Crankshaft Identification

[iloveredmeat]

Peter,
In my experience, casting numbers don’t always correlate to catalog part numbers.

Thanks Geoff, that's good to know. I bought this on the word of the seller and some cruddy photos.

And then when I got it and couldn't align the part numbers, I was really worried I'd just blown a chunk of money on some other model crankshaft.

Thanks to all for helping to confirm. Phew.

Peter

[Daryl Smith]

If it otherwise looks like a roadster crank a U20 differs by:
1) longer 'nose'
2) 12 bolts for the flywheel
3) 8 counterweights (R16 and H20 only have 4)

[iloveredmeat]

If it otherwise looks like a roadster crank a U20 differs by:
1) longer 'nose'
2) 12 bolts for the flywheel
3) 8 counterweights (R16 and H20 only have 4)

Thanks Daryl.

I've wondered the difference of the H20, so I just looked at photos of H20 cranks, and the counterweight thing is interesting.

Really relieved that I didn't make a mistake buying this sight unseen.

Thanks again,
Peter

[Curtis]

Well that always remains to be seen until the machine shop gets it. I've not had a bad roadster crank yet and the U20 is way overbuilt so that's a good thing.

[iloveredmeat]

Well that always remains to be seen until the machine shop gets it. I've not had a bad roadster crank yet and the U20 is way overbuilt so that's a good thing.

Yes, Curtis, absolutely true... to clarify, I'm just glad I didn't do an obviously dumb move by buying a "U20 crank" that isn't actually a U20 crank.

So, I guess I'm halfway to confirming a non-mistake.

Now about the assessment. I wasn't told WHY it was taken out in the first place, though the seller said it is has never been turned but she thinks it should be turned. And my understanding is that turning one is not necessarily a huge problem, and sometimes is needed... as with my stroker, they did a custom grind on a U20 crank and the fact that it had already been turned .010 was a non-issue.

And I suppose a machine shop will test whatever else needs to be tested.

Fingers still crossed.

[spyder]

I was just told again that it came from a 1969 Datsun Roadster 2000. I've asked for any history if possible.

I'm just really surprised that the part number doesn't give a simple, clear, and definitive answer.

Yes. 5 main. If it is an inch longer than a 1600 and heavier it's probably a 2000. 2000 will have two key way slots on it.

Thanks Curtis, it is exactly one inch longer than my 1600 crank, and weighs 47 lbs... but I don't know what my 1600 crank weighs, and I'm 531 miles away from both... so don't know if that's heavy or not... I'm relying on friends and pics

I'll have my brother check for the key slots, and to send more detailed photos.

Looks a lot like a U20 crank.

Thanks Dave. Your opinion is as strong as it gets, so I'm very hopeful.

Are there any photos I can post that would confirm without question?

I'm looking to trade or sell this, so I want and need to represent as accurately, fairly, and honestly as I possibly can.

Thanks everyone, I really do appreciate it.
Peter

[spyder]

I was just told again that it came from a 1969 Datsun Roadster 2000. I've asked for any history if possible.

I'm just really surprised that the part number doesn't give a simple, clear, and definitive answer.

Yes. 5 main. If it is an inch longer than a 1600 and heavier it's probably a 2000. 2000 will have two key way slots on it.

Thanks Curtis, it is exactly one inch longer than my 1600 crank, and weighs 47 lbs... but I don't know what my 1600 crank weighs, and I'm 531 miles away from both... so don't know if that's heavy or not... I'm relying on friends and pics

I'll have my brother check for the key slots, and to send more detailed photos.

Looks a lot like a U20 crank.

Thanks Dave. Your opinion is as strong as it gets, so I'm very hopeful.

Are there any photos I can post that would confirm without question?

I'm looking to trade or sell this, so I want and need to represent as accurately, fairly, and honestly as I possibly can.

Thanks everyone, I really do appreciate it.
Peter

A U20 weight.

[iloveredmeat]

A U20 weight.

Boom.

Thanks Spyder.

Within margin of error in my opinion.

Now to a machinist to measure and check condition.

Fingers still crossed.
PM

[Daryl Smith]

Irrelephant

[iloveredmeat]

Good news!

This U20 crankshaft I took a gamble on looks to be a good one.

I just heard from Mother's Machine Shop and they said:
"This crank is still standard and in good shape, might just need a polish. Rods – 2.0455-2.0461
Mains – 2.478-2.4785"

Phew!