I hope he has taken all of the necessary variable into consideration.
Those being piston highth expansion due to heat (from wrist pin to crown
of piston. It really will increase with heat!), Rod stretch due to RPM,
rod length increase due to heat expansion, stroke increase due to crank
heat expansion (it really does increase!).....and god forbid, Clearance
for the over revved valve float ! Of course this last one can be
compensated by machining valve pockets into the top of the piston that
will take into consideration, all of the above variables, including the
calculated amount of valve float that you wish to include, depending on
how the engine is to be used.
All of the above variable can Easily eat up a mere 30 thousands of an
inch in a hurry! A motor built to turn 7,000 RPM will have some
significant rod stretch depending on the materials used for the rods,
and the weight of the pistons/pin.
If anyone is planning on building a very hot engine, take the time to
seek out the local area (major city) speed shops and talk to the guys
that are building the top fuel, funny car, Pro Eliminator, NASCAR, or
tractor pull engines. The information you can get is invaluable.
Rich
>----------
>From: marrone@wco.com[SMTP:marrone@wco.com]
>Sent: Tuesday, April 30, 1996 12:46 AM
>To: tigers@autox.team.net
>Subject: Out of the hole
>
>
>>Having the
>>pistons protrude into the gasket area is not a problem as long as you have
>>at least 0.030" clearance between the piston at TDC and the installed head.
>>This would have given you both more compression and more squish at the top
>>of the stroke which helps prevent pre-detonation. Since most thick
>>headgaskets don't squish down to less than 0.040", you might have been OK
>>with the uncut pistons.
>
>>Tom Hall
>
>You like it when you can just make out the marks on the face piston in
>the
>flat part of the cylinder head, or so I've been told. That is probably
>pushing it for most of our applications but it would probably run good
>as
>long as it lasted.
>
>
>
>
>Frank Marrone MK I Tiger B9471116
>marrone@wco.com 1966 LTD
> Series I Alpine (2.3L powered by Ford)
> Yamaha Seca 900
>
>
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