Willys F Motor Oil?

[Brad]

If this is the wromg location to post this I apologize, but I am stumped. I have found very helpful info on here relating to my Son's 1952 M135, and hope I can get some help again?
I just purchased a 1953 Willys CJ3B with the OHV engine.
In my other old flat head and the M135 we were using Rotella T. I believe it was due to neading lead content?
Anyway the man I bought this from has Castrol Magnatec Full Synthetic 0 W 20 in it. Can that be OK? He says he had just changed the oli and it dont have 25 miles on it. Beore that he had 10 W 30 HD of different types in it.
Don't I need oil with zinc in it? What would be best and is synthetic OK?
I am reluctant to even start it up until I know.
Thanks in advance

 

[dependable]

I has several Willys jeeps when I was younger, always used 10W-40 in them. 10W-30 would work fine too. 0W-20 is too light (low viscosity) for any older engine, though I doubt any damage was done in 25 miles. The 0W-XX oils are for modern engines with very tight clearness.

These are tough, simple engines, if you want to add a zinc additive, it probably would not hurt, I would not bother.

You have an F head engine with overhead exhaust valves, which is the same as L head engine, aka flathead, except for head.

 

[dmetalmiki]

Everything I own..(See avatar and list)
Runs on, Has always run on, Will continue to run on,
Rotella straight 50. That's it.
I have a 50 gallon drum of rotella straight 40 I will use when the 50 runs out.
Every truck I own has MOLYSLIP added to EVERYTHING.
Engines axles gear boxes tranfer cases steering boxes, And Everything is greased up with Molyslip grease.
My jeep of many many years has run NO oil in the gearbox, transfer case, wheel hubs or steering box.
They have always been packed with molyslip black grease.
Someone at a military event once told me.. "Huh" That won't last a month!!


IN.....................19.........................50.................8 !!

 

[Brad]

Still has the synthetic blend in it. I do not like that but have seen other places that a lot are using synthetic??
Runs good, sounds good. But does have a tappet sound happening. Also once wormed up, has very low oil pressure especially at idle. Just about ZERO.
Wonder if using the Rotella 4 would remmedy this? Once I change I don't think I could go back if it didn't help?
I know what my dear old Dad would have said. Get rid of that synthetic and go to standard 30 weight non detergent. But that has no zinc.
Advice please???

 

[Mullaney]

Still has the synthetic blend in it. I do not like that but have seen other places that a lot are using synthetic??
Runs good, sounds good. But does have a tappet sound happening. Also once wormed up, has very low oil pressure especially at idle. Just about ZERO.
Wonder if using the Rotella 4 would remmedy this? Once I change I don't think I could go back if it didn't help?
I know what my dear old Dad would have said. Get rid of that synthetic and go to standard 30 weight non detergent. But that has no zinc.
Advice please???

.
Or straight weight 40. You can add the zinc if you feel the need.

 

[marchplumber]

What's wrong with Rotella 15-40? decent oil, wont cost ya an arm and a leg. Or Valvoline 10-40?

I agree with prior post, old engines don't get synthetic oil.

 

[Brad]

So I changed the oil to Rotella T 15 W 40. At first seemed to have higher oil pressure. But after a good run it is about the same. At idle it is near zero? Could this be normal for these engines? I have heard some so it is?
I sure don't like it. But it runs fine and seems to be ok, but might I be doing damage?
How much work to rebuild the oil pump, if that is even a remedy???
Thanks

 

[flatheadvff]

So I changed the oil to Rotella T 15 W 40. At first seemed to have higher oil pressure. But after a good run it is about the same. At idle it is near zero? Could this be normal for these engines? I have heard some so it is?
I sure don't like it. But it runs fine and seems to be ok, but might I be doing damage?
How much work to rebuild the oil pump, if that is even a remedy???
Thanks

As an engine builder and mechanic, with decades of experience, I'll say the oil pump is rarely the cause of low oil pressure. Not never but rarely. (What's the first thing to get oil, so what would rationaly be the last to wear out). Most often by a large margin bearing clearance is the culprit. Main bearing and cam bearing. Rod bearings have little effect on oil pressure. If memory serves me oil pressure spec on these motors are very low. 3-5 psi at idle. Rotella 30w was the engine break in oil for a time, it was one of the last with zinc in it, it no longer has zinc. Zinc is critical during break in, especially for cam and lifters. (Highest friction point of engine, why roller valve train is one of easiest ways to find extra horse power.) So once motor is broken in it isn't necessary, why they can remove it from oil. Have zinc rich assembly lubes now critical for bulding engines. Again if memory serves, these were easy to remove pan in vehicle and slide new main and rod into. Cam bearings would require almost complete disassembly. I believe I still have a manual on these, I'll check on specs and send another reply. (May take awhile, in the middle of trying to get fall crop sown.