Oil for a 1965 F100 Inline 6 with flat tappets and hydraulic lifters....

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Well, I've been a bad boy and haven't paid much attention to state of the art, but I do know that they continue to change the oil formulation and what is good for my 2020 RAV4 would probably cause my 65 to throw a rod in 20 miles. I've not changed the oil in the 65 for several years (it gets very few miles), but its time.

I'm sure its been discussed, but I could not find it with search. Should I:

-- run a diesel engine oil?

-- buy conventional high mileage oil and add some ZDDP additive?

-- spend piles of money on Lucas or Amsoil oils specifically marketed for really old engines?

The engine leaks a little oil from the pan gasket and a little from the rear mail I think. By little, I mean 10 drops over the winter. But I would not want to try a synthetic or probably even a semisynthetic, unless one of you can argue very persuasively.

Thanks in advance, from a long time lurker.....
 
I'd stay far away from Lucas oil. you don't have a high output engine with stiff valve springs. I bet SuperTech 5W30 will cause less wear than anything that engine saw years before I was born.
 
Originally Posted by CT8
Just run HDEO oil with the best viscosity for your starting temps.


Good recommendation. Rotella 10W30 would work well and not cause you to worry.
 
Originally Posted by cdherman
Well, I've been a bad boy and haven't paid much attention to state of the art, but I do know that they continue to change the oil formulation and what is good for my 2020 RAV4 would probably cause my 65 to throw a rod in 20 miles. I've not changed the oil in the 65 for several years (it gets very few miles), but its time.

I'm sure its been discussed, but I could not find it with search. Should I:


The old Ford i6's had very light valve springs and could run on any oil under the sun. These engines are NOT hard on oil and do not have extraordinary AW requirements.

Originally Posted by cdherman
-- run a diesel engine oil?

If you can get it cheap? Sure! It's certainly not going to hurt.

Originally Posted by cdherman
-- buy conventional high mileage oil and add some ZDDP additive?

Definitely not necessary, you do NOT need added ZDDP, an HM oil would be fine by itself and might help with your leak.

Originally Posted by cdherman
-- spend piles of money on Lucas or Amsoil oils specifically marketed for really old engines?

Avoid Lucas like the plague. It's like mixing dog faeces in with your steak sauce.

While AMSOIL makes some excellent lubricants, I doubt you are going to see a benefit from them in this application.

Originally Posted by cdherman
The engine leaks a little oil from the pan gasket and a little from the rear mail I think. By little, I mean 10 drops over the winter. But I would not want to try a synthetic or probably even a semisynthetic, unless one of you can argue very persuasively.

Thanks in advance, from a long time lurker.....


Then the HM oil (by itself, not defiled with additives) would likely be your best bet.
 
OK, well back to HDEO then. I was running Rotella oil from 2002 till 2016 which is probably the last time it was changed. Planning to generally swap/replace fluids given all the time I have on y hands.

Thanks for the replies.
 
SuperTech. It's what my 300cu likes (but the synthetic version). A HM oil would be my choice for your engine (because of the oil seeps).
 
T5 is my goto oil for anything that is flat tappet and stock spring.
It's good oil, don't ruin it with any snake oil additives.
 
Originally Posted by CT8
Just run HDEO oil with the best viscosity for your starting temps.


^^This … Delo, Delvac, and so on …
 
Originally Posted by Jackson_Slugger
I'd just use a quality high mileage 10W-30, I'd be more worried about seals than any "wear"...

Ditto. Run a HM 10W30 or 10W40, depending on oil pressure.
 
Originally Posted by Jackson_Slugger
I'd just use a quality high mileage 10W-30, I'd be more worried about seals than any "wear"...


OK, so this little project took longer than expected, so I am going to resurrect this thread with my next question:

What about a HDEO with say 5w-30? I do start the old girl in the winter sometimes? I have good oil pressure, even hot, and no rattles or lifters knocking, so I don't think a 40 weight oil is needed.

What about a High Mileage synthetic oil? Like the extended performance Mobile one 5w30 High Mileage? I have some very mild leaks, but the HM formula might help that? Perhaps more than a HDEO like Rotella would? I happen to keep a supply of that oil for my old subaru, and I'm trying to simplify the shelves.....

BTW, $$ is immaterial, but I hate buying stuff online, as its so hard to change your mind......
 
I owned a 1978 F100 with a 300cid 3speed on the column
Only used QS 10w-40 for 250,000 miles
Sold it and it survived for many more years

Ford inline motors will run along time with a decent oil and changes
You pick and it will be fine !
 
My 270 Jimmy inline 6 with flat tappets gets Castrol HM 10w30 in winter and Rotella or Traveller 15w40 in summer.

A good quality diesel oil works great in old inline 6 motors.

NewEngine-2006-1.jpg
 
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