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Why is it always #5?
Posted by: Caveman_1960 ()
Date: December 20, 2017 05:26AM

Perhaps some of you smarter guys out there could shine some light on this observation: Seems to me that whenever one of the Corvair engine's exhaust down tubes rusts out, #5 exhaust tube goes first.

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Re: Why is it always #5?
Posted by: Brizo ()
Date: December 20, 2017 06:24AM

My theory has always been -- #5 is closer to the shroud opening where the seal flap around the manifold was probably gone. The right rear tire would often run through puddles along the side of the road, splashing water(and road salt) on the exhaust tube. ?

Dan Brizendine,
'64 8door Greenbrier 140 PG. "In beautiful Wanamaker Indiana...with one stop light and 5 pizza shops"

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Re: Why is it always #5?
Date: December 20, 2017 07:33AM

In the forward position, #5 does not receive as much of the benefit of the built in flow of the lower oiling system in the push-rod tube/head interface. smoking smiley
These days folks tend to seal up that designed in oil flow with viton....

Dan Brizo shoulda been a Corvair design engineer. thumbs up IMHO he rusty nailed it.


Dan Davis ~ Pierce County, WA ~ CORSA Western Director + Corvairs NW + North Cascades Corvairs + Corvanatics
1966 Corsa Turbo coupe ~ ~ 1966 140 Corsa ~ ~ 1965 Monza 140/4 'Vert Sierra Tan/Fawn ~ 1964 Monza 'Vert (SOLD) ~ 1960 Monza Ermine White/Red PG ++ ~ 1965 Monza 140/4 Evening Orchid w/ ivory/black interior ~ 1962 Monza Wagon 102/4 ~ 1963 Rampside/Scamper ~ 1963 Red/Greenbrier ~ 1969 Ultra Van #468



Edited 1 time(s). Last edit at 12/20/2017 07:43AM by 1966-Corsa-GT-180.

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Re: Why is it always #5?
Posted by: MattNall ()
Date: December 20, 2017 07:38AM

I think the Exhaust tube suffers the same as the cylinder...always runs slightly hotter...causing the deterioration of the tube as well.





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Re: Why is it always #5?
Posted by: steve c goodman ()
Date: December 20, 2017 07:56AM

MattNall Wrote:
-------------------------------------------------------
> I think the Exhaust tube suffers the same as the
> cylinder...always runs slightly hotter...causing
> the deterioration of the tube as well.


Steve agrees and also adds: #5 seems to have the worst
track record of seat ring failures too, particularly
on 140hp heads. Followed closely by #2, same cyl
but the head is turned around suffering from extra
heat by oil cooler.

Plus as Brizo stated above about the air outlet
seal being poor, the ducting of air over the oil
cooler probably takes air away from being forced
downward through the end of the head.

NOTE: lots of 'seems' and 'probably' in my above
guesses.

best wishes, Steve
Rear Engine Spec. Inc. Golden, Colo.

1962 spyder 3.0L turbo 1965 Crown V8
1967 monza 110/4 1968 monza 110/4
1971 amante gt 110/4
CORSA/RMC/PPCC

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Re: Why is it always #5?
Posted by: JimBrandberg ()
Date: December 21, 2017 04:16AM

Regarding exhaust tubes I'm with Dan and the exposure to the elements theory especially with road salt.
Regarding valve seats I'm with the faulty fresh air hose theory.
Just my opinion and I could be wrong.
Jim Brandberg
Isanti, MN
Corvairrepair.com

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Re: Why is it always #5?
Posted by: 63turbo ()
Date: December 23, 2017 02:23PM

There's a hole in the shroud that is approximately .4"... maybe bigger, and
it is located next to the #5 and #2 cylinder spark plug holes. There is also
a boss under these holes to cover them but they do seem like spots that would
cause leaks. Has anyone tried actually sealing those holes? It's interesting
that the 2 cylinders that run the hottest would have air leakage spots.

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



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