Engine oil for vintage Willys Jeep

[RogerCJ3B]

Hi,

Thanks for adding me to this group J

I just have assembled my engine after major overhaul, including boring of cylinders and have to decide what engine oil I am going to run.

It is a 1953 Willys Overland Jeep CJ3B with an F134 engine. 4 side valves and 4 overhead valves, with flat tappets. It will be used now and then, but the temperature alternations here in Norway are considerable -20℃ to 30℃. Will not be used as my everyday vehicle.


Specification from service manual 1965:

Not lower than 32 F. (0 C.) use SAE 30 or 10W-30

Not lower than 10 F.~ 12 C) use SAE 20, 20W. lOW-30, or lOW-20

As low as 10 F. (-23 C.) use SAE l0W, l0W-30, or 10W-20

Below 10 F. ( -23 C.) use SAE 5W or 5W-20

From this it seems like 10W-30 is the obvious choice, but isn’t it better to use SAE 10W-40 or even SAE 5W-40 to benefit from the newer technology that gives better viscosity index?

This is an engine with flat tappets and what I have learned long time ago is that high level of ZDDP additives like Zink is necessary on engines of this type, is that still true or is the ZDDP additives replaced by something else in modern engine oils?

The high level ZDDP oil I have used in the past is now replaced with Fuchs TITAN UNIVERSAL HD SAE 15W-40.

What experience do people in here have with engine oil for vintage cars?

 

[jeepman3071]

A friend of mine uses a Willys CJ2A on his Christmas tree farm. I believe it has that same engine. He usually runs a 15w40 in it (Rotella or Supertech) but used the semi-synthetic 10w30 Rotella T5 the winter he plowed snow with it, since it was a bit easier to start with the 6 volt starter in an unheated barn. I wouldn't worry too much about the benefits of one oil over another, either one will be way better than they had back in the 1950s. The oil being able to pump up to the top end quickly in cold temps is most important.

 

[wpod]

Todays oils are much better than those of yesteryear. Those engines are very low pressure / output.

 

[RogerCJ3B]

A friend of mine uses a Willys CJ2A on his Christmas tree farm. I believe it has that same engine. He usually runs a 15w40 in it (Rotella or Supertech) but used the semi-synthetic 10w30 Rotella T5 the winter he plowed snow with it, since it was a bit easier to start with the 6 volt starter in an unheated barn. I wouldn't worry too much about the benefits of one oil over another, either one will be way better than they had back in the 1950s. The oil being able to pump up to the top end quickly in cold temps is most important.

Thanks, on other engines I have been running Fuchs TITAN UNIVERSAL HD SAE 15W-40, a mineral oil, with no issues. But I am tempted to go for a semi-synthetic oil like 5W40 for quicker lubrication on the top end
It is almost the same engine, but CJ2A has side valves only.

 

[wpod]

Thanks, on other engines I have been running Fuchs TITAN UNIVERSAL HD SAE 15W-40, a mineral oil, with no issues. But I am tempted to go for a semi-synthetic oil like 5W40 for quicker lubrication on the top end
It is almost the same engine, but CJ2A has side valves only.

I would say the 15W-40 is a better lube, but I run 5W-40 [syn] in my tractor for starting below freezing .

 

[Fitter30]

Use something like this with a high zinc content

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[k1xv]

With the oils available today, and assuming the seals are updated to modern materials, I think a manual written today would list 5w-30.

 

[wings&wheels]

Being as you are in Europe, I would consider this or something similar; Millers Classic Oils

 

[demarpaint]

I'd use either Mobil 1 0W40 or 5W40 in it. That would cover just about any climate.

 

[nwjones18]

I'd think an HDEO in either 10w-30 or 15w-40 would either work.

 

[Creekside]

I have a Willys F head in a Airco welder, I believe it is the same model as yours. I run a basic 15w40 in it year around. It has an old school Fram bypass filter that uses the Wix 51010 cartridge. It will sometimes run for hours on the governor. I usually change it in the spring every couple years.

 

[Don_B]

Reviving a few month old thread.
Located anywhere near Chicago?
Want some of what the factory recommended back then? Even comes in old school cans, not current day plastic bottles. I have about 60 cases of old school 20w20, 48 cases of which are quaker state. 12 cases or so of Pennzoil and citgo. The Pennzoil is 24 cans to a case even. Listed in BITOG for sale section.

 

[Bill7]

I prefer to think of viscosities in terms of HTHS. A HTHS >= 3.5 meaning a euro 10W-30 or any 10W-40 would be a good choice.
Since 5W oils didn't exist then, it might be better to use a good 10W-30 Synthetic. You might want to add a ZDDP/Phosphorus additive for additional wear protection as the newer oils have limits on those.

The owners manual doesn't mention 40 weight oil.
But if you wanted to use a 40 weight, should be fine just in case the engine clearances have increased over the years.