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Model B rebuild questions

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dadsdream
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Model B rebuild questions

Post by dadsdream » Sat Oct 29, 2016 8:02 pm

I am doing a total rebuild on a 1940 Model B engine. Engine #3168. This is my first time and have several initial questions:
1. Is there an engine manual available which will include all specs?
2. Are there comparable push rod bearings that I can get as replacements?
3. Drive shaft bearings?
I don't want to pull apart until I know what I can replace.
Thank you

jim g
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Re: Model B rebuild questions

Post by jim g » Sun Oct 30, 2016 12:12 am

dadsdream wrote:I am doing a total rebuild on a 1940 Model B engine. Engine #3168. This is my first time and have several initial questions:
1. Is there an engine manual available which will include all specs?
2. Are there comparable push rod bearings that I can get as replacements?
3. Drive shaft bearings?
I don't want to pull apart until I know what I can replace.
Thank you
Most of the B engine blocks up to the late 40's are babbitt bearing blocks. Which mean bearings have to be poured and machined. There not insert bearings like engines today. Starting in the early 50's the blocks became insert bearing blocks. But depending which block you have there are 2 or 3 different styles of main bearings. The last 2 B's I rebuilt for customers we had to machine the block to accept the only style of bearings we could find for it.

You will have to pull it apart to find out what you have. Unless its been sitting somewhere for 50 plus years. You will probably have a later block. As Chris Craft in the early 50's quit suppling parts for the babbitt blocks and were selling new complete assembled blocks with insert bearings as replacements.

There is not really an engine manual for the B engine. You might be able to find the Hercules engine manual but a lot is different between it and the Chris Craft engine. The first 2 pages of the Chris Craft Model B parts book has all the spec's a machine shop needs to rebuild one.

Also do your self a favor and sleeve the cylinders when you rebuild the engine. It will save you from headaches down the road.

Pictures of the last Model B I just finished that had been rebuilt by someone else 10 years ago and was bored .030 over. It opened up a hole in the side of the cylinder wall.

This is the third or fourth one I have had to redo that wasn't sleeve when it was rebuilt.
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drrot
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Re: Model B rebuild questions

Post by drrot » Sun Oct 30, 2016 8:58 am

B engines before #26959 were originally babbit.
Jim Staib
www.finewoodboats.com


1947 Penn Yan 12' Cartopper WXH474611
1950 Chris-Craft 22' Sportsman U-22-1532
1957 Chris-Craft 26' Sea Skiff SK-26-515
1968 Century 17' Resorter FG-68-174

dadsdream
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Re: Model B rebuild questions

Post by dadsdream » Sun Oct 30, 2016 7:28 pm

Thank you for your responses. It sounds like my engine will have the babbit bearings. Hopefully they will not need to be replaced. The cylinders look good and compression was 110 and up in all 4 cylinders before I took it apart. I was only going to hone and re-ring. I guess I should sleeve and re-ring. Do you know where I can get the Chris Craft Model B parts book? A good source for selves and rings?
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jim g
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Re: Model B rebuild questions

Post by jim g » Sun Oct 30, 2016 7:44 pm

Look for a casting date on the block. It usually right above the oil pan flange.

The engine that I posted a picture of is out of a 1937. The owner swore it was the original engine. Well everything but the block was original. It had been change out with a replacement one from Chris Craft. All the bolt on parts were pre war.

Picture of what the casting date might look like.
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dadsdream
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Re: Model B rebuild questions

Post by dadsdream » Mon Oct 31, 2016 6:20 am

Hmm...the only numbers I can find stamped on the block are 27158 which is on the side behind where the generator mounts and also on the flywheel end near the head gasket. The other stamp is 407624 1XB which is located on the same side in the middle near the head gasket . (If you open the pictures they turn right side up)
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jim g
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Re: Model B rebuild questions

Post by jim g » Mon Oct 31, 2016 10:01 pm

dadsdream wrote:Hmm...the only numbers I can find stamped on the block are 27158 which is on the side behind where the generator mounts and also on the flywheel end near the head gasket. The other stamp is 407624 1XB which is located on the same side in the middle near the head gasket . (If you open the pictures they turn right side up)
Its IXB which is the Hercules model designation.

Your going to have to pull the bearing caps and see what condition and type bearings you have.

dadsdream
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Re: Model B rebuild questions

Post by dadsdream » Thu Nov 03, 2016 4:05 pm

Are there any torque specs available for the Model B? For bearings, head etc?

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drrot
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Re: Model B rebuild questions

Post by drrot » Thu Nov 03, 2016 7:02 pm

From the manual
Attachments
B torque specs.jpg
Jim Staib
www.finewoodboats.com


1947 Penn Yan 12' Cartopper WXH474611
1950 Chris-Craft 22' Sportsman U-22-1532
1957 Chris-Craft 26' Sea Skiff SK-26-515
1968 Century 17' Resorter FG-68-174

dadsdream
Posts: 22
Joined: Sat Oct 29, 2016 7:35 pm
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Re: Model B rebuild questions

Post by dadsdream » Thu Nov 03, 2016 7:17 pm

Excellent...thank you Jim!

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