flywheel bolts

[larry harding]

i am patching up an engine i bought a while back to run until i can do a complete rebuild on another engine. i did new rings and gaskets and hand lapped the valves. putting things back together i found i have one stripped bolt hole in the crankshaft. replacing the crank is something i don't want to do right now. i am considering either tap out to 1/2 20 and drill the flywheel to match, or helicoil the threads back to 7/16 20. has anybody tried either of these repairs or can make suggestions?

[RawhideKid]

Larry, I would say that since the flywheel is part of the balancing of the engine, the helicoil would upset that balancing a little less than drilling out to ½-20, after all, the reinserting of the coil would be like the weight of the original threads.

IF you decide to drill and tap to ½-20, I would also do the same to the hole opposite the new hole to try to keep the balance equal.

One thing you also need to remember, IF you do go out to the ½-20 you will HAVE to cut the head of that bolt off by almost half to insure that the clutch plate doesn't rub on it. All 4 of those bolts are special with the shorter head to insure that clearance.

[Big hammer]

Helicoil the crank flange, easy fix !

[hardtimes]

Originally Posted by larry harding

i am patching up an engine i bought a while back to run until i can do a complete rebuild on another engine. i did new rings and gaskets and hand lapped the valves. putting things back together i found i have one stripped bolt hole in the crankshaft. replacing the crank is something i don't want to do right now. i am considering either tap out to 1/2 20 and drill the flywheel to match, or helicoil the threads back to 7/16 20. has anybody tried either of these repairs or can make suggestions?

Hey Larry,
If you have the crank out of the engine already, you can have extra flywheel to crank bolt holes machined in. Both flywheel/crank obviously must be drilled. 6 and up to 8 such holes can be made. So, without unbalancing things, use the stripped oot bolt hole (and one across from it)as crank dowel hole and use 4 or 6 others as bolt holes.

BTW, if your engine is stock, 4 holes are fine as Ford intended. Less drilling needed. I'd also take this opportunity to have 65 lb stock flywheel cut down in weight... Then crank and flywheel can be rebalanced as a unit.

[Tom Wesenberg]

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Originally Posted by Big hammer

Helicoil the crank flange, easy fix !

X2

No use messing up more parts