machined rb25 crank stability...

[Chaos the Xile]

Ok, I had my crank machined due to a spun bearing on cylinder #1. After the machine work, the machinist told me I needed .25 oversized main bearings and .50 oversized rod bearings. Now I am shooting for 700+whp on my new setup, but I am scared that the crank won't be stable enough to hold the horsepower I want from the engine.

I need to know if anyone else has had this much material taken off of their crank and rran it successfully without problems. Any info on the strength of a machined s1 crank would be great too!

[Shocker]

That is what balancing your rotating assembly is for mate. Talk to your machinist to see if there is anyone local who can do it.

[Chaos the Xile]

Ok, thanks Shocker, I'll call around and see what I can find out.

[Carl H]

a machine shop that cant ballance an engine...what kind of engines do they build...briggs and stratton?

[jdmser]

I had to have one of my rod journals welded on the r33 rb26 crank I'm using in the rb24 build. While it was out a the crankshaft place my engine builder had all the mains and rods journals ground so I have to run 0.25 under size all around. As part of the package the guy doing the work also nitride hardened the crank again. Builder said the crank would work without the hardening but, wouldn't hold up to any kind of damage. It was not cheap.

[legit240sx]

do your wax messurements to the fsm specs and if they'er on then thats what you need.... i.e. why there is oversize bearings..... if your worried about the extra weight thats what balancing is fo if your worring about how far he turned it down on the crank ask the man and or any other machine shops, they would know more....