Does anyone know if aluminum Canadian flathead ford heads (un-milled heads) (un-milled block) if a 1/2 reach spark plug will work? (One of my NGK B6L pulled 3 threads out and is almost stripped at 7/16.... I would rather not insert these beautimus polished heads.... any thoughts? This f'ing plug stripped on a cold/anti-seized head....age I guess.
A M/C shop owner told me years ago that he preferred Champions over NGK's because they had rolled threads as opposed to cut threads. He had less problems with stripped threads by using them in aluminum heads.
I would be concerned about more damage occurring with what you propose than biting the bullet and inserting steel helicoils to retrieve the heads. You won't see them once installed.
I tried NGK's in some Canadian heads and the valves bopped the electrodes closed. They were supposed to be the same length as the H10's. Went back to Champion H10's and no problems since. I use a LOT of that antiseize stick stuff made for sparkplugs every time I have a plug out. Sounds like you need a plug that will reach all the way down to hold your remaining good threads, but not so far down that your electrodes get clobbered. You may need to pull the head to find the best plug for your engine.
On the stripped hole...see if it will hold with plug installed by Champion's instructions: Hand tight, turn X amount (cannot remember that...have to go home and find the book!) with wrench. If you can achieve that, you can presume you have proper gasket crush and can run. I would order a set of helicoils now! I think the turn amount is fractional, like 1/2...
Thanks Guys, Machine shop is going to timesert both heads. Expensive, but with my luck once one strips, the rest start to follow. Bruce, I am going to try and find some NOS H10's
These came on the motor when I got it, however they look to be NOS, with very few miles. 52lomofo... Here is some of Bruce's wisdom from another thread on these heads "There are a LOT of Canadian aluminum 24 stud heads and variants, but the only USA ones that I can think of would likely have had the A designation... 81A aluminum ones, very uncommon. These were used on some production vehicles, but not many, and I think most were done in by corrosion. These would of course be 24 stud center outlet. Look along the top edge near manifold--many prewar heads have numbers up there. I've got CC specs and such on these at home. 81A heads indicate '38 intro and were used 1938-42 with lots of minor variations, but I believe the aluminum ones were only used early in this run. __________________ Bruce"
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