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40-41 connies

1936 Ford flathead engine with hairline crack in block

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I recently pulled my 1936 flathead engine from my car to install new valves and found on one bank of the block two hairline cracks in the area from the valve seat to the cylinder piston hole. Has anyone had this problem with the flathead and can the cracks be repaired someway. I would like to repair the cracks before installing the new valves and lifters. Thanks for the advice, Pete

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Hi Pete, have fooled around with flathead V-8's quite a bit, and they are very similar to the V-12's used in Zephyrs, except that the cracks you describe are an expensive and some times chancy repair, a full magnaflux of the block is recommended so that no hard to find cracks are overlooked. There were 2 types of 21 stud blocks used in '36, the ones with poured babitt main bearings, are still pretty common, and would be able to be replaced easy, the poured bearings make them expensive to rebuild, the desirable and correct engine for the '36 is the LB, or insert main bearing engine, they only made the '36 type the one year, they also used them in 1937, but the waterpumps are different, more like the later '38-'48 24 stud engines, any of which will fit right into your '36. The LB's are a little rare, but are cheap and easy to rebuild, and might well be worth repairing the cracks, but have someone do it with a good reputation, and strip the engine completely, parts are often lost at the shop, good luck, Rolf

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The only accepted way of repairing these cracks is by stiching a process which involves removing the harden valve seat and drilling a series of overlapping holes, which are then filled with a tappered cast iron plug sequentially. If the crack runs down the cylindar wall it will have to be bored to accept a cast iron sleeve. This a very common problem in flat head Fords, but a much lesser extent in V12's. It is almost always caused by overheating due to lack of coolant.

These blocks were made of a cast iron alloy with a nickel and steel composition. They can only be welded with great difficulty using a special rod. The stiching method is the most successful.

Contact me if you have more questions. zephyr@shoreham.net

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