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Phil Wimbish

Engine block issues

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Hello, 

   I found out Friday, after speaking with my machinist, that my block has some cylinders with thin walls. I do not know how many but definitely several. This is a block from 42-46 with the larger bore. He is reluctant to sleeve this engine at this stage of the game, perhaps because he knows I have another engine which is probably a '38. I do not know the condition of that block yet.  

   I hate to just trash this block, I was wondering if I have any options so I can use this block. I am not opposed to having a large bore engine.The block was sonic tested and he says we are not far from going into the water jacket in some spots. It has already been bored .020 over previously. 

   I would appreciate any other opinions.

Thanks for listening!

Phil W

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Listen to his advice. His reluctance is probably due to the expense of sleeving 12 cylinders.  You don't want to spend thousands to rebuild an engine, put it in the car and have it fail a short time later, usually just after the warranty.

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This post begs the question which I have never seen answered.  What Is the maximum diameter one can take these 12 cylinders out.  0.020", 0.030", 0.040"?  You see oversize pistons, rings, etc. often on eBay.  I know my engine is tired but have never opened it up to see what I have.  Be nice to know where I stand with this engine when the time comes.  Thanks.

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A few years back I re-bored a '42 block to accept 3-1/16" Ford racing pistons. We determined that the cylinder wall thickness came to an average of 1/4". Everything seems Ok and no "leakage of any kind hasn't occurred. Head gaskets coverage is right on the cylinder edge so that is a concern so you may have to be careful when selecting gaskets. Cylinder blocks  are probably different from '42 and '46. My '42 block has no casting numbers or letters on it. I have head that the first 1800 cars produce in 1945 (dubbed 1946 models) had casting problems so they returned to the 292 cubic inch design with other improvements for the later model '46 to '48 cars. Evident the problem with the early '46  was with the cylinder walls. Some(most?) engines couldn't be re-bored. I think it would be wise to check the date of the block you have.

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Thanks for that information.  My car is a '38 with aluminum heads and the three stud intake.  I have read that when these engines had problems back in the day, they just switched blocks.  Therefor no numbers on the block to tie it to the car.  Where do you fine the "date of the block"

Sorry to hijack this thread.

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I have collected a lot of information on engine identification from George Tricket and others over the years. Too much to post. Email me at dapring42@gmail.com.

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On September 21, 2016 at 3:00 PM, Beltfed said:

Thanks for that information.  My car is a '38 with aluminum heads and the three stud intake.  I have read that when these engines had problems back in the day, they just switched blocks.  Therefor no numbers on the block to tie it to the car.  Where do you fine the "date of the block"

Sorry to hijack this thread.

There are no dates or numbers that will specify the year. You just have to look at the characteristics of the block . The later blocks 42 & up, will have a large hump along the side of the block along the oil pan rail to accommodate the large core plug.The center one will be larger than the ones on the end.    On the earlier blocks all three of those humps are the same size.  The bore sizes changed also.  Early blocks  36-39 were 2 3/4 " .In 40-41 it went to 2 7/8.  In 42 & very early 46 blocks were 2 13/16 .  Then back to 2 7/8 until the end of production in 48. 

Edited by Ken/Alabama (see edit history)

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FWIW when I had my 47 engine rebuilt, we discovered that the back 2 cylinders on each side had been sleeved sometime in the past. The others had been bored .030 over. We ended up going to .040 over & have had no related problems.

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I would get a different block or confirm his flathead experience, have him show you the issue. Engines are getting pricy, but still plentiful--lots of rodders ......I have a 2 7/8 block with

small dimples. I looked at my parts list and had rings .060 over..

There is a good article in this Ocee Rich book, written by Buzz DeClerc or such, that discusses this topic--even if you've solved you issue, still a fun read may still be in print.. 

$_57.JPG

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