Premium Gas for Prewar Cars?

[TexRiv_63]

Recently I have seen three or four post references to using premium gas in older (20s - 30s) cars in which this apparently solves some of the driveability problems inherent with the ethanol blends of most modern gas. I know the octane is not an issue since the compression ratios are so low but is there really anything to this? I'd like to hear from anyone who has tried it and noticed a difference.

[Rusty_OToole]

Premium gas is what you DON'T want.

The only advantage to premium gas is the higher octane. Higher octane gives more resistance to knock in a high compression engine. Nothing else.

Any engine will run best on the octane fuel that it is designed for. An old low compression engine will run better on LOW octane fuel.

Some owners of low compression prewar cars mix kerosene with the fuel. They report easier starting, smoother running, more power, cooler temperatures, and better mileage.

One person on this board stated that he drove a 1932 Buick for many thousands of miles on a mixture of 3 parts regular gas to 1 part kerosene. He used the Buick as a tour car in the 70s, towing a trailer. It ran great, had lots of power, no trouble at all. The 32 Buick had a compression ratio around 4.5:1.

As a general rule the octane should look like the compression ratio. If you have a sports car with 9.2:1 compression buy 92 octane premium. If you have a regular car with 8.7:1 buy 87 octane. If you have a prewar car with 6:1 compression 60 octane is fine.

Naturally this is not a hard and fast rule just a general guide, but it will give you an idea what kind of fuel your engine requires.

Another thing. Before about 1955 all the gas was low lead or no lead and engines were made to run on low octane low lead gas. It is only cars from the mid 50s to 1970 that require high octane leaded gas.

[Rusty_OToole]

In the thirties Tom McCahill ran a garage in New York city that specialised in high priced import cars. He owned many Rolls Royces in this period, mostly the old Springfield Silver Ghost model.

In those days there were 3 kinds of fuel available. Ethyl or premium leaded, regular, and cheap unbranded straight run gas. The straight run gas had no additives of any kind, and was just one step above lamp oil. It was sold for donkey engines, garbage trucks, and washing parts.

He always used the cheapest gas in his Rolls Royces. They had less compression than a pantywaist handshake, as he put it, and they ran beautifully on it.

[Rusty_OToole]

Do you remember Union "76" and Union "66" gas from the 30s? The 76 was Ethyl with 76 octane for high compression engines with compression ratios in the 7s. 66 was made for ordinary cars with compression ratios in the 6s. The straight run, unbranded gas was in the 50s and was used in Model Ts, trucks, and other low compression engines.

When I pumped gas in the 60s we sold BP "98" and "88" octane gas. If you had a real hot rod with compression ratio above 10:1 you had to hunt up a Sunoco station where you could get "Blue Sunoco" 103 octane.

[ply33]

My 1933 Plymouth with its stock 5.5:1 compression ratio and mechanical fuel pump has had no issues with running the cheapest gas I can find locally. Not that gas is that cheap here in the SF Bay area. Lowest octane listed on any of the pumps here is 87.

I've heard of people having issues with vapor lock with modern fuels but that has not been a problem for me.

[Guest TWIN FINS]

Brand new here. So what gas for post '55 cars. Where can I find high octane leaded gas?

[TexRiv_63]

Rusty,

I had a few cars back in the 60s and early 70s that needed Sunoco "260" which was the 103 octane. I remember the pump had a selector lever on it that mixed the 260 with regular to give out a lot of different octane levels.

Your comments about the old cars are exactly what I had thought but lately I have seen a number of comments about using premium as an offset for the 10% ethanol, I think referring to a slower burn and less percolation. There had been enough comments that I thought there must be something to it.

[keiser31]

Ahhh...Sunoco 260...beverage of champions!! My 1931 Dodge was made for unleaded, so I don't worry about it.

[Dave@Moon]

Brand new here. So what gas for post '55 cars. Where can I find high octane leaded gas?

I'm afraid there's no such animal any more. There are additives that substitute for lead in so far as lubricating the valve seats is concerned, but for most cars that's only an issue with heavy use driving (long distance, mountain, heavy loads). It's best to inquire about a specific car to see if your valvetrain is sensitive to the valve seat recession which can occur in the absence of lead.

As for octane content, use the lowest number that your car doesn't "ping" on. You can usually find up to 94 octane pump gas still available right now, which should be good for most cars below 10:1 compression (and some @ 10.5:1). If your car still has pre-ignition using 94 octane you'll have to go to an octane booster additive.

