WWII Willys Jeep winter oil recommendations

[Gary Allan]

My neighbor has the same engine in his CJ. I'm unsure how the frame/cross members work on the OP's friends jeep, but this looks like a piece of cake to pull the pan. The side cover looks like it would require the exhaust manifold to be removed.

The only point being made is that it would appear little work (compared to the work already performed on the maintenance or restoration) would be required to clean this up if it had substantial deposits. After that, there's no reason not to take advantages of oils other than ND's.

I'd still be using a 20w-20 in this thing in colder weather.

 

[zrxkawboy]

I can't imagine the cost of changing Mobil 1 as often as it would get dirty in this engine. Plus, as mentioned, it would be overkill. I would use the cheapest modern 5W30, 10W30, or 10W40 I could find (you could even mix 5W30 and 10W40), and change it often. It will flow much better on cold days than the 30 it's had prior.

 

[rclint]

My knowledge base on non detergent, non filtered engines is air cooled engine based, and many here would be fooled by how clean they are. Like I said I have a Kohler, and have seen other Kohler tear downs, the bottom end was spotless, however the pan did have a balck color to it, not sludge, nor dirt mind you, however it was just like a coating of black oil, maybe that is the reason for non detergent oil, maybe that was the dirt etc in the oil, and it coated the pan, or dropped out, and was in the layer of oil coating the pan. Whatever the case, all rotating part were spotless clean, and no undue wear, even so as to the crank, and connecting rod, all were within spec, the only worn part was the piston, and I'm not sure if the cause of this is single cylinder design, or maybe bad filtering ? Non detergent motor oil does not mean his motor is sludged up, or dirty, however just because of the mere availability, and service history of HDEO oils like Delo, and Rotella SAE 30 is the reason I suggested these oils, I also run them myself, and have run them on farm equipment for years without any starting problems in freezing weather (diesels even), and will agree with above poster that most starting issues are either fuel, or ignition, I doubt it has anything to do with the oil. Also keep in mind the HDEO will or should keep any cleaning done suspended in the oil. SAE 30 is a very robust oil, and made for engines like this, you can almost look at the Jeep as a piece of farm equipment.

 

[addyguy]

I would not continue with non-detergent oil in this engine! You just have to get it 'switched over' to run detergent oil. It will be better for it in the long run!

The first thing you have to do is determine how clean the engine is inside. If it is perfectly clean, you can just switch over to a regular oil, do a couple of changes, and be good to go.

However, if the motor is severely sludged, you will have to clean it out - either by disassembly, or by slow 'liquid cleaning' with detergent oil.

Continuing to run detergent oil in a dirty engine may keep it going in the short run, but eventually it will 'catch up' to the engine, and it will seize. Engines run before the era of detergent oils eother got cleaned out regularly, or they got periodic tear-down to do the same thing.

Please don't wreck ths nice, rare classic with out-of-date thinking!

 

[Trvlr500]

Originally Posted By: Drew99GT
I wouldn't do the Rislone as it's intended purpose is to clean.


That is the reason I recommended the Rislone at half the dose they recommend. Rislone cleans slowly over a few thousand miles or a couple of oil change intervals even with a full dose so you don't get a real harsh cleaning that could possibly plug up and oil gallery. Using a half dose with some non-detergent 20 weight due to the weather where the OP lives would work fine IMO. Once he knows its clean inside (unless he takes it apart) he could run a modern high detergent oil of the proper viscosity. Just my .02 cents. Rislone is also a 20 weight.

 

[artificialist]

Recently at Bumper-To-Bumper auto parts, I did see non-detergent multi-viscosity engine oils.

They were available in 10w30 and 20w50, and the label said API SA, not approved for vehicles built after 1950.

However, they were on the clearance rack, so I don't know if any is left in your area.