1941 Oil and Gas

[First Buick]

Sooner or later, I will need gas in my newly acquired 1941 Special coupe (40-A), single carb, and I was wondering what gas these require.  My old '38 Chevy ran fine on regular gas but don't know if that is suitable for the Buick engine.  Are any additives needed?  The engine has been repainted but I do not know if it was rebuilt.  It has 81,xxx miles and other than the engine paint, it is pretty much all original,  and doesn't smoke or drip oil.  Also, what is the best oil to use?  I used to use a little Marvel Mystery Oil in the Chevy  but again, don't know if this is appropriate for the Buick.  I know there are lots of opinions on these issues but would like a consensus from you Buick folks as I am one of you now.  Thanks.

[Matt Harwood]

Use the cheapest low octane gas you can find. If you can avoid ethanol, do so, but it's not critical if you drive it regularly. It's only when it does a lot of sitting that ethanol starts to make mischief. The owner's manual specifies 72 octane for best performance, so the cheapest, low-octane swill found at the corner gas station will be just fine. High-octante premium might even make it run worse as the 6-volt electrical system sometimes can't make a hot enough spark to light off the high octane fuel.

 

I'm not a fan of additives of any kind. Lead is a non-issue and largely a myth, so don't bother with that. Zinc in the oil is another hotly debated topic but I don't think our Buicks have the kind of spring rates that demand excessive amounts, so maybe just find an oil with some extra zinc in it if you're truly concerned. Any oil from today will be vastly superior to oils of 1941, so whatever your preferred brand is will be fine. If you like MMO, it can't hurt, but it's just transmission fluid or hydraulic oil so it doesn't do anything truly "marvelous" or "mysterious." Stick to a routine that makes you feel confident, which is the most important part. These cars no longer get driven hard enough or distant enough for typical "wearing out" to be an issue so even with modest maintenance it should last indefinitely. Just enjoy!

[Mark Shaw]

     I believe that just about any oil today is better than what was available in the early 40s.  If your car has an oil filter, you can use just about any multi-viscosity oil with additives to keep your engine clean and well lubricated.  However, if you do not have an oil filter, and your engine has not been rebuilt, I suggest you use what is commonly called "non-detergent" oil. 

     Most older engines were designed with large oil pans to act as settling basins to slow the flow so solids could settle out.  The additives ("detergents") in modern oils are designed to suspend solids and other contaminants so they can be filtered out of the system.  If your engine has not been rebuilt, these new oils will suspend "abrasive contaminants" that will be circulated in your engine. 

     I also suggest that you avoid gasolines with ethanol.  Since most older cars are not driven every day, you will avoid the problem of ethanol phase separation within a relatively short time.  Old cars just run better on non-ethanol gas and you will avoid deterioration of natural rubber and/or aluminum components that ethanol will destroy.  

 

What is phase separation of ethanol?

Ethanol-blended fuels left untreated can start “phasing.” Phase separation is when ethanol in the fuel absorbs too much water, and separates from gasoline by dropping to the bottom of the tank since the ethanol and water mixture that results from phase separation is heavier than gasoline.

[Ben Bruce aka First Born]

Well said Matt.

 Welcome to becoming " one of us", First Buick.  Get ready for a treat after the Chevy.

 

  Ben

[First Buick]

Thanks guys.  You have set my mind at ease.   Lowest octane, ethanol free gasoline, and, since I have an oil filter, a good multi viscosity oil appropriate for the season are what I will use.