MTFCA Forum

Hello. Is 90 octane, non-ethanol gasoline safe to use in a Model T engine?

Thank you.
Mike

Likely safe but why use it? Model T's used an Octane rating of about 40-50 in the day. Concern about ethanol is dramatically overstated. People worry about using it in a Model T but not heir modern car.

That's all I burn in my Model T fleet !

Yes. Just about any gasoline is fine. I burn 10% ethanol regular without issue. The problem with any fuel only comes if you leave it in your tank for many months. I often get asked if the lack of leaded gas causes problems. People are surprised to learn that leaded fuel became available only after the Model T era.

Yep. In the early days there was no lead. When they started putting it in, they charged extra for it. Then in the 70's they charged extra again for NOT putting it in.

The model T is a flex/multi fuel vehicle.

Consider using a "modern" Holley NH carburetor as is has an adjustable main jet.

In the period literature, from about 1907 to 1925, there was much discussion on the quality of gasoline being produced. There was much discussion about fuel mixtures including alcohol, ether, and acids. The possibilities of using kerosene was being considered and advice published.

The period between 1915 to 1925 there was a worry about the available of gasoline as it may be in short supply.

And during the life of the Model T, gasoline went from a light petroleum product to a heavy petroleum product.

The model t head went from high compression to low compression. There was a concern about the quality of gasoline, that in 1921, automotive engineers working for General Motors discovered that tetraethyl lead (better known as lead) provided octane to gasoline, preventing engine knock.

Here in California there are 3 grades of gasoline. I use the lowest grade without a problem. Only thing you must use the car from time to time or the gas will get like varnish and plug up the carburetor and fuel line. So try to use it at least once a month to keep things moving.
The state regulates the mixture of ethanol and gas. There are even summer grade and winter grade. Supposed to make less pollution?
Norm

90 octane ethanol-free gas is fine for use in a Model T, and a very good choice for one that is not driven regularly, since it better resists breaking down into a destructive soup of acids, water, and gum. You do not need the higher octane for a T, but having it will have no effect on the T engine, good or bad. Detergents found in some better quality gasolines (Tier One) will benefit a T engine by peventing carbon deposits in the combustion chambers. Lower octane non-ethanol gasoline will provide essentially the same benefits, and may cost less. High octane fuel burns just the same as low octane fuel in a low compression engine. It is not "more powerful", more explosive, or in any way harmful. Using non-ethanol gasoline may provide a slight increase in engine power and fuel economy due to a slighty higher BTU content. Assuming you switch from 10% ethanol fuel to 0% ethanol fuel, the increase in power or economy would be no more than 5%, and would probably be probably less. I drive my car a lot, and I am using fuel that "may contain up to 10% ethanol" due to the high price of non-ethanol fuel here. If bad weather or the road salt spewers prevent me from driving the car as often, I will keep the tank full of non-ethanol 91 octane gasoline while I wait for better conditions. If the price of non-ethanol fuel becomes reasonable again, I will use it exclusively.

I use 10% ethanol in my T's during the peak driving season and switch to non-ethanol gas toward the end of the peak season when I know the gas will sit longer than I would like. I have never noticed a difference in performance when making the switch but I had carburetor issues one year when I left the ethanol gas in one of my cars for a little over three months. Never again!

Thanks for the feedback guys.

My cars have not been driven much, and I no longer trust ethanol-laced gasoline after having seen what it did to a fuel system on some power equipment. I found some non-ethanol, 90 octane gas here locally for $3.60 a gallon and put it in the cars and drove each of them today. It just makes me feel a bit better about my gas tank to have the non-ethanol variety in there in case the cars have to sit again.

Kind regards,
Mike

If your shut off valve is good, you can turn off the gas and run the engine until it stops. That will clean out the jets in the carburetor. Then drain the bottom of the carburetor by opening the petcock. Just remember to close it before you open the valve!
Norm

Here in AZ we don't have none ethanol pump gas unless you buy AV gas or racing fuel in the 100 octane range an in the $7-$8 dollar or more. As I understand ethanol is only one carbon molecule different from methanol and there properties are very similar. Using methanol or ethanol as a racing fuel you will find depending on the type of racing you will need 2-4 times the amount of alcohol but will produce more power. So adding 10% ethanol will artificially make a internal combustion engine (ICE) run about 5% leaner and should reduce emissions. Methanol would would do pretty much the same thing but you can't win favor with environmentalists and farmers ( don't get me wrong I love farmers they feed us) If you use methanol you give profit to the mean petrochemical companies.
Some things I have found out, some distributers charge more for gas because they pay more. This is because they buy the gas that comes down the pipeline first. Others pay less because they buy gas that has been in a tank for a long time & they want to sell it before they end up with10 million gallons of somethin they cant sell. So if you are going to keep the gas for a long time you may want to pay a little more for it. If it is going to set either
drain it or treat it. I have found treated good quality gas will last 18 months or more with with minimal if not no bad effects.
Craig.

From these posts, am I correct in assuming that 90 octane gas is considered high octane for you fellows? Here we have 91 octane as the base grade, then 95 and 98 for the high end pocket rockets. Not every fuel station offers ethanol laced fuel, so I have no difficulty avoiding it. I generally sells for a couple of cents/litre cheaper than base 91 octane.

Allan from down under.

91 octane seems to be the highest available in this area. There are at least a couple of ways of calculating the octane rating.Your may differ from the US standard. (R+M ?) Back in the days of Free America, we had a choice of 93 octane "regular", or 98 to 105 octane "premium". Prices per US gallon ranged from around 17 to 29 cents for regular to 23 to 33 cents for premium.

An old mechanic (he was about 60 and I was 14 at the time) It's not the gasoline that goes through your carburetor it's the gas that sits in your carburetor that causes the problems. The easiest way to avoid the problems is when you put your machine, boat, motorcycle up for the winter shut the gas off to the carburetor while the engine is running at temperature and let it run dry add a preservative to the gas in the tank or drain that gas and use it in your winter car. I have followed his advice and it still works my engines crank when I want them to!