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Old 04-07-2017, 08:56 AM   #20
J and M Machine
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Join Date: Oct 2010
Location: 40 Mt.Vickery Rd. Southborough,MA 508-460-0733
Posts: 369
Default Re: Flywheel housing question

Quote:
Originally Posted by marc silva View Post
I have often thought about why does the flywheel housing crack. After removing my engine and transmission to install a new engine I noticed my flywheel housing was almost cracked in half at the starter. Then it hit me. How can the engine be bolted solid at the rear, and granted it is in rubber but in my opinion it is basically a solid mount compared to springs in the front. I know the frame flexes but think about it. The motor hangs off the rear mounts causing some stress on the flywheel housing as the front bounces on the springs. Am I incorrect in my thoughts?
Yes: Part of it is the way the engine is hung along with the wishbone pushing against the flywheel housing. Everytime you hit a pothole it causes pressure on the wishbone thereby putting pressure on other parts.
Since the flywheel housing is secured to block with only four bolts naturally all stress will occur where it is at edge of block. We have successfully repaired these using our metal stitching/crack repair methods.

I wouldn't advise anyone to weld them as the weld can't flex like the parent metal can. The weld just makes it crack more.


I have enclosed pictures of typical cracks we see on regular basis with flywheel housings.

The late 1931 flywheel housing has extra reinforcing ribs and an internal band to add strength to a flimsy area. Even still with this added support they still crack.
http://www.jandm-machine.com/metalStitching.html
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