How do I tell if it is a cast or steel crank [Archive] - Team Camaro Tech

: How do I tell if it is a cast or steel crank


Cameron
Jul 5th, 01, 04:54 PM
How do you tell the difference between a cast and a steel crank just by looking at it? A magnet does stick to it and it pings when you strike it with a wrench. It is supposedly steel. Is there any other way to tell and am I doing it the right way?

oger
Jul 5th, 01, 05:11 PM
A cast crank will have narrow raised area in the center of each throw. On a forged crank It is much wider and and not as high.

roger69
Jul 5th, 01, 05:14 PM
yep thats all their is to it, you can also take a small wrench and tap a counter weight, if it rings like a bell its forged, if it lets out a thud its cast

Cameron
Jul 5th, 01, 05:43 PM
I went back to the storage building. I'm not sure what you mean by the narrow raised area in each throw, but if I tap a couterweight with a wrench with the crank standing on the flywheel end on a concrete floor, it rings like a bell. I also got the casting number (I think). I had a little trouble reading it. A couple of the numbers were a little hard to make out. This is what I think it is: 38515280. The first eight could also be a 9, but I don't think it is. The last two numbers "80" are what I couldn't make out real well. The last zero also looked like a "J". It is a small block 400 crank out of (I believe) a 1973 4 bolt main truck block. Thanks for the help.

fast66hb
Jul 5th, 01, 06:42 PM
you looking for the casting line. if its narrow and raised its cast, if its wide and looks like its been ground its forged, or send it to me and i'll tell you if its cast or forged http://www.camaros.net/forum/wink.gif

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fast66hb
Jul 5th, 01, 06:59 PM
i ran the casting #'s and the closest thing i could find was 3951529 as being a cast crank from a 400 small block. try www.mortec.com (http://www.mortec.com) for casting #'s

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camaroman7d
Jul 5th, 01, 07:29 PM
If it is a Chevy 400 crank, I am almost positive Chevy did not make a forged crank for the 400's (I am not 100% sure, but for some reason that is stuck in my head).

Royce

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70 Camaro 383ci
69 Camaro 385ci
91 Camaro RS V8 (305 TBI)
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HwyStarJoe
Jul 6th, 01, 03:44 AM
Cameron,

Like Fast66hb said, the only crank I could find that was even close to that casting number was a 3951529. That number is for a 1970-72 400ci engine. But we seem to have one less digit than you posted. I looked at PartsScavengers.com. I didn't know GM made a forged crank for 400's either.
Good luck man....

roger69
Jul 6th, 01, 04:22 AM
If its out of a factory 400 sbc
its cast

Cameron
Jul 6th, 01, 05:22 AM
It may not be the factory crank. I was told it was steel. I was also told that the block had never been bored. When I checked it, it was .030" over. I am for sure on the number of digits, the last two humbers are obviously digits, it is just very difficult to make out what the numbers are. I am going back to the storage building tonight to look at the casting marks. If I can borrow a digital camera off of my neighbor, I may post some pics so you guys can get a better look.

Cameron
Jul 6th, 01, 04:33 PM
I just looked at the crank and it has the narrow casting marks that were previously mentioned. I guess this means that it is a cast crank. Thanks for the help.