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Re: Out of the hole

To: marrone@wco.com (Frank Marrone)
Subject: Re: Out of the hole
From: Roland Dudley <cobra@cdc.hp.com>
Date: Tue, 30 Apr 96 11:06:21 PDT
> >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


I had the pistons shaved for several reasons.  The spec indicated they
were too high, my rebuilder felt they were too high and I prefer keeping
the compression ration down to a reasonable level.  That's also why I
decided to go with larger valve fly-cuts, even though I plan to stick
with the stock size valves.  This won't make a lot of difference, but
from my point of view, it's in the right direction.  I may even have a
little taken out of the chambers if it looks like the CR is going to be
too high to run pump gas, or at least pump gas with a modest amount of
octane booster.  My primary use will be street driving so I'm shooting
for practical performance to the extent possible.

Other considerations:  the block has been decked twice and the HiPo head
gaskets are thinner than non HiPo head gaskets.

The last time I rebuilt this engine I installed big valves, pop-up
pistons and a hotter cam.  I really hated it.  It ran hot, and all the
torque was above 4000 RPM.  The car was more fun to drive stock.  Even a
stock Cobra has gobs of power for the street, and with 6" wire wheels, I
doubt more is needed.

Roland

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