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Re: [turbobike] Re: SOHC Honda headgasket problems ' et al'

Jeff Churchill (jcperformance@juno.com)
Sat, 22 May 1999 13:19:36 edt

   The expansion rate of copper is immaterial.  Headbolt/cylinder stud
'stretch'  is the holding power.  Oil will wick past copper no matter the
sealer,...retorqing  is only necessary with fiber type materials that
compress beyond a certain point.  That is the main reason for multiple
shim type steel gaskets.  Some sealer is commonly used with fiber type
gaskets,....but of questionable value,...can't hurt.
   A chemical can never do what a mechanical seal does ( I'm not talking
thread sealant)
   Probably 99%  of head sealing problems not of an initial mechanical
nature, are caused by detonation,......period.   Take this to the bank. 
Turbo motors not detonating can produce unbelievable power with stock
components,...and reliably.  You MUST have close fuel mixture and 
ignition timing controls to keep combustion normal.  You can calculate
proper timing exactly from ideal normal and boosted induction pressure.
   Do you ever wonder how  11:1 compression  28 psi boost motors live ?  


Jeff Churchill

J.C. Performance    617-06  Bicycle Path   Port Jefferson Station   NY  
11776    USA
tech:  516-928-6679  or  516-928-9863
website:     http://www.jcperformance.com/

On Sat, 22 May 1999 02:02:36 -0400 (EDT) MCycleTech@webtv.net (Eric S.)
>Two cents from the peanut gallery. I agree with all the input, and 
>that I know jack about T/Supercharged systems first hand. Another
>thought included is copper has a quicker expansion rate than say your
>cyl. "barrel's". And temp. ranges from parked warm up, to operating
>conditions, dynamic cooling, etc., call for retorquing. Not to 
>extreme conditions. Ideally no sealer is required for apps. like head
>, if condit. & materials are on the money. But I would imagine 
>"tackier" for sealing like SUZUKIBOND 1207B (or equiv.)  would be 
>durable than Y.B. 4 or 5, the latter being forms of semi-curing 
>that cannot hold comp. press. as adequate. Multi-layer treated steel
>gskts (like newer GSX-R's) are ideal (tuneable C.R. a plus) but as
>somebody said, are prob. not available. BUT LIKE I SAID, IT'S ALL
>THEORY!!! I'll try to do a little research on it. GOOD LUCK!