VCCA Home Forums GENERAL DISCUSSION General Discussions Unleaded gas

Hello everyone, I'm sure this question has been asked before but I don't know how to find an old thread, so here goes. Will unleaded gas hurt the valves in my 35? I heard stories both ways. Some say it ruins the seals and guides, others say that there is no problem. Some say the gas is fine just stay away from ethanol. In Mass there is 10% ethanol in all the gas. Do I need lead additive? I'm sure it wouldn't hurt but why spend the money if I don't need to. TIA, Pete V

Lowest octane regular gasoline is okay. I pay extra for gasoline that does not contain ethanol. It can often been found at marinas and airports if not at gas stations. Occasionally put a glug or two of universal automatic transmission fluid or Marvel Mystery Oil in the gas tank. The lubricant will help reduce sticking of intake valves. Modern gas oxidizes fairly quickly so try to keep fresh gas in the tank. On some of my cars I drain the gas tank, carburetor, vacuum tank if I expect to have it inoperable for more than a few months.

Hardened valve seats, octane boosters, "lead" additives are a waste of money.

From what I've heard, you do not need leaded gas or a lead additive unless you're going to be racing the car. The previous owner's of my '41 with a 216 straight six used a lead additive but I don't and it runs just fine.

As long as you rebuild the carb and fuel pump with modern parts that can handle ethanol there shouldn't be a problem there, either.

I run straight 87 octane in mine. I know the carb can handle ethanol but I'm not sure about the fuel pump since that's still original.

Down here non-ethanol is $2.99 per gallon. 87 octane with <10% ethanol is $2.28 per gallon. Guess what I use in everything except the one car calling for high-test.

87 octane with <10% ethanol is just fine for the old 35. As Chipper indicated, it may not be as stable after months of storage smd may then, some believe. damage some non-ethanol resistant minor cheaply made parts.

Avoid all the smoke and mirror fantacies regarding claims against ethanol. People who go around attributing all vehicular woes to ethanol remind one of Chicken Little going arround yelling "the sky is falling." It just ain't so.

Best,

Charlie

Thanks everyone. Looks like I don't have to worry about the unleaded gas. Good news.

Regular unleaded is just fine and you don't need hardened valve seats. Lead in fuel wasn't common when this engine was new.

Unleaded with 10% ethanol is fine for a regularly driven vehicle where the gas is used/ replaced within a month or so. It reduces horsepower by about 15% compared to regular unleaded without ethanol but the price offsets this.

Try to avoid ethanol in small engines or any application where the fuel will sit more than a month or is exposed to high humidity like a boat as the ethanol forms a nice jelly-like substance when it gets water in the fuel.

I agree almost 100 percent of the above except I have never experianced a power loss with 10% ethanol.

And yes in 1935 the only gas that had lead was the higher octane Ethyl grade. Lead was added to raise the octane which meant the gas burned slower to eleminate pinging in high compression engines....which Chevrolets were not.

This is a good neutral article on Hemmings.

https://www.hemmings.com/blog/2012/...oline-and-its-effects-on-collector-cars/

The only fuel available until well after 35 was unleaded and about 75 octane.
As for E10 make sure all rubber parts are suitable and expect a power and economy drop. I have a 92 Subaru that is slightly cheaper (50 cents/ tank full) on 94 non ethanol than on 91 E10 with similar driving conditions.
Tony

Charlie - you are absolutely correct! I have had a couple of flat tires, that I am sure were NOT caused by the use of ethanol!

However, I would suggest avoiding the stuff if you can, it is hard on fuel pump valves, as well as some carburetor parts; and it definately will cause both lower fuel economy and less power (unless you are running about 13:1 compression, and about 20 degrees BTDC static timing).

OP - as others have mentioned, the lead additive is NOT needed on your engine, and some of the various ones can foul spark plugs.

Jon.