In a message dated 01/20/2001 12:38:24 PM Pacific Standard Time,
bellytk@nh.ultranet.com writes:
<<
Guess my only suggestion would be ensure the coefficient of expansion is
correct for the service on any filler. I'll relate a sad story. Fellow
here in New Hampshire wanted to build a huge flathead. He bought an
expensive 4 1/2" stroker, bored the motor to 3 1/2" using wet sleeves.
Bought Ross pistons and Kong heads. Decided he would dry block the motor.
Did his own research (bad mistake) and ended up with a aluminum Devcon
product. I was there the Wed night at New England Dragway to do the push
truck bit when he fired the rail up and tried to make a pass. As he
proceeded down the track the car went slower and slower. A post-mortem
showed the filler had expanded too much, squeezing the cylinder walls
causing the pistons to melt at the ring grooves. Took about 30 seconds to
ruin a lot of expensive equipment. He has sold the crank, rods, heads, cam
which were okay to a fellow out on Cape Cod. He will try for a slightly
smaller engine, less bore I believe and also put it in a front engine
dragster. Be interesting to see it run.
regards, John (NH) where we are expecting more snow
>>
John,
I tried filling a couple of Flathead blocks with a
bedding-compound epoxy product and ended up ruining them. The epoxy-type
products seem to do OK in the modern OHV blocks, probably because the cooling
capacity of the blocks are less than the Flatty. The water capacity of the
Flatty and the resulting higher amouint of epoxy needed apparently made the
filler mass unstable, even after curing thoroughly. We found that the filler
changed shape every time the engine was warmed up and raced, ruining the
leakdown when the cylinder walls moved.
I even tried boring it round again and trying a different set of pistons
with the same result.
The Flatty dragster guys seem to like filling their blocks with aluminum
or cement. With the aluminum they can thread the head studs down into the
filler to stabilize them better and stand higher head torque figures.
At the Salt, McCain & Houtz have run filled blocks for years, pushing the
race car to the mile marker and making a Banzai run through the first or
second timed mile. They ran 220 at Speed Week 2000 in XF/BFL class.
I tried filling the block to within 1" of the deck, then running long
course. Temperature-wise it seemed to work OK in the Ardun, but I wasn't
dealing with exhaust heat in the block. It was this application that I had
the leakdown problem with.
Ardun Doug King
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