Board index Flathead Power-Technical Questions, Answers, and Suggestions Knuckles Knuck head altered for pan cylinders....

Knuck head altered for pan cylinders....

Moderators: Curt!, Pa

Post Wed Jun 18, 2008 1:22 pm

Posts: 15
Location: SFV, California
The previous owner of my '47 did the alteration on the heads to use Panhead cylinders, which included moving one bolt hole. That's fine, but, in the process, altered the thread pattern by inserting helicoils after slightly enlarging the existing bolt holes. This was done so Panhead head bolts could be used . What would the fix be? And would it change the proper torque specs for the head bolts once done? Thanks, Bones

Posts: 1604
it rather sounds to me, as though the 'fix' is to leave it that way. Pan cylinders on a knuckle is a well-known modification for improved reliability, after all.

Quite how you would reduce the bolt size, which is what you appear to be asking, I couldn't say, unless by welding the hole and re-drilling, which sounds like a lot of work for no real useful end.
Shoot, a man could have a good weekend in Dallas with all that stuff...

Posts: 150
Location: Carver, MN

I agree, if the threads are good now, best to leave them. If the helicoils were properly installed they will take as much or more torque than stock. 65 Ft Lbs should not be a problem, but remember I said "if the helicoils were properly installed." You might be safer down around 55.

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