Cracked block question

Charlie M · Jul 31, 2010

I was at a local junk year last week and there was a nearly complete BN sitting there. I was thinking about it as a new project. Turns out it has a cracked block. Is there a way to tell looking at it if the block is only cracked on the outside or do I need to put some water in it and see where it runs out. I'd hate to drain the oil at the site and have to deal with the disposal afterwards. If the block is only broken to the outside I don't have a problem getting it welded. I plan to use it as a farm tractor so looks isn't important to me and taking it as is would save some money from buying another engine.

Red Dave · Jul 31, 2010

The most common place for a BN block to crack is the lower water cavity, which is behind the carburetor. There is no pressure in the cooling system, so many, many blocks have been "fixed" by merely sealing up the leak with epoxy or silicone. May not be the best fix, but it is done all the time.

Those blocks also crack the deck of the block between 1&2 cylinders and 3&4 cylinders. That is more serious and can only be discovered by taking off the head and looking at it.

Tom Fleming · Aug 1, 2010

Red Dave is correct, 9 times out of 10, when the C-113/C-123 blocks crack behind the carb, the deck also has a crack. It shold be noted, that I have seen running C-113 engines with the block repaired, and the deck cracked that did NOT have a problem in the combustion chambers. It is always a gamble, and I have seen them go both ways.

If the rest of the tractor is in decent shape, and you do your own welding, why not give it a try. Worst thing it is going to cost you is time, and the cost of a head gasket. If this is going to be a trailer queen, it might be worth the chance. If you are going to work it hard, then I personally would not chance it.

You be the judge.

as always, IMHO.

Montana Rancher · Aug 1, 2010

I bought a Super C with a cracked block and a stuck engine. I had a deal in place for a replacement engine but the deal fell through after I bought the tractor. Pulled the head and was able to free up the engine, then used JB weld to fix the crack behind the carb. 11 years later I just finished raking 80 ac. of hay with the tractor last week

APF

Cracked block question

Charlie M

Well-known Member

Red Dave

Well-known Member

Tom Fleming

Well-known Member

Montana Rancher

Member

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