1931 Model A Fuel Question

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xkeots

Member
Hi All,

First I want to say that I pretty much beat Sandy!
My 31 is running great again. I replaced all electrical, ripped out interior, new clutch, all fluid areas were washed out with kerosene 3 times then Ford oil, and all new brakes and wheel bearings.
I need to know what grade fuel is correct for it?
I have regular in her now and it is not as strong or running as smooth as it should be. I used to use High Test but I only had regular in a can.
Which is the correct grade?

Thanks
Jack
1931 5 window coupe
 
I have never used anything but regular when I bought fuel, but have used diesel-gas mix when it was free.
 
To use anything but regular in an original set-up engine is probably a waste of money.

Modern cars with their "knock sensing" computer can get some additional mileage out of higher octane gasoline, but the pricing of super is calculated to be about in the degree of mileage advantage - your cost per mile is probably identical be it regular or super.

Super gas may allow some additional benefit for a high compression head (I'm thinking upwards of 7/1 compression or beyond) but one has to be able to advance the timing slightly beyond the stock engine to achieve this. For most available heads and timing for the Model A, the additional octane capability goes unused.

This octane benefit limitation primarily caused by the "D" head valve arrangement of the Model A.

Small lawnmower engines are now mostly sold not with "D" head type but rather with overhead valve arrangements which allow increase of the compression ratio, allow more advanced timing (although not usually variable as they're set by the induction coil/spark system) and eke out additional horsepower/efficiency beyond what the D head will allow without knock.

The downside of these new lawnmower engines is they're more power intensive, wear out faster, and present problems of narrowed range of successful operation. It is not even possible to adjust the carburation on these engines. And they're racehorses - but they're "touchy."

But they use less fuel, create less pollution, are not user serviceable (and create work for parts and service organizations) and as such are favored by your EPA.

I tend to prefer "user serviceable." Hence my interest in a Model A Ford. You too likely.

Joe K
 
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I use non-ethanol and it is 90 octane. Probably a higher octane then is needed, but being all gas, we {me and my "A"} will just have to handle it.:eek: Plus it cost more too.......:(

Bob-A:D
 
Mitch//pa said:
i use orange juice sometimes in an emergency
Click to expand...
????, Son, VODKA + OJ= A "SCREWDRIVER":eek: but I doubt if the car would run on it. Wonder if it would run on straight Vodka???:confused:
Ran my truck on a gallon of Coleman fuel once to get to the station, PING, RATTLE!!!!!! & wouldn't shut off to refuel!!!!! It was an old Datsun Pickup with a Mustang V-6 & C-4 automatic. Bill W.
 
I have a 1928 trade journal that has an article telling about how wonderful the new gas was.It was 67 octane.Look at the old ads that brag about it.One even used it in their name,Phillips 66.So the el cheepo 87 octane now is like super-super high test for the A's.Leaded fuel was invented,but not in use in the real world for years after that.
 
The lowest octane gas is all you need in an A.With higher octane fuel,you are just throwing your money away.Even with the 5.9 head,I use the same gas as it is still a low comp engine.
 
Yup, as others said, Regular is fine. Think about how poor the fuel quality was compared to what we have today. Transported in small tanks, many miles and weeks from the refinery. Sold in small lots, sometimes from drugstores. Tanks typically above ground, non lined. Plenty of opportunity for water and other contaminants. No manufacturing "standard" for fuels either. With its low compression engine, the Model A would run pretty much any liquid that would burn.
 
During the WWII fuel rationing, my uncle drove his Model A on kerosene. He had a "swap over valve" and would start on gasoline, and then swap on the fly to kerosene.

Gasoline was scarce and rationed - kerosene was plentiful and unrationed.

And he was a young man with a car and dates to go on (medical deferment - and he was one of the few semi-able bodied males left at home.)

Heh. Some guys get all the luck.

Joe K
 
Our old John Deere B and my International H would start on gas, when warm, you switched it over to Kerosene. We never did it though. It was after the war and it was a PITA to keep Gas and Kero just to save a couple of pennies per gal.
Terry
 
A lot of the motors ran on Kerosene back then. I had a 12HP Briggs on an Army Surplus Generator with 2 tanks on it. One for Gas and one for Kerosene, also called "Coal Oil".
 
yea the standard a engine has somehting like a 4:1 ratio while modern cars are 9 + :1

anythign that will burn will do

octane rating has nothing to do with quality of gasoline, the higher the rating the more compression it can handle before self igniting. hence why race cars with a 13:1 ratio need 100 + octane or just the heat from the engine and compression will ignite the mix well before its supposed to.

thats why diesels are up in the 20:1 range and just need glow plugs. dont need an open spark, just heat and compression.
 
Joe K said:
During the WWII fuel rationing, my uncle drove his Model A on kerosene. He had a "swap over valve" and would start on gasoline, and then swap on the fly to kerosene.

Gasoline was scarce and rationed - kerosene was plentiful and unrationed.

And he was a young man with a car and dates to go on (medical deferment - and he was one of the few semi-able bodied males left at home.)

Heh. Some guys get all the luck.

Joe K
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Joe, have you ever read that the real purpose of the gas rationing was not to save gas, but rather, to save tires?
 
100_0506blackout.jpg

thought i would repost this, ww2 ration card for my 29 AA
 
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