Re: Boring and stroking vs your cylinder head

[RangeR BoB <samurai@xxxxxxxxxxxx>]

If you stroke an engine, you either need shorter con rods (1/2 the
added stroke shorter) with stock pin height pistons, or you need pistons
with the pin bosses (the wrist pin holds the piston to the small end of
the rod) moved closer to the piston crown.  This works to a point, that
point being when you crowd the rings too closely together.

	Typical pistons have two compression rings and an oil ring.  The
grooves they ride in can only be pushed so close together before the
lands between them aren't strong enough and fail.

	Typically custom rods are $$$ and custom pistons less so.  So if you
can't parts bin engineer the right deck height (distance of the piston
crown below the top of the block) then custom pistons can be an answer. 
Cheaper than rods.  Rods may be your only option, tho.  Longer rods tend
to make more power, all things being equal, (another can of worms) so
short deck pistons seem to win all around.

	In the old days, it was a neat trick on Flathead Ford V-8s to get a
Mercury crank, which was the same journal size as the Ford, but 1/4"
longer stroke.  Use stock pistons, they'll hit the head, right?  Well,
turns out the head gasket was 1/8" thick...  So two head gaskets and you
made it...  Not that I would recommend that on a modern engine, but on
6.5:1 compression, it worked fine...
- -- 

 RangeR
   BoB
 Hembrook
 
 '89 BMW 750iL                   	"Sputnik"	94k 
 '89 Suzuki Samurai 4x4          	"Sammy"   	95k
 '88 Kawasaki ZX-10					28k

	All with stock strokes...

------------------------------