Buick Motorsport crank ???

[Louie L.]

Guys,
I have aquired a offcenter 4.1 block and 3.625 BMS crank. the crank is fully machined and ready to run ,but i have some issues with it. The crank is .010 on the mains and .020 on the rods. Will this cause a durabilty/strenght issues? If so , is there a limit on how much HP it will be safe up to?

Also could anyone take a look at the attached pic and advise what this all means.Obviously the bottom is the journal sizing, but how about the rest. Thanks

Louie

 

[EightSecV6]

The crank is pretty much used up, if it breaks, the most you can get a wide journal brg in is .020, this will not affect strength at all, we have made over 1000hp on a .020 forged crank

 

[Louie L.]

Bill,
Thanks for the reply.Is properly welding the crank and acceptable practice on these cranks? I will run it like it is, just looking at the future.

 

[EightSecV6]

As Far as I'm concerned I wouldnt use a welded crank in a weedeater but that is just my opinion!!!

 

[4CEFED6]

I am running a BMS crank.All the people I have asked say
the cranks are tuff as nails.The reason for all the billets out
there is nobody wanted to machine them cause they would
destroy grinding rocks like mad.GOOD crank 1000hp should
not be any problem.People tell me if I am wrong.I would
like info. also mine is ST/ST.

 

[lazaris]

Just some more input for you along what Bill A said, Im running my 3.625 .020 /.030 with no problems at the 10.40 level in a 3700lb car.

 

[Louie L.]

Guys,
Thats for the replies. I thought this topic was dead. The crank is currently being looked at by a big name reputable shop for final inspection before i move on. Im glad to hear that the undersize is not an issue.

Lazaris,
What undersize bearings are you using with your crank? Custom ?

 

[lazaris]

Im using the King bearings with good success.

 

[Mike Licht]

That crank came from Jomar racing here in Michigan. They are on the web they might be able to give you some history on it.
Mike

 

[yipekiya]

Someone correct me if I am wrong here but 20 on the rods is minor. Tim Cole (one of the origonal buick stage 2 motorsports engine program designer)had there cranks machined with 2.200 Rod Journals right from brand new to use BBC rods. And turning them 10-20-30 past this. Tim puts some wicked power through his engines and hundreds of passes. 2.250 less 20 thou is still more meat than Tim starts with. I would not think twice.

Regards
Rob