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Re: New crank cracked?
Posted: Thu Apr 11, 2019 9:20 am
by Dave Koehler
There ya go! How soon we forget.
Re: New crank cracked?
Posted: Thu Apr 11, 2019 10:38 am
by 1972ho
Here is a good example of a crank someone needs advice on,351 cleveland crank.
Re: New crank cracked?
Posted: Thu Apr 11, 2019 11:01 am
by Dave Koehler
welded journal. Always tough call on whether it's a real crack or a weld void / overlap.
Even a nicely welded cranks looks like doo doo under the black light.
Re: New crank cracked?
Posted: Thu Apr 11, 2019 12:51 pm
by AC sports
Here are some closer pix. Best I can do.
May actually be forging void as suggested.
Safe to run?
Re: New crank cracked?
Posted: Thu Apr 11, 2019 1:15 pm
by miniv8
I'd run that, yeah.
Looks very much like a casting/machining overlap, and its on the backside anyways.
If the ocd kicks in hard just have it ground.
Re: New crank cracked?
Posted: Thu Apr 11, 2019 4:59 pm
by GRTfast
Truckedup wrote: ↑Thu Apr 11, 2019 8:26 am
MotionMachine wrote: ↑Thu Apr 11, 2019 8:21 am
bigmike wrote: ↑Thu Apr 11, 2019 4:16 am
That is a forging void.
I tend to agree with this. Especially considering it's in line with the forging seam. When I've seen cracks like in the pic Scotty posted, they were caused from heat, just like cracks in the face of a flywheel. I've tried to grind them out but rarely do they go away with a minimal grind. Since the crank is new, it hasn't been subject to any trauma. I think it just didn't clean up completely from the rough forging when it was ground.
If so, is the crank usable for high performance ? Grind it undersize to try and clean it up?
I wouldn't use it without cleaning it up. Any surface discontinuity is a stress riser. It will probably be fine, but I tend to err on the side of caution if given the option.
Re: New crank cracked?
Posted: Fri Apr 12, 2019 11:10 pm
by MadBill
Cracks don't stop and re-start as in the first of the close up pix. I bet the crank rings vs. thuds if it's hung on a wire and tapped with a hammer.
Also, it's in a low stress region. I run it with no worries.
Re: New crank cracked?
Posted: Sun Apr 14, 2019 9:16 am
by Dan Timberlake
For OP, not RE: that nasty-*ss welded crank.
I agree the "seam" is not in the worst orientation, and assume it does truly not extend into the fillet/radius, although visual is not the best way to ascertain that.
Is this build it and forget it?
Or, is the pan going to come off several times a year for inspection, so the crack/seam could dye penetrant tested to monitor "progess?"
Re: New crank cracked?
Posted: Mon Apr 15, 2019 7:33 am
by AC sports
Ideally I don't want to touch it after building but I won't sleep easy. It does continue into the radius which is why I'm concerned. Even if it's a welding void, surely it can't be good in the radius. Barely visible there...but nonetheless.
Re: New crank cracked?
Posted: Mon Apr 15, 2019 10:00 am
by Dave Koehler
AC sports wrote: ↑Mon Apr 15, 2019 7:33 am
Ideally I don't want to touch it after building but I won't sleep easy. It does continue into the radius which is why I'm concerned. Even if it's a welding void, surely it can't be good in the radius. Barely visible there...but nonetheless.
uhhh, wait a minute. After all this you still haven't had it tested? That's on you.
Re: New crank cracked?
Posted: Mon Apr 15, 2019 12:16 pm
by AC sports
Nowhere local to test it unfortunately , hence my post asking for opinions.
Re: New crank cracked?
Posted: Mon Apr 15, 2019 10:28 pm
by Dave Koehler
OK, but you have been shown how to check it yourself via 2 or 3 methods, ranging from free to not real expensive. Become that guy.