Author Topic: M47 crankshaft question (Read 3357 times)

bflan2001 · « **on:** October 07, 2011, 07:10:28 PM »

I think I finally found an M47 crankshaft that will work, but I can't find the information I need on this site or anywhere on the net. Can anyone tell me from the information below if this is the crankshaft I need?

"Hi I think the crank your after is cast 37CR only has a pulse plate at rear and is round on the nose of crank with no flats to drive oil pump if so I have got 4 of these."

DesktopDave · « **Reply #1 on:** October 07, 2011, 08:11:00 PM »

None of the M47 cranks were cast IIRC. All of them have oil pump "flats" for the oil pump drive, right?

bflan2001 · « **Reply #2 on:** October 07, 2011, 08:45:39 PM »

the 'cast 37CR' he's referring to is the casting number, similar to a part number. I believe forged parts can still have casting numbers, but maybe i'm wrong about that.

DesktopDave · « **Reply #3 on:** October 07, 2011, 09:22:09 PM »

I think you're right about the casting. There are at least three variants of that crank. I'd compare the bearing shells of each to be sure they're close. I'm thinking that if there isn't an oil drive on the nose it's not going to work...

wazzu70 · « **Reply #4 on:** October 08, 2011, 07:33:51 PM »

Yeah, its got to have the oil pump drive flats. Sorry, don't know a proper casting number.

pdxmotorhead · « **Reply #5 on:** October 08, 2011, 09:01:14 PM »

If I was thinking of a big stroker with the M47 ,,, I'd dry sump the engine.
Your already spending the big $$. A small 3 stage would be more than enough.
They can be found fairly reasonably priced at swap meets and they are fully
rebuild-able most of the time. Dry sumping can add significant HP and with a
turbo setup solves all the drain issues.

Just a thought...

Dave

bflan2001 · « **Reply #6 on:** October 09, 2011, 12:40:05 AM »

that's something i've also been looking into (assuming i can ever figure out what crankshaft i need, and then find one). not so much for the power increase but this motor is going in an E21 and the oil pan will end up sitting very, very low. it would be over 2 grand buying new parts which is why it's not on my to-do list at the moment. where are these swap meets you mentioned? i'd love to buy up some old racing parts.

pdxmotorhead · « **Reply #7 on:** October 09, 2011, 01:18:18 AM »

Look around for dirt track / circle track clubs there are swap meets all over.

The Midget race cars use smaller dry sump pumps that would rock for a M42/44.

I've seen pumps in the $250 range, youll need the pump, oil filter mount (50 bucks), dry sump pan (Can be hand built if your a fair mig welder), and use good hose (200ish), Aeroquipe, Goodrich, NOT push on or hose clamped. A used 10 to 12 quart tank is < 100 bucks if you keep on it. Pulleys are another piece, probably < 150 if you are tenaciously cheap like me. LOL

Dave

pdxmotorhead · « **Reply #8 on:** October 09, 2011, 01:32:17 AM »

Look around for dirt track / circle track clubs there are swap meets all over.

The Midget race cars use smaller dry sump pumps that would rock for a M42/44.

I've seen pumps in the $250 range, youll need the pump, oil filter mount (50 bucks), dry sump pan (Can be hand built if your a fair mig welder), and use good hose (200ish), Aeroquipe, Goodrich, NOT push on or hose clamped. A used 10 to 12 quart tank is < 100 bucks if you keep on it. Pulleys are another piece, probably < 150 if you are tenaciously cheap like me. LOL

Dave