Re: [Amc-list] performance, Rambler-Mentality style :-)

[Tom Jennings <tomj@xxxxxxx>]

On Thu, 29 May 2008, farna@xxxxxxx wrote:

> keep cruising speed down to 55-60, but I routinely ran my 63
> American w/auto trans, 3.31 gears, and 196 OHV/2V 65-70 mph
> and still averaged 19 mpg combined city/highway driving. The
> 196 does sound like it's working hard at around 2500 rpm, but
> it will run all day like that.

With all this talk about mileage, I started wondering why mine
it's higher. One thing is entirely my doing: I lug it all the
time. This motor is very happy pulling hard (OK that's relative
:-) at 1800 rpm.

Ken and others mentioned their vacuum guages, and I forgot to
notice that I was basically ignoring mine; my driving habits had
it deep in the red (less than 10 InHg) much of the time, because
the torque curve is essentially flat from  1500 rpm through 3500.

Yesterday I started Ken's technique -- vacuum above 10 InHg
at all times. I was probably driving < 10 a third of the time;
now it's a tenth, mostly dead stops, freeway merges, etc where
I'd be in the way. Coincided with a fresh fillup so a week or
two I'll have a couple of tankfuls through it.

> I hardly ever ran it any faster
> than that for any length of time. You might want to get a small
> tach, at least temporarily, to see what rpm you're running. I'd
> definitely go with a Pertronix conversion too!

Part of my problem is the nice old tach I have installed --
I got it from the Barney Navarro auction, and it's got a nail
polish redline marked at 6500! -- is way off! It reads 300 -
400 rpm high! Duh. Tach says 2300 at 60 mph, which should be
67.4mph. It says idle is 1000 -- no way. I'll check it with
my digital tach this weekend. I can see no way to adjust the
crimped-case tach.

So I'm revving higher overall, watching the vaccum guage,
up shifting at 3000 - 3200 when there's a load. I have good
records so I'll notice any difference.


> net you 1-2 mpg just from more consistent fire. A hotter coil
> (factory Ford electronic ignition coil, or Pertronix) would be
> of benefit too. The stock points coil is 30-35K volts, stock
> electronic ignition 45-50K. Then run a slightly wider plug gap,
> same plugs. 0.035-0.040 gap.

I chickened out and bought the Pertronix epoxy coil. THe old
American has no ballast resistor nor resistance wire in the
harness, so you'd need to add a resistor for the Ford coil. I was
also worried about wire guage and old crimped connections. The
Ford TFI coil draws a LOT of current. The epoxy coil fits in
the bracket. It's much higher output than stock, claimed, I forget
the specs.

The TFI coil would be great though, all you'd need is a fatter
wire and ballast resistor (1 ohm, some generic NAPA part).
I run stock gap. Compression and speeds are so low that I can't
imagine there's really that much need for monster spark to fire
off the cylinder. (The ford TFI coils are like $100 from NAPA,
but $5 from junkyards!)

> Tom, I've got an article on those Mobil Economy runs. Those
> guys didn't run over 40-45 mph, used the free-wheeling feature of
> the OD religiously (let off the gas when going down hill -- w/OD
> if the driveshaft turns faster than the engine it free-wheels to
> prevent over revving the engine), and took off slowly, getting
> into high gear as soon as possible. So drive slower than a
> 90 year old grandma and you too can get up to 30 mph in your
> Rambler! It's just not practical to drive the way those guys did.

45mph! Yeah OK, I bet I could get 25mpg+ on some flat long and
level Nebraska freeway at 45mph!

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