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main bearing case races

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h.d.ryder

Posts: 287

Joined: Sun Nov 10, 2002 1:01 am

Location: Cranbrook B.C. Canada

Post Wed Jul 17, 2013 7:05 am

main bearing case races

I just picked up a 1939 ULH basket case . The motor has good condition matching number cases.
I will be lapping main brg. case races , To do this , do I cut out the lugs and replace the races with 40 and later races? Or, could I just set up on a mill and cut the lugs just below the race surface and then lap races? I searched the archives ,and I don`t quite understand .
Thanks in advance.
Larry
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woody

Posts: 481

Joined: Mon Apr 15, 2002 12:01 am

Location: Wa, USA

Post Wed Jul 17, 2013 10:57 am

Re: main bearing case races

If you use the 40 and later race, you can also drill the oil hole at the base of the V shape cast on the inside of the case just above the race.
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RUBONE

Posts: 380

Joined: Fri Nov 30, 2007 7:24 pm

Post Thu Jul 18, 2013 6:33 am

Re: main bearing case races

The '40 left race has provision for the crank seal as part of it. If you machine out the end to line bore the early type you lose the ability to have either a bearing retainer and seal. Don't do it that way. Just convert to the '40 style and be done with it.
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h.d.ryder

Posts: 287

Joined: Sun Nov 10, 2002 1:01 am

Location: Cranbrook B.C. Canada

Post Thu Jul 18, 2013 8:23 am

Re: main bearing case races

Thanks for the input Woody & Rubone ,I`ll have to order my 40 & later main brg. races first and then I`ll get a better understanding.
Larry
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Frankenstein

User avatar

Posts: 1541

Joined: Thu Jun 27, 2002 12:01 am

Location: Interlaken, NY USA

Post Thu Jul 18, 2013 9:18 am

Re: main bearing case races

when I put my 37 cases into service last year, I machined a plate out of aluminum to cover the end of the bearing housing, machined a recess in it to accept the aftermarket lip type oil seal, and then screwed it to the bearing housing so I had modern oil seal on the mainshaft. There's room to do this if the plate is just thick enough to house the seal.
I'm running a belt, so I like to keep oil out of the primary.
DD
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h.d.ryder

Posts: 287

Joined: Sun Nov 10, 2002 1:01 am

Location: Cranbrook B.C. Canada

Post Sat Jul 20, 2013 4:41 pm

Re: main bearing case races

That sounds like a cool fix Dr. D. ,Did you happen to take any pictures of your seal plate?
Thanks.
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don

Posts: 551

Joined: Fri Oct 01, 1999 12:01 am

Location: Spokane WA USA

Post Sun Jul 21, 2013 5:46 am

Re: main bearing case races

On the early cases 1937 1938 1939.
There is no oil screen or relief in the case to protect the scavanger pump.
(Oil fron the flywheel scraper galley)
If your cases are apart you might fit one.
don
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amklyde

Posts: 624

Joined: Fri Dec 19, 2003 1:01 am

Location: Wisconsin, USA

Post Sun Jul 21, 2013 9:11 am

Re: main bearing case races

If you just machine off the outside of the insert on the left case and do not fabricate something like our crafty friend Dick did, the hole in the later race for oil feed will be partially exposed and crankcase pressure will push oil out. The best conversion is just to bore out the end of the inserts to the race hole size.
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h.d.ryder

Posts: 287

Joined: Sun Nov 10, 2002 1:01 am

Location: Cranbrook B.C. Canada

Post Sun Jul 21, 2013 10:06 pm

Re: main bearing case races

Yes, and thanks for all the ideas and tips on things that should be done. I want to check all my options and get it right.

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