What gas to use in my prewar car?

[RVMC]

Hey Everyone,  just wondering what gas to use in my 1930 LaSalle?,  I'm hearing a lot not use ethanol in my fuel system.

[EmTee]

I would use non-ethanol gas if it's available in your area.  You should still 'ethanol-proof' the fuel system, however, if you plan to drive the car on trips or tours where you may be forced to fill up with 10% ethanol...

[edinmass]

Depending on your location, the vacuum tank will dictate what you can run. Run non ethanol if at all possible. If you run an electric fuel pump, it will burn with the Cad-Johnson carb……so carry four fire extinguishers.

[Rusty_OToole]

Non ethanol if available, and the lowest octane you can get. Gas was about 60 octane back then compared to 87 for the cheapest regular today. Also, add some Marvel Mystery Oil, Redex, Bardahl or your favorite upper cylinder lubricant. Today's gas is too dry. Some find that adding up to 25% kerosene makes their twenties or thirties car run smoother, cooler and develop more power also stops vapor lock.

[Durant Mike]

14 hours ago, Rusty_OToole said:

Non ethanol if available, and the lowest octane you can get. Gas was about 60 octane back then compared to 87 for the cheapest regular today. Also, add some Marvel Mystery Oil, Redex, Bardahl or your favorite upper cylinder lubricant. Today's gas is too dry. Some find that adding up to 25% kerosene makes their twenties or thirties car run smoother, cooler and develop more power also stops vapor lock.

Hand not heard about using 25% kerosene in the 20's or 30's cars very interesting. Use this instead of Marvel?

 

[edinmass]

1 hour ago, Durant Mike said:

Hand not heard about using 25% kerosene in the 20's or 30's cars very interesting. Use this instead of Marvel?

 

25 percent is ridiculous…………if your having that much trouble with vapor lock, run a return fuel line. On hundreds of cars so far, I haven’t even had to go there. How one deals with modern fuels…….notice I didn’t say gasoline………depends on a bunch of things. Dealing with it isn’t necessary difficult or expensive………but it is often time consuming. With a few small exceptions a low pressure electric fuel pump is all you need. Setting it up correctly is another long conversation. 
 

PS- those cheap Chinese 25 dollar fuel pumps are only worth five bucks, maybe. Buy a good Carter……and do it right.

[Terry Harper]

We avoid ethenol fuel simply because its hygroscopic meaning it absorb moisture from ambient air. In your everyday driver this isn't much of a problem because its cycled through fairly rapidly. but in a vehicle that sits for long periods of time with a partially full tank it is indeed a problem. In addition ethenol fuels breakdown much, much faster than non-ethenol gasoline. This means separation and of course varnish and sludge. 

 

 

[JRA]

On 4/22/2022 at 3:30 PM, edinmass said:

25 percent is ridiculous…………if your having that much trouble with vapor lock, run a return fuel line. On hundreds of cars so far, I haven’t even had to go there. How one deals with modern fuels…….notice I didn’t say gasoline………depends on a bunch of things. Dealing with it isn’t necessary difficult or expensive………but it is often time consuming. With a few small exceptions a low pressure electric fuel pump is all you need. Setting it up correctly is another long conversation. 
 

PS- those cheap Chinese 25 dollar fuel pumps are only worth five bucks, maybe. Buy a good Carter……and do it right.

Unfortunately I have no option, in Brazil the available gasoline has 27% of ethanol, so vapor lock and overheating are always an issue. I have never tried to add kerosene. Considering this high level of ethanol, do you think it is worthwhile?

[edinmass]

It would help. You can also filter the ethanol by passing it through a pump/filter set up. You can then put the product that you filter in E85 cars so you don’t lose the fuel expense. They make portable units that are available commercially.  

[JRA]

Thanks Edinmass. I will test the addition of kerosene to see the effect in my cars.  I thought this mixture would have a lower boiling point, once kerosene is lighter than gasoline, so the overheating problems would become worse.

I did not know such filter/pump, how does it work? Is it to separate gasolina from ethanol in an external tank or in the car fuel system? If you have brands or models info to share, it would be great!

many thanks!

[Stude Light]

Although a bit more expensive, I thought about trying naphtha in my fuel mix just to get it down into the 80 octane range (about 10% naphtha). Not as oily as kerosene. I had a little smoking when using kerosene.

[edinmass]

The systems are commercially available, I have seen units that will do 25 gallons for about 1500 dollars us. Just search them out on Google.

[Rusty_OToole]

We had some discussion on this point last year. One contributor said he used 25% kerosene in his 1932 Buick which had about 4.5:1 compression ratio with good results.  I might try 10% in a prewar, low compression car especially if it had overheating and vapor lock problems. The upper cylinder lube is proven to reduce valve and ring wear by half.

[Bleach]

I talked to a guy who had a '26 Dodge and he would add some motor oil to his fuel. He said the modern fuel once seized his engine so he always added oil after the expensive rebuild. I wonder if using some two-stroke oil would work since it seems to mix easier with gasoline? I've used 2 stroke mixed fuel in my lawn tractor when I'd run out of regular fuel. It didn't seem to smoke all that much.

[Rusty_OToole]

2 stroke oil is good. You only need a little, maybe 250ml to a full tank of gas.