[keiser31]

The only difference in using ethanol in my '31 is that I had to replace the electric fuel pump with one that would not get eaten up inside by the chemicals in the fuel.

[Guest TWIN FINS]

I'm afraid there's no such animal any more. There are additives that substitute for lead in so far as lubricating the valve seats is concerned, but for most cars that's only an issue with heavy use driving (long distance, mountain, heavy loads). It's best to inquire about a specific car to see if your valvetrain is sensitive to the valve seat recession which can occur in the absence of lead.

As for octane content, use the lowest number that your car doesn't "ping" on. You can usually find up to 94 octane pump gas still available right now, which should be good for most cars below 10:1 compression (and some @ 10.5:1). If your car still has pre-ignition using 94 octane you'll have to go to an octane booster additive.

Alright then, what gas should I use for a stock 361 Mopar wedge V8 in a '58 Desoto?

Bruce

[Owen_Dyneto]

I don't agree with the statement that there no longer is such a thing as high octane, leaded gasoline, I just don't know if it's legal for us to purchase it. 100+ octane leaded fuel is still available at airports serving the civilian light aircraft sector. And the other alternative is that it is still legal to purchase and add tetraethyl lead to your own gasoline, and it's readily available. In either case but especially the latter, pay strict attention to safety measures, tetraethyl lead is VERY TOXIC. At the very least, wear impervious gloves and wash very thoroughly after handling. I add TEL to 93 octane pump gas to satisfy the 10.0 compression of my 56 Packard Caribbean, which also does not have hardened valve seats.

[Rusty_OToole]

Gas laced with Ethanol was sold in the midwest in the 30s. I don't remember all the details, it was in an article I saw on the web.

There were pictures of the gas stations. I think it started with a farmer's co-op aimed at using up farm surpluses and furnishing farmers with cheap fuel.

So it's possible your 1933 car burned gasohol when it was new.

Henry Ford was also a supporter of alcohol based fuels. He stated that a field of potatoes would yield enough alcohol to cultivate the field for 100 years. I don't know if this is true or not but he thought alcohol would eventually substitute for oil fuel.

[Dave@Moon]

I don't agree with the statement that there no longer is such a thing as high octane, leaded gasoline, I just don't know if it's legal for us to purchase it. 100+ octane leaded fuel is still available at airports serving the civilian light aircraft sector. And the other alternative is that it is still legal to purchase and add tetraethyl lead to your own gasoline, and it's readily available.

Tetraethyl lead additives are sill available, but only as restricted for off road use. It has been illegal to be using any fuel containing lead on a public road, regardless of vehicle type or source of the lead, since 1996.

[Guest wombvette]

Alright then, what gas should I use for a stock 361 Mopar wedge V8 in a '58 Desoto?

Bruce

General rule would be the compression ratio times 10. IE. 5 to 1 = 50

6 to 1 = 60 9 to 1 + 90 10 to 1 + 100.

[Dynaflash8]

You can still buy aviation gas for your car, with low lead. It also doesn't rot in 3 months like Ethanol laced gas. My Buicks vapor lock on Ethanol laced gas when then temperatue outside gets much over 80, or if I stop and the temperature goes up in the engine. I can start and leave the gas station and about the time I get into third gear the car starts running out of gas and I have to click on the electric fuel pump. I still have one place in town that sells gas with no Ethanol, for a little while yet, thank goodness. A Merry Christmas would be an edict outlawing Ethanol, but of course our leaders in Washington don't drive old cars.

Edited December 25, 2009 by Dynaflash8 (see edit history)

[Rusty_OToole]

Alright then, what gas should I use for a stock 361 Mopar wedge V8 in a '58 Desoto?

Bruce

If it was mine I would be using regular if it has a 2 barrel, if it knocks or if it has a 4 barrel high compression try the premium. If it doesn't knock the low octane is fine.

I would also toss in a little upper cylinder lubricant or even 2 stroke oil.

[Restorer32]

AMOCO Super Premium NEVER had lead. My understanding is that lead was not introduced into gas until 1937. Much ado about nothing in most cases.

[Guest 8Straight]

I would also toss in a little upper cylinder lubricant or even 2 stroke oil.

That's something I have been wondering about.

What would the advantages and disadvantages be in adding some 2 stroke oil to the gas. I would expect the fuel system rubber and the valves would benefit from it.

[Guest broker-bob]

Jay Leno has commented on his sight about using Transmission fluid in gas as an upper engine lubricant what do you all know about that ????? also I read on Web that some of the products that are added to gas to eliminate valve ware have TEFLON that can clog up the filters-----------COMMENTS ? bobnroman@yahoo.com

[Owen_Dyneto]

Tetraethyl lead additives are sill available, but only as restricted for off road use. It has been illegal to be using any fuel containing lead on a public road, regardless of vehicle type or source of the lead, since 1996.

