Ok lets talk Gasoline

[Rhodesia]

Now I know these models back in the day only used regular leaded fuel (MoGas) and today our Gasoline has changed in the last 65 years. what I'm saying is I have a 1970 superbee with a 440 and I had to have the rings changed in order to except the unleaded fuel, now has anyone had to do this with these M37's? so far I have not had any issues but does not the unleaded fuel hurt the valves and piston rings? or do I really need to have the engine overhauled to except the unleaded fuel?

 

[Two Stroke Madness]

Lead was only utililized in gasoline engines to protect the valve seats in the head or block, and was also used to increase the octane levels of the fuel for use in higher compression engines. The lead would provide a cushion to the impact that the valves had on the cast iron, and would also slow down the combustion process. When the leaded fuels went away the engine manufacturers started using hardened valve seats to compensate for this wear. If you're having any problems with your engine other than valve seats then your engine is in need of a rebuild, but not because of the change in fuel.

 

[Recovry4x4]

Ethanol is more of an enemy than lack of lead. Use REC90 (ethanol free) fuel and be happy.

 

[Jbulach]

X2 on the valve seats, never heard of needing to change rings.


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[Roller]

The 230 engine in your truck has hardened valve seat inserts, stock from Chrysler. No need to worry about lead free gas.

Frank

 

[TGP (IL)]

As Frank said it has the hard seats.
Run it. won't be a problem.

Agree with Recovery, Ethanol is the bigger problem.
I haven't had any problems with our E 10/E15.
I'm sure when it goes up it will be more of a problem.
Tom

 

[pjwest03]

Detonation will ruin the rings, not necessarily due to the lack of lead. The 440 probably needs higher octane.

The main problem with modern gas in old vehicles, other than valves is ethanol. Ethanol eats rubber gaskets, seals, o-rings, and hoses. You'll generally need to replace them with ethanol resistant versions. A water separator fuel filter is not a bad idea either as ethanol attracts water, particularly in vehicles that sit a lot. Also, I tend to go for the ethanol free premium that's available. Heck, my chainsaws and trimmers will barely even start with the E10 regular gas.

 

[eaw46]

Ethanol is very bad for our old stuff and so is the newer oils that lack Zinc and Phosphorus. Check it out on the net. You should use non ethanol premium and add a Zinc additive. Eddy

 

[Captaincarrier]

Ethanol is not good for the older O-rings, gaskets, seal, etc.

 

[JoeM35]

Does anyone use Aviation gas? I have used 100LL av gas that contains lead and no ethanol. Stores much longer than regular gas without going stale. My M37 starts easier and runs smoother. More expensive but no more than I drive my truck, it's worth the benefits.

 

[hndrsonj]

I run premium with no ethanol in all my "weird" stuff, whether it be the M37, lawn mowers, chain saws Etc.

 

[M543A2]

We have no ethanol fuel available through Co-Op stations here. It is also available at marinas. Paying the extreme price at airports for 100LL is not a good idea in my estimation. The no ethanol Co-Op runs currently about $3.14 per gallon. I saw at the airport last time I was there that 100LL was over $4.00 per gallon. I run the non alcohol in all of my older engines, saws, and other small engines. Ethanol fuel destroys older fuel pumps and rubber components of the fuel system. It also phase separates over time and rusts tanks and other steel parts in the fuel system. It will corrode aluminum or zinc cast carburetors. Not good at all for older vehicles and ones infrequently driven. It WILL cause you problems given time; not a matter of if. If you have to run alcohol fuel, hard seats in the exhaust valves is a must.
Never heard of rings having to be changed in a Mopar or any other for the reason stated. We have never had the problem. For oils, add STP or ZDDP to give zinc content in the oil for all flat tappet motors. If you do not do that with modern oils you will take out the cam and tappets, rounding cam lobes and cupping tappet bottoms. I curse EPA with every breath for the things they do that are actually destructive to us and the economy! I would like to see how much they cost every individual because of their regulations. They are a regulator without any over-watch organization to force them to prove the need for their actions before implementation. Good to see they are being handed walking papers in many ways now.

 

[Elwood1968]

I run premium with no ethanol in all my "weird" stuff, whether it be the M37, lawn mowers, chain saws Etc.

Do you use the premium because it's the only grade available without ethanol, or is there another reason for choosing a higher octane?

 

[pjwest03]

Do you use the premium because it's the only grade available without ethanol, or is there another reason for choosing a higher octane?

In most places it the only option available for ethanol free. Ethanol free below 91 octane is a rare item. A lot of small engines also seem to run far better on high octane as they don't have computers to compensate for the fuel conditions. All my Stihl 2 cycle stuff will barely run without it.

 

[TGP (IL)]

No choice here.
Everything has ethanol blend in all grades.
Tom

 

[Storm 51]

I use Amsoil products in everything on my M37/M42. It has the lead/zinc for the tappets and cam and the lighter viscosity in the gear cases makes everything run much smoother. Lubricants have improved significantly over the last 65 years and I try to take advantage of that.

I also use an additive to my gas to remove the ethanol and protect the carburetor, pump, and other parts of the fuel system.

Just my $0.02 worth.

 

[Jbulach]

....I also use an additive to my gas to remove the ethanol and protect the carburetor, pump, and other parts of the fuel system.

Just my $0.02 worth.

What is this magical additive you speak of?

 

[Storm 51]

Sta-Bil 360 Performance.

 

[GUNNY 155]

I have been running regular unleaded. Had my gas tank internally coated and rebuilt my fuel pump with parts to handle the ethanol When I rebuilt the engine all valves were replaced and hardened seats were installed on the intake and exhaust. I run Valvoline SAE 30 racing oil which contains zinc for flat tappet engines. Also use the Sta-Bil that Storm was talking about. So far no problems. In Illinois we have only ethanol fuels plus in Chicago we have a "special summer blend" which costs more and is only used in the summer because cars wont start in the winter when running it. So who know what that contains. So far no problems with mine.

 

[NAM VET]

Gunny, here in SC the gas stations in the "winter" or what passes for winter sell a gas that has a higher Reid Vapor Pressure, a fuel that vaporizes more, for older carburator cars. In my Superformance 427 Cobra Replica I had carb percolation troubles with the Winter fuel, and could tell immediately in the fall and spring when the Winter gas came and went. It can indeed make a difference in the starting and drivability of our M37 trucks.

NAM VET