You could, but I would stick with stock A series mains. Otherwise, you would need to cut new notches in the block for the center tanks of the A+ bearings.

The stock A+ crank is  NOT crossdrilled, and the A+ lower main bearings have NO oil groove, therefore the rod bearings get starved of oil for 1/2 every revolution.. not good IMO.

Rod bearings (big journal) are the same for both cranks.

Looks like we replied at the same time 

Thanks, I'll go for the 6232 with the oversize thrusts.  Would I use standard A+ 1300 bearings with that?   

Cheers,

Craig

Craig, see my post above.

I know a bit about this subject, as I run a Mk1 S crank in an AA auto block. I have to grind around .015" from standard thrusts to do mine.

Yes, it is a 1275 Cooper S Block.  It sounds like this makes a difference with the thrust washers?

The 12G1505 crank is the big journal 1275 A series one.
It is interchangeable with the 1275 A+, CAM6232 one.
If you are putting it into an S block (which has a 1/32" narrower center main width) you will need to use +.030" thrusts and check the end float, surface grind their backs if needed.
If you are going to rev it, allow extra end float, .003" in the book is NOT enough, as I found out the hard way. .006" is fine.

Am I the only one reading Cooper S block? Steve (CTR)

OK 1505 is a pre A+ A crank. but what block are you dealing with? And what rods?

A and A+ cranks are interchangeable with no mucking about with thrusts or mains.  The only difference i can think of between A and A+ are the actual bearings and the retaining tangs on the block.

Thanks Kevin, I didn't think (or know) that A+ cranks fit in pre A+.

Good news!

I think if you use an A+ crank you will need to mess with the thrust washers. The AA auto cranks have small journals and I think the different thrust spacing. I recently pulled one and had it ground 10 / 10 should be a good one. I have used them in race engies but they tend to crack after a season of 8000 plus service. Steve (CTR)

Fit a 1275 A+ crank, they drop straight in.
[edit] p/no is CAM6232.

If our host doesn't have them, try Minispares or Minisport.

I'm wondering if there is an alternative to the 12G1505A crankshaft with similar specs for a non A+ Cooper S block?  

My oil pressure is OK due to very high force spring and a steel ball instead of the standard plunger, but when hot it gets down to 15psi or so, and if parked for more than about 3 weeks without starting it up, it never builds oil pressure as all the oil drains out of the pump.

When I had it out of the car last, I replaced the bearings with what was previously in it, but it already had +.040" main bearings and +.020" rod bearings.  There are no more oversized bearings than .040" so the crank is done.

I have not checked into having the journals welded and re-ground, but I assumed that would not be cost effective.

Any ideas or suggestions?

Thanks,

Craig