Dave, can you provide me with a citation from Federal regulations on that? I was under the impression that it was illegal to "dispense" tetraethyl lead containing gasoline. The stuff I buy for the 56 Caribbean contains genuine tetraethyl lead and is heavily advertised in Hemmings Motor News and other sources.

[Rusty_OToole]

You used to get upper cylinder oil in little bitty cans for a quarter. It was made from cottonseed oil or canola oil. I don't know if they added anything else.

There must be some valve protecting products on the market but I don't use them so can't suggest any brand.

[Guest TWIN FINS]

Talked to my nephew over Christmas about a smokey situation I've been having and he suggested a quart of transmission fluid added to the engine was great for cleaning things out, (not type F) but to keep an eye out cause the oil will get dirty quick.

[Dave@Moon]

Dave, can you provide me with a citation from Federal regulations on that? I was under the impression that it was illegal to "dispense" tetraethyl lead containing gasoline. The stuff I buy for the 56 Caribbean contains genuine tetraethyl lead and is heavily advertised in Hemmings Motor News and other sources.

The citations are from both the CFR and the Clean Air Act of 1990 itself. From Binational Toxics Strategy | Great Lakes | US EPA :

Section 211(n) of the 1990 CAA states: "After December 31, 1995, it shall be unlawful for any person to sell, offer for sale, supply, offer for supply, dispense, transport, or introduce into commerce, for use as fuel in any motor vehicle (as defined in Section 219(2)) any gasoline which contains lead or lead additives." This provision applies only to on-road vehicles. Enacting regulations were promulgated [61FR3837, February 2, 1996]....

...Thus, the sale or use of gasoline containing alkyl lead(greater than 0.05 grams of lead per gallon) is now prohibited in on-road vehicles [40CFR Part 80.22].

If you're using a lead additive in a street car, you can darn well bet that a caution "for offroad use only" is buried somewhere on the label, on the MSDS, or somewhere else in the material's literature. If not, you can darn well bet that the lead content of the additive is so small that it doesn't exceed the .05 g/gal. EPA standard when used per the instructions, which is WAY too small to have any real effect.

Besides which, the use of lead in today's gasoline isn't really a good idea. Not only are lead additives commonly known to clog carb jets during long term storage and even occasionally settle out in the tank, but their octane boosting properties are questionable at best and it's valve recession protection is nominal at best (and easily reproduced using any number of legal compounds). For a good discussion on fuels see this Pontiac Garage web page: https://home.comcast.net/~ericdouthitt/pump_gas.htm .

[Owen_Dyneto]

Dave, thanks for the citations, my original understanding was incorrect.

[Rusty_OToole]

marvel mystery oil

[TexRiv_63]

I am currently adding MMO and Stabil to regular pump gas, if there is no advantage to using premium would it help to add something like kerosene? If so I'd like to hear from folks who do that regularly to determine correct percentage.

[Rusty_OToole]

I am currently adding MMO and Stabil to regular pump gas, if there is no advantage to using premium would it help to add something like kerosene? If so I'd like to hear from folks who do that regularly to determine correct percentage.

It depends on what kind of car and what compression ratio. I got the idea from some English enthusiasts who add one part kerosene to 6 parts regular gas for their 20s and 30s cars and motorcycles. Then someone chimed in on this board, about using 1 part kerosene to 3 parts gas for thousands of miles, in a 1932 Buick.

The Buick had very low compression, 4.5 to 1.

If I had a car with 7 to 1 or higher I think I would use regular gas. Below that I might experiment starting with say 10% kerosene and see how it worked. If the engine started and ran well, and did not knock, I might try a little more and so on. If it knocked I would quickly add some fresh gas and next time, back off the kerosene.

[Guest 8Straight]

I'm liking this thread. Quite interesting!

My 52 Series 40 has a compression ratio around 6.6 to 1.

From what I have read so far, I think I should be reducing the octane a bit with kerosene.

I came across this article while browsing for the octane rating of kerosene. The difference beween Diesel Fuel and kerosene

It, and another article, say that kerosene is very close to diesel fuel.

This has me wondering, could diesel fuel be used to temper the octane in the gas?

Also wondering, would the kerosene or diesel have any upper cylinder lubricating properties? Would it raise the boiling point of E10 to help prevent vapour lock?

