My question is mow many rpm is too many RPM on a stock bottom end? I am running a 6.0l out of a 2001 2500hd. has a pretty aggressive camshaft, hardened push rods, matched springs and roller rockers. It is in a 2001 2500 hd pulling truck with a slipper clutch and an nv4500. I took the 4l80e out and put the standard in because I was not achieving enough rpm to get into the power. I run between 6500 and 7000 rpm and lost 3 rod bearings. Cam bushings are fine, main bearing are ok, started to show some wear due to no oil pressure. I have also talked to two guys running stock bottom end stuff that cant spin over that rpm range either or they ruin the rod bearings. Just looking for some input......

Thanks Brian

 

I would say 6500 or so.

 

That's where we are all at. The other two guys running this stuff are around the same rpm with them both running turbo set ups in drag applications. I was just trying to see where everyone else was running.

 

what oil you running?

 

What clearances are you running? I suspect you need more rod bearing clearance and rod side-clearance to flow more oil past the bearings. Something in the .0025" range. Also, the stock rods have like .010-.015" side clearance, which doesn't let a lot of oil by. The oil cools the bearings as well as provides lube. Also, you need at least 10 PSI per 1K RPM (65-70 PSI) of oil pressure at those RPMs without sucking the pan dry.

 

I revved my L33 to 6800 and my LQ4 is at 6800 aswell.
sees it very very frequently

 

I am running 10w-30 royal purple


The crank end paly was set at .008".
I just got off the phone with my engine guy, It was caused by not enough oil supply. We are looking into a bigger pan and external oil pump to supply more volume and pressure.