<VV> Overdrive Transmissions

MarK Durham 62vair at gmail.com
Fri Oct 30 10:52:38 EDT 2015

Richard, when you were taught that, did they also throw out there that to
run engines at lower RPM's you also needed to change the torque curve
through cam timing adjustments and change the internal components of the
engines, too. Neither of which we have had discussions about and cannot do
on the Corvair engines, the parts are not available and would be expensive
to build.

Granted, as long as you stay in the torque curve for the engine it should
hold up fine. If you lower the rpm's further you get into territory that
has proven destructive to the engines.

Our engines were not designed to run at significantly lower RPM's. I
totally see what you are doing with the three speed gearing and then the
4th gear being an overdrive.

I had a 63 Ford Galaxie with the 352 v-8, three speed column shifter and a
overdrive, that lowered the RPM's duiring down the road travel. It made the
car quieter, and did not seem to bother the big V-8. But our engines do not
have that extra reserve of power, the V-8 basically was idling along under
very little load in overdrive.

While our cars are lighter than the old Galaxie, the Corvair motor is
significantly lower in power therefore does not have the reserve, and if
you lower the RPMs too much, you could get into a torque load situation
that will damage the engine.

For instance, the 62 couple with 102 engine could be damaged by running
around too much in 4th gear in the 30-40 speed range, it would start to
ping, case in point, lowering a engine rpm too much when you do not
properly prepare the engine in other ways may lead to self destruction.

My 2 cents on engines.

Mark Durham
Hauser, Idaho

Mark Durham
Hauser, Idaho
62 Monza coupe Red/Red 4 speed

On Fri, Oct 30, 2015 at 7:37 AM, DickR13607--- via VirtualVairs <
virtualvairs at corvair.org> wrote:

> I understand the rpm problem, but, as an engineer whom worked for  FoMCo
> for a number of years, I was taught that lower rpm's meant better  gas
> mileage and longer engine life.  Also, why have various people spent  years
> working on possible 5-speed transmissions for Corvairs?  I thought my
> idea was
> much less costly.  Would it work?  I don't know, but I  haven't seen
> anything
> that addresses that question.
> Richard Royle
> 66 Corsa Turbo
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