Fuel choices for M 38

bucky · Post by **bucky** » Thu Jun 14, 2007 8:38 am

Well, I have been told now by several people, that jeeps would burn just about anything Except diesel because it ran to hot. One guy even suggested used cooking oil! Has anyone tried a diffrent fuel than gas and how did it work? Thanks Bucky

bfr · Post by **bfr** » Thu Jun 14, 2007 12:42 pm

fuel choices I would run in a m38...
1. gasoline
2. see #1

Post by **wesk** » Thu Jun 14, 2007 7:17 pm

73 to 89 octane auto gas is the best fuel choices. Yes it will turn on alcohols, ethanol and panther piss but these will have ill long term effects on the engine. They are considered emergency fuels only. Diesel will really piss you off when it quits and you have to clean up the mess.

dv3468 · Post by **dv3468** » Thu Jun 14, 2007 7:23 pm

Now that you mentioned it. I have been using unleaded regular (87 octane) in my M-38 and it runs fine. Would it run better with high test (91 octane)? What about these lead substitute additives? Weren't the L134 Go Devil engines designed for leaded gas?

bucky · Post by **bucky** » Thu Jun 14, 2007 11:38 pm

Thanks guys, I really wondered about that. Much cheaper to ask than try it. Bucky

Post by **wesk** » Fri Jun 15, 2007 7:19 am

Yes they were designed during a period when virtually all available auto gas was leaded. They were not dependant on the lead. The lead was there to raise the octane. A side benny was a little valve lube. This higher octane was meant for the higher compression higher RPM turning performance engines. The jeep engine was designed to run on any of the lower octane auto gases since it was turned a lot slower and had lower compression ratios.

So what happens when you run modern unleaded gas? Nothing if you drive the jeep the same way it was designed to be driven. If you do all highway driving and operate above 3000 RPM most of the time then over time you will risk an occasional burned valve or seat from the higher burning temps of the unleaded gas. The answer to this minor issue is the hardened valve seats and stelite exhaust valves Kaiser introduced 50 years ago.

dv3468 · Post by **dv3468** » Fri Jun 15, 2007 12:16 pm

Thanks for the info Wes. As usual, you are the man in the know!!

Regards, Dennis