forged or not?

[benflynn]

how the hell can we actually find out if a (penta)crank is forged, the ms said it was, still not convinced, maybe we should just tell them to stroke it and see what happens

[JW240]

something thats cast has a small line where the 2 halves of the mold were separated.
a forged piece has these lines too but they are much wider.

IIRC, forged sounds different from cast. Hit it with a small hammer, and see if it rings (forged) or not...

[gsellstr]

There's a thread on here about em with pic's as well.

Wow, search function is helpful!!
http://forums.turbobricks.com/showthread.php?t=32260

[benflynn]

thank you, cast crap, guess i have a 35$ penta crank for sale

[RYRY745]

your supposed to build up a stroker motor and tell us when it fails.

[BB-Q]

Has anyone got any evidence of crank failure on a redblock?

[JohnLane]

I've never seen a crank fail.
Rods? Check.
Pistons? Check.
Caused by detonation? Check.
Caused by overheating? Check.
Caused by low oil pressure? Check.
I've yet to see a broken crankshaft in a redblock.

[swedefiend]

I've yet to see a broken crankshaft in a redblock.

There are pics of them floating around.

I have seen them posted here (Infector944?)

Anyway, I think this takes serious effort and a little bad luck.

If anyone is serious about having a forged crank. There are places that will press one out for you. $1500 IIRC.

[BB-Q]

Or get a billet one from Stereophile33 in a selection of strokes for $499. It's a no-brainer, really.

[Dauntless]

Or get a billet one from Stereophile33 in a selection of strokes for $499. It's a no-brainer, really.

Whaa?? This is news to me.... B23 versions?

[BB-Q]

http://forums.turbobricks.com/showthread.php?t=75006

[Matt Dupuis]

If Infectors crank was broken, was it caused by a busted rod or something else? Still, one busted crank out of how many thousand engines have we been thru???

And AQ131s will NEVER give up a stroker crank, for future reference.

[gsellstr]

If Infectors crank was broken, was it caused by a busted rod or something else? Still, one busted crank out of how many thousand engines have we been thru???

And AQ131s will NEVER give up a stroker crank, for future reference.

Agreed!! Go for the 151 or 171 to get the 86mm crank. Of course if you find a 171 you'd best be using the head as well. :badboy:

[towerymt]

Question: were you wanting a forged crank simply to have it modified to change the stroke?

Someone has posted pics of a broken B23 crank before.

[davidmacq]

I think he was the one with the AQ131 crank. Purchased to make a stroker I guess.

[The Aspirator]

Stand the crank up, tap it with a peice of metal. The forged crank in my B23 ringed so much it started to get annoying, very high pitched. Even just wiping the dust off with a paper towel made it ring a little bit. I haven't tried this with a cast crank but I'm guessing that a metal tap would lead to a thud.

[benflynn]

found it on ebay about a year ago for 35$ shipped. i figured for that $ and it might be forged, someone told me only the 2.5l crank was forged. then greg's ms said his was forged so i just wanted to see a picture of the parting lines. i don't really care about more displacement, just figured it was stronger. I have not seen a broken crank, or a hole in a piston

[smosit]

the original motor in my '67 threw the #3 rod out the side of the block and in the process the piston shattered like glass. i put it back together with scotch tape just for fun.

[ElPiloto]

A forged crank is stronger than a cast crank. However I would choose a CAST crank for an inline 4 cylinder engine. The reason is internal dampening. 4 cylinder inline engines are difficult to balance because they generate harmonic oscillations greater in number and occurance than any other engine. Except maybe a 45 degree twin, Harley Davidson.

A cast crank dampens these harmonics while a forged crank does not.

I would choose a cast crank for any engine that will be driven on the street.