Internet Crankshaft ID test.

Why would someone do this to a SBC crankshaft?

It appears to be tig welded and the flywheel is NOT counterweighted.

I have asked ol skool rodders and race car guys etc, nothing.

What da hell?

If it's a 400 crank with the mains turned down for making a 383 you either need a 400 flywheel with the counter weight or a weight added such as that one but it looks to be MUCH larger than the normal weight that is sandwiched in between the flywheel and crank flange.

It looks to me like a 400 crank balanced for a manual flywheel. According to the machinist who re-balanced my flywheel for the 400PI engine I had in a GMC truck with a 4 speed, 400's never came with a manual transmission so he had to counterweight the flywheel. The crank in the picture definitely had a manual transmission behind it.
EDIT: In my opinion that crank is scrap metal... whether they run a scattershield or not.

some one to cheep to pay for some malory slugs?

Actuallly that flywheel may be balanced....notice all the partially drilled holes on the outer circumferance...someone may have removed weight from the heavy side of the flywheel??? Just a thought..
Either way, I'm with Jim on the scrap thing...

zukkev said:

Actuallly that flywheel may be balanced....notice all the partially drilled holes on the outer circumferance...someone may have removed weight from the heavy side of the flywheel??? Just a thought..
Either way, I'm with Jim on the scrap thing...

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I thought that first.

But after looking at the pattern on the back of the flywheel you can see it was mounted with the heavy side on the same side as the heavy side of the flange.

So along those lines it would actually add weight in the wrong direction to balance it.

I just dont get it.

Maybe it was still too heavy on the opposite (so to speak) side??? And they added the weight to the crank??? Or it has the wrong flywheel for the application, and they tried to make it balance??? Have you heard/felt this motor run???

zukkev said:

Maybe it was still too heavy on the opposite (so to speak) side??? And they added the weight to the crank??? Or it has the wrong flywheel for the application, and they tried to make it balance??? Have you heard/felt this motor run???

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I know, I just dont get it.

A SBC should NEVER have a counter balanced flywheel like a BBC.

That flywheel is not a counterbalanced one either, it looks like all the other stock chevy flywheels I have around here.

The only reasonable answer I have got is from a stockcar friend that said he has seen guys counterweight a crank and then counterweight a flywheel to match it, for NO GAIN in performance only to **** a claimer engine.

The guys with claimer rules will do this so when you claim their engine you dont get the matched flywheel with it. Then when they try to run the claimer engine it rattles all to hell and lets go.

Im just lost. :booo:

Who said everything needs to match your version of logical? Maybe it was an experiement.

CHOP SHOP said:

The guys with claimer rules will do this so when you claim their engine you dont get the matched flywheel with it. Then when they try to run the claimer engine it rattles all to hell and lets go.

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True or not, that's just funny!!!

Glenn said:

Who said everything needs to match your version of logical? Maybe it was an experiement.

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If it dont fit my logic, then its stupid.

Im trying to figure out if its logical or stupid.

Obvoiusly it was done for a reason and by someone who is (im assuming) familar with SBCs.

This dont fit the typical "jerry rigged" column. It had some thought put into it by somebody.

If I can figure out why, then Ill know when.

What did it come out of, maybe this will give some clues....Race car, dump truck, DD.........

the only thing I can think of is if they shaved off some weight in the inside on the crank to install larger rods or clearnced the crank instead of the block when putting the 400 crank in the 350 block.

Question? Is this a marine engine, which was modified to run in reverse direction. (Is that even possible?) (although I don't understand why welding weight on the crank would have any benefit)

It was in a street jeep. The engine is way more than the wussy jeep could handle/put to the ground.

My best guess was he was building a jeep and one his buddies had a jeep racing engine/.tranny combo that he got a deal on.

Its a SBC with a single plane intake and a scatter shield and a Muncie M21/22 tranny married to a Dana20 case with centerforce clutch too.

Im thinkin the engine was in something where it got wound tight.

im gonna go with the fact its a 400 crank...and somebody couldnt find/didnt wanna spend the money on a correct flywheel..the other thing is..you can get a weight plate for just that purpose...but it takes longer bolts..mmabye they didnt have longer bolts,wanted the jeep done and just welded it to the crank?

TreeClimber said:

Question? Is this a marine engine, which was modified to run in reverse direction. (Is that even possible?) (although I don't understand why welding weight on the crank would have any benefit)

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In the old days yes. Never seen a counter weight though on a reverse rotation sbc. In current times, they just run one transmission in reverse

skinny_pedal said:

In the old days yes. Never seen a counter weight though on a reverse rotation sbc. In current times, they just run one transmission in reverse

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Not that it matters,

But it was cool, I rolled back down a hill climb after killing my 22r and it started BACKWARDS!!!

It didnt sound good but it ran backwards till I shut it off.

Another random reverse engine fact:

Thats how newer Polaris snowmobiles have a R gear. You push in the reverse button, it shuts the motor down and starts it in R. Then when you select out of R it shuts down and starts up forward.:redneck:

boardbysled said:

Another random reverse engine fact:

Thats how newer Polaris snowmobiles have a R gear. You push in the reverse button, it shuts the motor down and starts it in R. Then when you select of of R it shuts down and starts up forward.:redneck:

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same with golf carts