[Land-speed] high speed engines/tight clearances

[Ed Weldon]

Neil -- I think you're on to something there.  Adding silicon to aluminum
alloys reduces their temperature coefficient of expansion (CTE).  Raw
aluminum is about 13 millionths of an inch per inch per degree Farenheit
(F).  Common 356 casting alloy is 11.7 millionths.  Tuning block and piston
alloys to the right CTE just requires some patience on the part of
metallurgists and the foundry crew.
We've got the measuring and machining capability to hold 25 millionths
tolerances on 2" to 3" diameter bores (not cheap).  I can see where holding
piston to bore clearances tight enough to control oil and hold a good
pressure film to prevent high friction metal to metal contact would allow us
to go with only one and maybe even no compression ring.  Take a bit of
expensive engineering effort; including temperature control in the operating
engine; but that's just part of the F1 game (and no doubt a source of pride
in western EU engineering cultures).
Ed
----- Original Message ----- 
From: <neil at dbelltech.com>
To: <jgmagoo at comcast.net>; "'land-speed-digest'" <land-speed at autox.team.net>
Sent: Wednesday, April 30, 2008 3:29 PM
Subject: Re: [Land-speed] VE, etc.>From>JG Magoo
>fond remembrances of a Dooling .29 running on "bug juice".
> Some of these little engines had extremely tight piston/cylinder
clearances
> so that rings could be eliminated completely. The pistons were lapped into
> the cylinders to get those tight clearances. I wonder if F1 engines are
> doing that; it would eliminate some friction and the high RPM ring
problems.
> Regards, Neil   Tucson, AZ
>
> -----Original Message-----
> From: land-speed-bounces+neil=dbelltech.com at autox.team.net
> [mailto:land-speed-bounces+neil=dbelltech.com at autox.team.net] On Behalf Of
> jgmagoo at comcast.net
> Sent: Wednesday, April 30, 2008 2:48 PM
> To: land-speed-digest
> Subject: [Land-speed] VE, etc.>From>JG Magoo
>
> (snip)........ normal room temperature (say 70-F) a
> Formula One engine is completely SIEZED, and will NOT turn over with the
> starter. It is only after a period of time pre-heating it by pumping 180-F
> water and 180-F oil through it that it reaches proper internal clearances
> where it can be turned-over and started by the starter apparatus.   Wow!
> ;o) ......... JG