Skip;
Regarding exhaust valves-- the valves are off their seat a good deal of the
time, sitting right in a high velocity hot gas stream. The valves are small
and heat up quickly; they dissipate heat through their valve stems (that's
the reason behind sodium- filled valves) and also into the valve seats when
the valve closes.
The conditions for a piston are completely different.
Regards, Neil Tucson, AZ
-----Original Message-----
From: land-speed-bounces+neil=dbelltech.com@autox.team.net
[mailto:land-speed-bounces+neil=dbelltech.com@autox.team.net] On Behalf Of
Dave Dahlgren
Sent: Thursday, October 02, 2008 8:06 AM
To: Bryan Savage; karlepayne55@yahoo.com
Cc: land-speed-digest; jgmagoo@comcast.net
Subject: Re: [Land-speed] 1750 EGT>From>JGMagoo
The thermal loading is very simple... In contact with the piston made of
aluminum that dissipates heat very well are the following.. Cylinder walls
at probably 180 to 200 degrees, oil a little bit warmer, piston pin and
connecting rod, more important air and fuel during overlap.. With all this
going on it is pretty hard to melt a piston unless the tune-up is a mile off
the fuel completely inappropriate. Sure you can hurt one but an egt of 1750
is not the real problem. By the way most good turbine wheels are ceramic now
and pretty tough to hurt, saying that you can break anything if you have
your mind set on it.
In Skips case I think if he put a blower cam in the engine most of his
problems would go away...An intercooler would be a real plus as well..
Dave
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