Crack in my crankshaft

[1972ho]

I had another one my cleveland crankshafts magged and they tell me the crankshaft is cracked in these area,question is could this area be ground and magged again to see if the crack goes away are just not worth the effort.

[Monzsta]

I had another one my cleveland crankshafts magged and they tell me the crankshaft is cracked in these area,question is could this area be ground and magged again to see if the crack goes away are just not worth the effort.

No, Crack don't grind out. If you can see it at the surface it's already deep. Much farther than the .030-.060 you can get bearings for.

Find another crankshaft.

[1972ho]

Well this crankshaft you can’t see a crack it just shows up on the mag test.

[BillK]

The guy that grinds cranks for me has done that. He takes a small grinding stone on a Dremel and grinds some in the area where the crack is in the radius. Then he magnafluxes it again. If the crank is gone he will grind it. He always mags them one last time after grinding just to be sure. I have probably had him do this to five or six cranks over the years and have never had a problem.

[BCjohnny]

If it's a 4M type nodular factory crank, throw it away

Although they're getting rarer now, I can't see how it can be economically repaired so you can have faith in it and not risk other 'rare' parts, especially a serviceable block, being destroyed when it lets go

If you've the curiosity die grind it out yourself and buy a spray crack kit online before committing to anything else

[1972ho]

I know that’s what Castillo does with cracked crankshafts a friend of mine is having one done but it’s one of those Calles high dollar crankshaft he grinds it until the mag shows the crack is gone but then welds it to keep the journal the same and then grinds it but mine is a 4MA nodular crankshaft can’t be welded I’ll be glad when he back in commission.

[David Redszus]

Cracked cranks should be thrown away.

Now...what caused the crank to crack?

[1972ho]

https://youtube.com/watch?v=UYGzVzpWrw4&feature=share

[Monzsta]

https://www.coasthigh.com/ford-351-clev ... s/1638.htm

[1972ho]

The problem with all the so called cleveland crankshaft is no one sells a stock journal cleveland crankshaft they are all Chevy journals size and three are classes where you have to run stock type crankshaft if I ran a Chevy engine there are tons of new crankshaft to buy so there is no need to try and use an alternative method of repair.

[rustbucket79]

Does the sanctioning body not offer an option for the stock crankshaft? What style of racing do these engines run in?

[1972ho]

NHRA stock eliminator and no there are other crankshaft to be used there are some new 3.500 eagle and scat but those have 2.100 journals and there are no connecting rods that are 5.780 with a 2.100 journal unless someone had it custom made but it still would not be a legal set up.

[rustbucket79]

Well since those class engines are stock and cheap to build with easy to find heads, blocks, etc if it were up to me I’d be hunting down some more cherry crank cores.

If the crank is already showing signs of stress, the next step is 2 pieces. Cast iron doesn’t repair, you can bond material on to it but you’re never permanently repairing a crack in a stress member like a crankshaft, and you’re certainly not gambling the expensive components in a stocker engine on a tired crank.