Pistons made in China and expected to operate at 2000 rpm in engines with
an 8:1, or lower, compression ratio are not necessarily designed for
operation at 6000+ rpm with 10:1 compression ratios. There is more to
consider than looks. Material selection, casting density and autothermic
strut design along with other factors must be considered when making or
selecting performance pistons. The Nissan flat top pistons made for the
U-20 will take the kinds of stresses that will be generated by a stroker R
type engine or the U type.
People in the manufacturing business must be cost competitive and focus on
the market that is buying their products and on the application. Good
business people make products that meet their customers requirements but
not exceed them to a ridiculous degree. Economies of scale are significant
in product cost especially when the product design is focused on the end
use requirements. Even Nissan designed components for their specific use.
An example is the 3-main crankshaft for the H-19 engine since some were
castings and some were steel forgings depending on their application. The
steel forgings were made for the higher performance applications and can
make a 3-main R engine into one with the same displacement as a U-20
(Stroker). Compare an H-20 crank to a
U-20 crank and you will see many differences that have an effect on their
respective performance. You may also note that the U-20 has an harmonic
balancer, that the R and H engines lack, that was not put there to waste
money.
Dished or recess top pistons are not performance oriented. Engine
performance is somewhat proportionally related to compression ratio. The
compression developed by flat top U-20 pistons in an R block with a U-20 or
H-20 crankshaft is not excessive and affords much better performance than
the lower compression dished forklift ones as long as the cylinder head is
not cut excessively.
My R engine with a U-20 crank, rods and pistons and a cyl head cut at least
.100" made it to and from Shasta in the 110+ deg F temperatures without any
cooling or pinging problems while using a 4 row high efficiency radiator
core and the original 4 blade steel fan. It got a little over 20 mpg for
fuel consumption with Solex carbs.
If you are lucky you get what you pay for. Cheap isn't always the best.
Stan
========
At 07:40 PM 8/27/02 -0400, you wrote:
>For a good example of your theory see definition of Chevy Small Block.
>Manley valves which cost me 20.50 are about $8 each. Pistons? Except for
>forged or HP units are ridiculously cheap and made by respected
>manufacturers.
>
>It makes me sick looking through a Summit catalog. Look at the prices of
>Mopar or Ford engine parts and they cost more.
>
>BTW, the forklift parts are made for industrial use and are more often than
>not, overbuilt for reliability. People use the equipment to make money can't
>afford frequent breakdowns.
>
>Mike
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