I didn't have an option - my head was cut almost .250. I wouldn't even
attempt to run flat tops.
IF I knew I would be installing a NOS head I would have bought flat tops.
Mike
----- Original Message -----
From: "Stan Chernoff" <az589@lafn.org>
To: "datsunmike" <datsunmike@nyc.rr.com>; <datsun-roadsters@autox.team.net>
Sent: Tuesday, August 27, 2002 9:45 PM
Subject: Re: economics of stroker parts
> 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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