Re: ihc-digest V6 #897

["John Stricker" <jstricke@domain.elided>]

Gosh,

How did I ever run Drag Boats, Tractor Pullers, and Gassers all those years
with "zoomies" and not warp my valves??  And all that dyno time, simply
miraculous.  I must have been extremely lucky, for about 15 years.  ;-)

So tell me, how many valves have you actually SEEN that were "warped"
because of this?

John Stricker

jstricke@domain.elided

"I didn't spend all these years getting to the top of the food chain
just to become a vegetarian"

: Date: Fri, 11 Jun 1999 20:11:30 -0700 (PDT)
: From: Ted Borck <tborck@domain.elided>
: Subject: Uncorked exhaust - warped valves
:
: > Date: Thu, 10 Jun 1999 22:07:32 -0700
: > From: "Owen" <renarac@domain.elided>
: > Subject: Re: Uncorked exhaust
: >
: > True. It will eventually burn the exhaust valves.
:
:
: If the exhaust pipe is short enough to allow [relative] cooler air to
: reach the *hot* exhaust valve(s), the exhaust valve may warp.
:
: A warped valve will not seat properly.  Valves (especially exhaust)
: are cooled by heat transfer upon intermittent contact with the valve
: seat.  Sodium is also used (in high output engines) to [internally]
: cool exhaust (and sometimes intake) valves.
:
: The portion of the exhaust valve face which doesn't contact the valve
: seat will not be cooled by contact with the [relative] cooler valve
: seat and thus burn in that area.
:
: Once *hot* exhaust gas blow-by occurs in the area not contacting the
: valve seat, the situation gets progressively worse
:
: If you're worried about short exhaust(s) causing valve warp, just
: stuff a rag in the open exhaust pipe upon shutting down the engine.
:
: Then go get your ear plugs for the next run. <g>
:
:
: > - ----- Original Message -----
:
: > From: Tom Mandera <tsm1@domain.elided>
: > To: <ihc@domain.elided>
: > Sent: Thursday, June 10, 1999 10:27 AM
: > Subject: Uncorked exhaust
: >
: >
: > > Just remembered..
: > >
: > > I've been told NOT to run a motor w/o an exhaust for long, or you'll
: > > burn the valves?  Something about the too-cool ambient air rushing up
: > > the manifolds and into the heads when you shut the the motor doww, and
: > > causing "bad things."
: