1 cam packages use 145 lb seat pressure and 1.7 rockers. That tells me that my 1.6 intake rockers are directionally safer than the LS1 stuff.

I had a long conversation about this subject with one of Comp Cams' area rep's (not the minimum wage guy that gives out cam recommendations over the phone), who told me about an Asphalt Track motor (700+ hp small block), which uses 220 lb seat pressure and 600+ lb open. They ran it on the Spin-Tron (spins the valvetrain to 10,000 rpm and uses a strobe to measure flex, float, etc. . .) with the solid roller. Then, they replaced the solid lifters with hydraulic rollers and everything worked fine.

Mike

 

Good input. Thanks Mike.

 

Now that's a test! Was that with their Comp R lifters or the factory replacements?

 

Stock GM lifters.

 

Cool! Thanks for the info! Definately counters what is generally tossed around for info on stock lifters.