[Rusty_OToole]

Diesel fuel is heavier than kerosene which is heavier than gas. An old diesel mechanic advised that I could run my diesel car on kerosene in a pinch if I added a quart of motor oil per 10 gallons of fuel. He explained that kerosene is "too dry" and will cause excess wear of the injection pump.

Kerosene and diesel are oilier than gas and have a lubricating quality.

They used to talk about gas being a blend of light and heavy ends. The light ends for easy starting and the heavy ends for power. I take it the light ends were like naptha gas and the heavy ends closer to kerosene.

There is another angle on this. In the very early days of cars, namely before 1900, petroleum was refined for kerosene. Gasoline was a by product with little or no value, much of it was thrown away or dumped by the refineries.

This gas was so volatile, I have seen an account of a pre 1900 motorcycle owner who filled his tank one day in his garage but forgot to put the cap on the tank. The next day the tank was empty, all the gas had evaporated.

In those days they put as much gas as they dared in the kerosene and kerosene lamp explosions were a common hazard.

As gas cars became popular they sold more and more gas, as time went on they started putting kerosene in the gas to make it go farther. By 1913 it was common knowledge that the gas was not what it used to be, car makers lowered their compression ratios and started to add manifold heat to evaporate the new oily gas.

It was also about this time the long stroke engine came in possibly as a response to the lower quality gas.

Then the cracking process came in, making it possible to turn low grade fuel into high grade fuel.

As time went on better gas became available and after 1928 tetraethyl lead additives raised octane artificially.

So you had a period of high grade gas before 1900, followed by lower and lower quality gas, followed by a period of improvements, interrupted by WW2 when you were lucky to get any gas at all, then the 50s and 60s when lead and octane reached new heights. Followed by gas shortages, and low octane unleaded fuels.

Depending when a car or engine was built it could have been made to run on various qualities of fuels.

It is interesting to reflect, in Back to the Future when they could not get the DeLorean to run in the 1880s, in reality at that time they could have ordered all the gas they wanted from any hardware store and it would have been high octane unleaded. For about 10 cents a gallon.

[Rusty_OToole]

To answer your questions kerosene or diesel does have more lubricating quality than gas. Either will help prevent vapor lock.

At 6.6 to 1 your compression is not that low. I might try a 10% kerosene blend for the heck of it but you will probably do about as well on 87 octane regular.

If you try the kerosene or diesel let us know the results. It would be interesting if you could pull up to the diesel pump for a gallon or 2, then fill the tank at the gas pump. See if you can freak out the attendant lol.

[Restorer32]

When travelling in the Middle East many, many years ago we rented a VW Bug. I distinctlyly remember a sticker pasted near the gas cap advising that only 60 octane and above fuel be used.

[Rusty_OToole]

VW beetles in the fifties and early sixties had around a 6.5:1 compression

[TexRiv_63]

Thanks Rusty and all, it sounds like kerosene blending makes sense. But we still have not heard from anyone who actually does this on a regular basis, anyone else out there who has personal experience with this?

[Guest 8Straight]

That's the answer I was hoping to see. I will be trying the diesel at around 10%.

It will be a long while before I can report back with any results though.

[Rusty_OToole]

I would be more inclined to use kerosene or stove oil but to each his own. Will be interested in your results.

[Guest 8Straight]

Kerosene and stove oil likely have a more consistent volatility. Diesel fuel is blended to suit the seasons. I like the idea of pumping some diesel directly into the tank when filling instead of carrying a jug and spout though.

I'm also assuming that it's more economical than the little bottles of upper cylinder lube. You have to wonder what's in that stuff. Could it simply be a paraffin product or seed oil (as mentioned earlier) with big claims on the label?

[Rusty_OToole]

A fuel delivery man told me years ago that diesel fuel was 80% furnace oil and 20% stove oil in summer, 20% furnace oil and 80% stove oil in winter.

This is in southern Ontario near Oshawa, about the same climate as upstate New York and the Midwest.

[TexRiv_63]

Thanks T-head, I will also give blending a try. I am not sure of the compression ratios on my cars but I assume the 28 Pierce will be lower than the 32 Cadillac, I will do some research. I only have a 6 gallon temporary tank in the Pierce so the blending will simple! I am still getting the fuel system back together on the Cadillac but I will also report back with results.

[Rusty_OToole]

1932 Cadillac 5.30 to 5.38 depending on model. I can't find the specs for a 1928 model 81 Pierce but the 1930 straight eight had 5.07:1 so I should think the 81 would be the same or slightly lower.