:) Soon instead of reading ,Driving our Plymouth's will be upon us... Since it either snows or rain here in Pa... I hit the books.... In a 1953 Motor book, there is a article on type of gas and its recommendations and adjustments using different octanes of gas... The article seems to recommend higher octanes ... I have been using regular gas , has any body experimented with higher octane , Thanks for letting me know ... Happy Ply-mouthing DANiel
Unless you have modified you engine significantly then regular gas is all you need or want. Our current standard (in most of the US) of 87 octane would count as "high octane" fuel in the early 1950s. Regular back then was probably in the 70s.
Also, your L-Head 6 engine came from the factory with hardened exhaust valve seats so you don't need any lead additives either.
The only problem with modern gas is that some of the additives in it are not kind to old rubber formulations. Your fuel pump diaphragm, the rubber flex hose from the frame to the pump and, possibly, the carburetor float valve needle may be damaged by new gas. I'd just drive it and keep an eye on those components and be ready to rebuild/replace them with parts that are compatible with new gas.
So just go out and buy the cheapest gas you can find and have fun driving it.
I agree whole hardly with everything that Tod said about modern unleaded 87 octane fuel being just fine with no additives for the older cars, with the exception of waiting for the old rubber parts to fail.
The number of vehicles that catch fire as a result of fuel leaks from failed fuel lines, leaking fuel pumps etc., is staggering. I would advise anyone that has not done so, to do them selfs and their insurance company a favor by replacing the hoses and fuel pump with component's that are made for unleaded fuels.
A word of caution... If you purchase a new fuel pump, don't fool yourself into buying a NOS unit, make sure the pump is made for unleaded fuel. I purchased a new AC pump for a '53 Pontiac I have, AC being original equipment for a Pontiac. Within two months fuel was poring out of the pump, both externally and into the crankcase via the secondary vacuum pump. I sent the pump out and had it rebuilt using modern parts that would hold up to the unleaded fuel....Bill
Quote from: Wm Steed on March 05, 2008, 12:11:29 PM
I agree whole hardly with everything that Tod said about modern unleaded 87 octane fuel being just fine with no additives for the older cars, with the exception of waiting for the old rubber parts to fail.
The number of vehicles that catch fire as a result of fuel leaks from failed fuel lines, leaking fuel pumps etc., is staggering. I would advise anyone that has not done so, to do them selfs and their insurance company a favor by replacing the hoses and fuel pump with component's that are made for unleaded fuels.
A word of caution... If you purchase a new fuel pump, don't fool yourself into buying a NOS unit, make sure the pump is made for unleaded fuel. I purchased a new AC pump for a '53 Pontiac I have, AC being original equipment for a Pontiac. Within two months fuel was poring out of the pump, both externally and into the crankcase via the secondary vacuum pump. I sent the pump out and had it rebuilt using modern parts that would hold up to the unleaded fuel....Bill
I agree with Bill.? I had problems with the float valve in a NOS carburetor, which I installed in my 48 Plymouth.? ?With the L-Head 6 engine the carburetor sits above a hot exhaust manifold.? If the float valve fails the gas may pour out of the carburetor and all over the exhaust manifold.? The carburetor I am using is a Stromberg and my assumption was that the gas would flow out of the overfill tube and into the carburetor.? Not completely so.? With a strong pump a good portion of gas flows onto the manifold.? Very scary, especially with the engine racing from the additional gasoline and the gas steam bellowing off the exhaust manifold.? ?Keep a good fire extinguisher handy, better safe then sorry.
Just my 2 cents,? Chet?
PS, No air cleaner assembly installed at the time which might attributed to the potential fire hazard..
My 50 Plymouth has compression slightly in excess of 8.5 to 1. It runs just fine on regular unleaded with a slight ping if you get on the throttle too hard on a hill without kicking it out of overdrive. No valve problems in 40 000 miles except for occasional sticking after the car has sat for a couple of months. A quart of diesel in a ten gallon fillup seems to help this problem. If your car still has its stock compression ratio of about 7 to 1, it should run just fine too.