[FC] Rampside detonation (pinging)

[vernmcintosh at eoni.com]

Mike wrote,

>I also have a 140 with a PG in my rampside, and have
>not had any trouble with it dropping seats. This is my
>everyday driver. The only downfall is that I don't think
>it was worth the trouble to do the swap as the
>performance increase compared to the 110 that I
>had in it was that radical to have made the change
>worth while.

And Ken wrote,

>In your PG Truck, did you put a manual trans 140  in?
>A 140 with a PG needs to have the PG 140 engine
>installed in order to see the performance gain below
>40 MPH. I have owned several 140 PG cars and they
>do run slightly better than a 110 will, even off the line.

Vern writes,

I have the opposite in my truck, a 140 PG engine (2 carbs) and a 4-speed.
The low-speed, around-town performance is dramatically better than my
daily-driver 110 Corvan, but the trade-off is, as to be expected, less power
at highway speeds.

I learned early with this combination, by collapsing a set of TRW pistons,
that I needed some assistance with managing the engine, that audible ping is
not necessarily an adequate indicator of detonation. (a moot point in a
Rampside, since you can't adequately hear what is going on back there
anyway).

I installed a Ray Sedman SafeGuard with a dashboard LED readout. With
ordinary driving, I allow the SafeGuard to 'do its thing' of retarding the
spark to individual cylinders as knock occurs and I ignore it. On the
highway I use the indicated activity of the SafeGuard to decide when to go
to 3rd gear, generally on grades steep enough to have a 'slow truck' lane.
There are simply too many variables of temperatures, engine load, and engine
rpm for me to effectively 'guess' at possible detonation activity. In 3rd
gear, about 50 mph, 3300 rpm produces little or no SafeGuard activity on the
steepest grades, and I still pass most of the trucks.

SafeGuards are not cheap, I could probably not justify the expense if my
truck was a 'hobby truck' alone instead of also transportation. I consider
it good insurance for engine longevity and for disaster-prevention far from
home.

BTW, in 39 years of Corvair-only driving, I've never dropped a valve seat.

Vern McIntosh
Bend, Oregon