Another Crank Question

[GRANDNAT87]

I have a 4.1l crank that I am putting in my turbo car and am pretty sure it is a turbo crank. I have had it turned 10/10 and you cannot see the rolled edges on the rod jurnals. You can see them on the mains and it is pretty aparent. I have read all about this on the thread pages and on turbobuick.com. I have heard that the fillets on the rods may go away and you cannot see them on some of the 4.1 cranks. I also read the casting numbers or the "n" on the cranks don't mean anything. I am going to push the car pretty hard 10.90's or so and want it to hold up.
If it is a na crank will it hold up? Some say yes and some say no.
I have already invested a lot of money having it maged, turned and balanced (rotating assy) and dont want to have any problems.
HELP!
Rick K

 

[Intercooler]

Not a turbo crank. Even at .030" you will have a fillet visible. Sorry!

 

[Jimn8or]

I was under the, apparently wrong ASSumption, that all 80-85 BOP & C 4.1's had the rolled fillets on both the mains and the rods??? Where is my goof on this theory.
TIA
Jim

 

[Nick Micale]

It is NOT your theory that goofed, the crank may have been removed from a Buick 4.1, but that does not mean it is the original crank the factory put in there. Lots of 4.1's had problems pulling those big Cads and Buicks, and lots of cranks were replaced by dealers.

My info is from a local Cad tech that worked on them when new. The GM parts division does use the SAME number for N/A cranks and turbo cranks. Also, casting number is the same.

I have been fooled just by looking at a couple used "rolled fillet" cranks that were NOT! After use, they have a dark shaded mark that appears to be a fillet depression. Always use the fingernail test before you pay money for a "rolled fillet" crank. Anyone need a nice, polished N/A crank cheap?

 

[copteaser]

What is a rolled fillets?

 

[Jimn8or]

Thanks alot, again, Nick.
Jim