<VV> 140 heads

[Roger Gault]

Remember the "pump" is now broken.  If you drop an intake, the hole is
always open.  There is no normal flow through the cylineder.  When you see
pressure in the exhaust manifold or vacuum in the intake (which is pretty
much all the time), and the exhaust valve in the bad cylinder is open,
you'll get reverse flow.

Also, the valve is still thrashing around at high speed, batting bits of
broken seat all around.  Some will probably go upwind.

It doesn't take all that many pieces sucked into the other cylinders to make
a mess.  Catch one at the edge of the piston and collapse a ring groove, and
you get to buy a new piston - been there.  Even if you don't do
un-repairable damage, digging all those little hard pieces out of the
aluminum and trying to smooth it back up is a real pain.

Roger

PS:  I once saw a Lycoming O-720 (big honking [720ci]  8 cyl boxer engine in
a Piper Comanche) drop valve pieces down into the common intake below the
engine on landing approach and then suck them back up into all 8 cylinders
on takeoff after the bad cylinder was replaced.  One valve dropped = 9 new
cylinders/pistons.  $$$$


----- Original Message ----- 
From: "Andy Clark" <slowboat at mindspring.com>
To: "VV" <virtualvairs at corvair.org>
Sent: Tuesday, January 30, 2007 11:29 PM
Subject: Re: <VV> 140 heads


> Hmmm....how does that happen? I would have thought that the fluid dynamics
> would tend to send the pieces towards and out through the exhaust valve
for
> that cylinder (the ones that don't get stuck in the top of the piston).
> Andy Clark
> Camano Island, WA.
> 1966 140/4 Monza Sedan
> 1966 140/4 Yenko Clone
> 1966 180/4 Cord 8/10 #60
> ----- Original Message ----- 
> From: "Frank DuVal" <corvairduval at cox.net>
> To: "BBRT" <chsadek at comcast.net>
> Cc: <virtualvairs at corvair.org>; <KELLYJRE at aol.com>
> Sent: Tuesday, January 30, 2007 7:30 PM
> Subject: Re: <VV> 140 heads
>
>
> > Just goes to show racing is different than driving! gggg
> >
> > Over the years I have replaced more intake seats than exhaust seats.
> > Even more better is when the intake seat shatters and the pieces are
> > sucked into all three cylinders on the head...
> >
> > Frank DuVal
> >
> > Correct above to say machine shop replaced for me...
> >
> > BBRT wrote:
>
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