Early v8 fuel

civilwarlife

civilwarlife

Member
Do I need fuel additive in my 38 2-door. The engine is original stock so no hardened valve seats. What brand is best? Thanks
Terry
 
corvette8n said:
I just use non-ethanol fuel in my stock ‘41. How many miles do you drive a week?
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If you use Non-Ethanol fuel in your old Ford, or other old car, be sure to get it at some larger, BUSY, service station. Only place we have in town is a little old fly by night former Pure station, pump around at the side. I got a BUNCH of trash in the gas there. Had to pull tank and flush it out. No fun at 90. My 2¢.
 
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I, and most others I know, just use whatever regular pump gas is available. Never heard of that being a problem to any of our engines. I think the need for lead additives, the fear of damage to non-hardened valve seats, would apply to high performance engines. For our little engines, the way we drive our old cars, I think the need for additives is a myth. Others may disagree. Myths die slowly.
 
There is one fuel additive that I do use. Nothing to do with the non-hardened valve seats. Has to do with the tendency of the flathead valve guides to cause a sticky-valve problem, especially if not driven regularly.
Marvel Mystery Oil is a lubricant or solvent of some kind that has proven beneficial in the flatheads. It immediately remedied a persistent sticky valve problem in my car. So now I am a born-again believer in MMM.
 
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Welcome to the Barn! Lots of good advise here, and varied opinions, but mostly spot on.
Stabil and mmo are two good choices.
Your “original stock engine” has likely been rebuilt at some point, if indeed it is original, which is not very likely, unless you have something less than 50,000 miles original. Valve seats were hardened in all but the Korean War period, and even those engines have mostly been rebuilt with hard seats since then.
 
We did lose a lot of Dodge 5.2L and 5.9L heads at the phone company that did not have hardened seats. The factory continued to manufacture engines without hardened inserts for years after lead was eliminated from the fuel in 1975. It was eliminated because the lead destroyed the catalytic convertors and the oxygen sensors. The first thing that would happen with those Dodges was the check engine light would come on for a specific cylinder misfire, but no misfire could be felt or seen on a scope. When no problem could be found we would pull the valve covers, pull the rocker arms and stick a straight edge across the valve stems. There would always be one stem sticking up an 1/8" to 1/4" higher than the others. The valve would recess way down into the heads until the head cracked. Amazingly they did not run bad. I don't remember if it was mainly the exhaust valves or not, it's been a while. Since usually only one valve seat on an engine did this it was probably more related to the surface heat treating of that particular valve seat. Even though they did not have hardened inserts the cast iron seats were heat treated, but only a few thousandths deep. We would send the heads out to Adams Metalizing in Lancaster, CA to be repaired. They did beautiful work, they welded up the heads and installed new seats. Before I saw that done I had doubts a cracked cast iron casting could be repaired good as new but they did it and with no sign of the repair. They lasted longer than they did from the factory, I never saw one of their repairs fail. The machine shop cautioned us about doing valve jobs on heads without inserts because the seat grinding, ground away the surface hardening. The old thought of freshening up the valve job because the heads are off for some reason might not be a good idea, unless you plan to install inserts.

I have flatheads out in the garage with supposedly factory hardened inserts, so they were way ahead of their time. Maybe someone will chime in on which years had them. I have a 1915 Mack truck with factory roller lifters, they were really ahead of their time.
 
As Brian noted, all flatheads up through the 59xx (end of 1948) series had hardened valve seats in both intake and exhaust. I just run normal premium in mine - though I'm sure regular would work just fine.
 
With the low compression, I would think regular would work just fine. Glad to know I don't have to mix in an additive. What a pain that would be. I plan to run ethanol free though. Bit expensive, especially lately.
Terry
 
I’ve always just put non ethanol in my 38 just because that ethanol gas goes bad so quick and gums up the carb quicker.
 
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