[Tom Endy]

Many flywheel housings are found cracked at the two lowest mounting bolts. My theory for the cause of the cracks is people jacking the front of the motor up to remove the timing cover to change the timing gear. If the housing is bolted tight to solid rear motor mounts something has to give.

I would not worry so much about the cracks, what is important is that the housing is not twisted out of shape. When putting an engine together it is prudent to check the run out of the upper 180 degrees of the housing with a dial indicator. According to Ford it should be within .006.

When making this check I make a .015 thick paper gasket to be installed in concert with the two horse shoe shaped .010 metal shims that install behind the ears at the top of the housing where the throttle linkage installs. The paper will crush down to be somewhere close to .010. Most gaskets supplied by suppliers is not thick enough. I have a pair of shortened mounting bolts to use at the ears so that all six bolts can be torqued down evenly before the dial indication measurement is made.

I have put a number of engines together with cracks at the two lower mounting holes and they worked fine as long as I was able to dial in the top 180 degrees of the housing. The bottom 180 degrees of the housing is not a concern as it is very flexible and is pulled into alignment when the bell housing is bolted up.

If there is concern about the two cracks at the lower mounting bolts drill a small hole in each at the end of the crack to keep it from lengthening.

I have never been able to tell anything about tapping them with a hammer and listening to the sound. They all sound the same to me.

Tom Endy