With all of the discussion about the poor quality of after market parts, I
was wondering if anyone had experience with using an anti-friction coating to
build up the piston skirts in their Healeys.
I worked a few years for a company making aftermarket high-performance
V-twin motorcycle engines. Before I left, they started using a moly-coated
piston
(Mahle was the manufacturer) installed with half of the side clearance of
the traditional non-coated piston. This coated piston proved almost
indestructible.
We Dino tested these pistons beyond abuse, by firing a cold engine up and
going to dull throttle for ten minutes at a time over and over again letting
the engine cool to under 45 degrees F between pulls. A non coated piston
would
not pass this test more than one or two pulls. After failing to seize the
engine with the coated pistons, we then ran full throttle for 8 hours with no
reduction compression or horsepower. Finally, because we now had to see what
it would take to destroy this piston, we shut the cooling fans off and
continued to run the test motor at full throttle until the aluminum heads
turned
blue and smoke was pouring out of the crankcase vent like a coal fired
locomotive charging up a hill. Upon dismantling the engine, we found that the
oil
had turned to a tar like substance, the heads were annealed from the high heat
but the pistons were in pristine condition, with no damage whatsoever. By
comparison, a non coated piston wouldn't even last 10 minutes before seizing
in
the cylinder with the fans turned off.
In their magazine ad, Swaintech _http://swaintech.com/_
(http://swaintech.com/) claims that they can apply a coating up to .004"
thick to build up
pistons on vintage cars.
One could bore out cylinders to say, .008"over and use this coating on their
old pistons with +.0010" rings sized to fit. Could this be a better
alternative to buying aftermarket pistons for our "normal" street use
vehicles???
Anyone have direct experience using this approach on their Healey or other
vintage vehicle? Swaintech's advertized normal coating thickness is .0007"
which is similar to the coating thickness used on the "new" motor cycle
pistons
that I have some experience with. Would this heavier coating thickness used
to build up a piston possibly deteriorate faster than the normal thinner
coating?
As a side note, they also offer coatings for heads and valves and manifolds
promoting better cooling.
Let the discussion begin.
Gary Bouffard
60 BN7 (still in pieces)
**************Feeling the pinch at the grocery store? Make meals for Under
$10. (http://food.aol.com/frugal-feasts?ncid=emlcntusfood00000002)
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