Thread: Steel crank question

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I have a 283 out of a 55 and it has a steel crank I can tell by the pinging sound. I also have a 67 327 with a small journal crank. Does anyone know if it too is a steel crank? I really dont want to break the motor down and take the crank out.

If it's the original crank, it should a a forged, small main journal unit.

Bob

the best way is to look at the crank a forged crank will have a big forging seam 3/8to1/2 and cast will be very thin the steel rings when hit at a hi pitch and will ring longer( if not all crack) then cast.this works good if you do not have the crank ID numbers at hand

What Pat said.And check me on this,but I think the forged cranks had a completely round surface where the flywheel/flexplate bolts on.Whereas the cast have a notch or two,mushroom shape if looking toward that end of the crank? Careful about going by numbers to identify whether cast or forged,they don't always tell the truth.Best way to ID is like Pat said.283 & 327 cranks came cast or forged,both cast & forged were made for each motor.

283 cranks have a round flange, 327 cranks have two notches cut out, much like a 350 crank. Check Alan Colvin's book "Chevrolet By The Numbers" for info on cranks and everything else. It's a great resource.

Bob

Bob,I have a 283 #3896944 with a crank #3876768,the crank has the small casting seam like Pat was describing and the flange is mushroom shaped,two notches.I just had it turned and the machinist said cast,and said nothing to the effect of it not being a 283 crank.Mortec lists it as a forged 283 crank but it's not forged steel. I used to have a small journal forged 327 crank and there is a big difference in the casting seam and even the color is different,the forged is lighter in color.So now I'm really confused,block,crank and heads numbers say this is a 283???

Originally Posted by shevy not heme

Bob,I have a 283 #3896944 with a crank #3876768,the crank has the small casting seam like Pat was describing and the flange is mushroom shaped,two notches.I just had it turned and the machinist said cast,and said nothing to the effect of it not being a 283 crank.Mortec lists it as a forged 283 crank but it's not forged steel. I used to have a small journal forged 327 crank and there is a big difference in the casting seam and even the color is different,the forged is lighter in color.So now I'm really confused,block,crank and heads numbers say this is a 283???

Colvin's book shows your block to be a 1967 283 block for the 195 hp version. The crank situation is confusing. In 1965, Chevrolet started using cast cranks in low horsepower versions, but according to Colvin the 3876768 crank should be a forging, not cast. It was used from 1964 through 1967. Perhaps it's not the original crank?
The blocks originally fitted with cast cranks have scallops cut out of the cylinder bottoms to clear larger counterweights than those on the forged crank. Does your block have those scalloped cut out? If so, it would have come with a cast crank as you would expect from the 195 HP 2 barrel version.

Bob

The crank out of my 283 doesn't have numbers on it.

Bob,the cylinders are the same all around the bottoms,no scallops or height difference if I understand what you mean by scallop.They extend pretty low,even on the inside,like they came down underneath the cam line farther than they have to.But the cylinders are the same height all the way around.
Isn't 67 the last year they made these motors? Maybe they just used the same mouldbox to rush out the cranks no matter the material???
HEY GERALD,SORRY FOR HI-JACKING YOUR THREAD .By the way Gerald,if that 283 of yours is a 55 yr.,I think those had the thicker cylinder castings that could be bored .125,,,,just saw a set of pistons on e-bay sell pretty cheap for those 301's.If it is the thicker casting it would be valuable to nostalgia nutts like me.

a cast crank is just that it is poured . steel starts as a hot billet block of steel then hit very hard (forging) with many tons of psi that forms the crank in a forging hammer or form and they come out looking close to it shape and some times they are twisted to form the crank . after the forging thats is why they have a big lines forging marks so wide. this is were the steel gets cut off in the forging .

>I have a 283 out of a 55 and it has a steel crank.

One thing that might oughta be noted in this thread is that if the engine's a '55, it can't be a 283. They didn't come out until '57. The only V-8 available in '55 and '56 was the 265.

Bob

OK,,,,Gerald,if it's a 57 283 it's the thick casting if it's a 265,,,ah shoot,,,,instead of punting I'll say put the crank in the 327 and buy some 302 pistons.I think I got this part right

Yeah I think it was from a 57 not a 55. I did have the numbers somewhere? I know that the block feels much heavier then a bare 350. To my knowledge it came out of a 57 Belair and was taken out to install a bigger motor. When I bought the block it had been sitting under a tree with a tarp and rope on it for around 20 years. Complete from carb to pan and I could still turn it from the flywheel. Pretty good find for $75.

Originally Posted by Gerald Streeks

I have a 283 out of a 55 and it has a steel crank I can tell by the pinging sound. I also have a 67 327 with a small journal crank. Does anyone know if it too is a steel crank? I really dont want to break the motor down and take the crank out.

ONLY WAY TO TELL,IS TO TAKE HER APART,UNLESS YOUR THE ONE OWNER,,
IF YOUR THE 1 ST OWNER YOU MIGHT BE ABLE TO RUN THE NUMBERS AND SEE..CHECK AT MORTEC.COM THATS A NICE SITE TO GET THE FULL SPECS ON MOST ENGINES

There is 1 big giveaway with the early chevy blocks, the 55 had no oil filter boss cast into the block. This was introduced in 56. The 283 was rolled out in 57.

The 2nd smaller giveaway is that all blocks from 55 to 57 had the front engine mounts only. In 58 Chevy changed the castings slightly so that the side engine mounts that we are familiar with were introduced into the design.

All 58 to 62 283's can be safely bored to 4.00 inches. I assume this is when they were relatively new. So here we are a half century on bear in mind all the corrosion and and other faults. But who knows you just might get lucky.