Hi guys, been a long time....... think I spun a bearing on my vortec build. I over revved it on full pulls w/tach hitting up to 7,300-7,500 several times. I assume that's too much for stock internals , anybody know the general rpm limit with 2 bolt mains and cast crank?. Just trying to decide how to upgrade. Anybody know if stock 4 bolt main vortec with steel crank exists in junkyards or would it be only aftermarket options?
Thanks in advance. Sorry if dumb question.

 

Actually BOTH exist but the steel crank is hard to find and nobody can gurantee this day and age the engine has not been swapped in a junkyard vehicle. I would keep it under 6,500.

 

I thought that all the 2500 series had 4 bolt mains and the typical cranks. The first four bolt main I had was out of a 2500 van. If you found an old police vehicle I've read that they were 4 bolt mains with a forged crank. David Vizard has published lots of tests with stock equipment that shows it can sustain a few high rpm or high power runs but in the end it goes. I'd also keep it under 6500 and refrain from lots of high rpm exercises with a 2 bolt block. I'd imagine bearing clearances will become very critical if you go this route.

 

 

My 1-piece rear main steel crank came out of a 305 marine Vortec. I used it in my last build and it did not take alot of effort for the machine shop to balance it to aftermarket 6" rods and aftermarket forged flat top pistons. I had the flexplate and balancer balanced to it as well. I have the fuel kill set to 6,500 rpm and the WOT upshifts at 6,200. My 4-bolt block was a GM Goodwrench Vortec 350 for an 8,800+ GVW Truck or Van that had ~80K miles on it but had a rod bearing eat itself from lack of oil pressure at higher RPMs. It is still stock bore. The machine shop honed it. From what I remember stock bore is 4.005 and it is at 4.008.

 

Well I feel a little dumb but great news.............

Originally on last drive I was doing a WOT from dead stop and O2 sensor blew out of header ( only about 1/2 a turn in there with boogered up threads). I limped it home sounding terrible. Fixed o2 and threads, let down jack, slipped a little as it went down hard and didn't think too much about it. Fired it up and immediately had loud knock in rhythm with a rod. thought it was toast after I felt bottom of oil pan and felt vibration.
Well you probably know where this is going..... got to thinking and looked at really good today.... the jack slipped off crossmember, hit center link and smashed into very front of oil pan. JUST A DENTED OIL PAN!
So now I just have to search oil pan removal and see if I can change out without pulling motor.

I'm going to get parts ordered and get her fixed. Much better than a shortblock build!

Thanks for responses guys, still very good info learned.

And good to hear from you Brian! You're creation is still alive and well! ( Lots of others helped with great info on here but you by far the most)

 

 

oil pan changed! Gonna finish it up tomorrow but may run to town open headers to see if I get pulled over first!

 

I spun a 2 bolt main (1997 block) to 6,300 RPM for years. I even whacked that motor with a 100 shot often.

 

The PM rods used in the later SBC were stronger than the old Pink rods

 

I bet you had some serious valve float too, just assuming stock valve springs were in place.. OUCH!!!!!

 

 

My mistake I missed that 😯