<VV> Why #5 Throws Valve Seats, was Fresh Air Vent

[N. Joseph Potts]

I'd like to offer an alternative theory as to why cylinder #5 so frequently
throws the big (on 140s) valve seat.
     The theory relies on the observation that it is about equally common
for #2 to throw a valve seat.
     The cylinders on the Corvair are staggered from one bank to the other.
#5 and #2 are the "extreme" cylinders, in that they are farthest from the
blower. Go look at yours, and you'll see what I mean. I believe these two
cylinders are thermally stressed more than the other cylinders because of
this. Or, more specifically, I mean those ends of the heads. The opposite
end of each head is substantially closer to the blower, and valve seats
throw less frequently on the less-extreme cylinders #1 and #6.
     Partly because I never need heat in the passenger compartment here in
South Florida, I keep my fresh-air output blocked and an intact hose
attached to it and to the heater box.
     What's your name, OpenHabit?

Joe Potts
Miami, Florida USA
1966 Corsa coupe 140hp 4-speed with A/C

-----Original Message-----
From: virtualvairs-admin@corvair.org
[mailto:virtualvairs-admin@corvair.org]On Behalf Of OPENHABIT@aol.com
Sent: Saturday, July 10, 2004 8:38 PM
To: virtualvairs@corvair.org
Subject: <VV> Fresh Air Vent


> SNIP: People block the air outlet because they are too lazy to replace the
air hose to >the heat control box.

All right, this has become serious.
The hole at the back of the "Turkey Roaster" is referred to as a "Fresh Air
Vent." Experience has shown that it can rob cooling air from the number five
cylinder. I have known a few people that have lost a valve seat from number
because of this. I don't want this to happen to my car, so I block it to
keep the
cooling air flowing over that colander. I usually run a nice new hose
connected up, so the stock people won't have a cow. It has nothing to do
with my being
lazy. I am lazy enough without that aspect.

Openhabit