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Has anyone here reverse modified knucklehead heads from the old Panhead jug modification?
It doesn't seem like it would be that hard and I can think of a couple of different ways I might approach the problem. But rather than "re-invent the wheel" so to speak I figured someone here has done this and would be willing to pass on lessons learned.
For those who might not know what I'm talking about; back in the days before aftermarket suppliers (God bless capitalism), replacement knuck jugs were getting scarce and someone realized that the new panhead jugs would almost work. The only thing one had to do was re-locate one of the head bolts that was off by a half hole or so. They ran a bolt down, cut it flush and re-drilled a new hole in the head to match the panhead cylinder hole pattern.
So anyway I'm looking to go back to knucklehead cylinders and the fork in the road is whether to:
1) Run a bolt down, cut flush and drill and tap the original bolt hole? I can think of a couple of potential problems with this, namely unless the thread cut matches exactly, it seems like one would have a junk hole (in terms of not being able to reach torque) and I don't know if 7/16-16 helicoils exist although 7/16-20 do.
2) Easy out the original cut off bolt first and then plug the panhead hole. Then it's just a matter of cutting back the part of the plug and I'd have good threads for most of the hole to index the tap from.
I'm leaning towards #2 at this point but I thought I'd ask.
It doesn't seem like it would be that hard and I can think of a couple of different ways I might approach the problem. But rather than "re-invent the wheel" so to speak I figured someone here has done this and would be willing to pass on lessons learned.
For those who might not know what I'm talking about; back in the days before aftermarket suppliers (God bless capitalism), replacement knuck jugs were getting scarce and someone realized that the new panhead jugs would almost work. The only thing one had to do was re-locate one of the head bolts that was off by a half hole or so. They ran a bolt down, cut it flush and re-drilled a new hole in the head to match the panhead cylinder hole pattern.
So anyway I'm looking to go back to knucklehead cylinders and the fork in the road is whether to:
1) Run a bolt down, cut flush and drill and tap the original bolt hole? I can think of a couple of potential problems with this, namely unless the thread cut matches exactly, it seems like one would have a junk hole (in terms of not being able to reach torque) and I don't know if 7/16-16 helicoils exist although 7/16-20 do.
2) Easy out the original cut off bolt first and then plug the panhead hole. Then it's just a matter of cutting back the part of the plug and I'd have good threads for most of the hole to index the tap from.
I'm leaning towards #2 at this point but I thought I'd ask.
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