Oil Recommendation for a 1966 Ford F100

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Are you sure about that mileage?
A fifty yr old engine usually would have much more
Was it in a barn for the last 40 years?
Have fun with it,they are very easy to work on
 
Originally Posted By: bigt61
Originally Posted By: zray
Mobil 1 15w-50.

I use it in all of my vintage cars, and it is the oil of choise for any vintage car I work on.

Z

Yeah, your vintage cars are clean & pampered - I'm sure the M1 works great. In this old "possible sludge monster" truck, maybe not so much. The fresh oil might have dislodged enough junk to partially block the pick up screen reducing oil pressure. I'd drive it gentle & easy for a short OCI and see what drains out - chunks are bad. 10W-40 SuperTech is likely all you need in the future.


I wish every vintage car I've owned or do own had been pampered by me from the beginning, life would be so much simpler then. When I get them, they are in every conceivable condition, from pristine looking, to ragged & running oil that looks like molasses and smells like great grandads outhouse. I put the M1 in them all. The worse an engine has been treated, the more it needs the benefits of a quality synthetic oil.

Just my 2 cents.

Z
 
Originally Posted By: Dallas69
Are you sure about that mileage?
A fifty yr old engine usually would have much more
Was it in a barn for the last 40 years?
Have fun with it,they are very easy to work on


I'm pretty sure, the truck is in immaculate shape, it was very well cared for. I don't think I'll run into much trouble working on it.
 
Quaker State Defy in 10W40 has a really good add pack and seal conditioners, which your engine will definitely need. 15W40 has a good add pack too but lacks the seal conditioners. I would run QS Defy 10W40 in your engine.

If the oil pressure continues a downward trend, 20W50 will work fine in this engine and may be just the ticket to keep it running for a while.
 
20w50 is not going to raise it 30psi. As mentioned, I would remove the sending unit (under the rear cylinder, behind the filter) and screw in a different oil pressure gauge to verify.

Those sending units do like to plug up, and they used the same one on numerous engines. A couple years ago I bought a 72 with a 240. When I took a couple mile test drive, it carried good. Then after I changed it, I didn't make it more than 20 miles and it was losing pressure. Bottom of the screen was plugged up with sludge.

Verify the pressure
 
If you are worried just change out the sending unit
They are cheap and easy to do
Then you can go from there
 
Both my Dad and Grandmother had the truck, same year and engine. Thats the truck I first learned to drive & as a manual.

What they used: Summer was always straight 30 wt, and Winter was 10w30. She also had about 120,000 miles on it. Great engine. They seemed to prefer using Fram filters, too.


The suggestions of changing to a 15w40 are probably spot on...especially if there is a high mileage flavor.


GL
 
Great suggestions guys, I'm going to check the pressure with a mechanical gauge, and hope its the sending unit, I'll let You guys know what happens.
 
Great news guys, I replaced the sending unit, and all is well! I have around 35 psi fully warmed up, which seems pretty good all things considered, Not sure what it is cold yet, I would assume more. But anyway, thanks for all the help guys!
 
Originally Posted By: Death_Eagle_571
Hey guys, I'm new here, and I just bought a 1966 Ford F100 with the 240ci Straight-6 engine, I'm not sure what oil was in it when I bought it, but it was pretty nasty looking. The oil pressure at 2000-2500RPM was around 55 psi. since then I changed the oil and used Shell Rotella-T 15W-40, it has dropped to around 20-25 psi. the Specification for my engine is 35-55 psi @ 2000RPM I was reading that my truck called for Straight 30W oil, but I was under the assumption 15W-40 would work, and the ZDDP additives in this were sufficient to protect the flat tappets in my engine if I understand it right. Anyway, any ideas guys?
What is the psi at 3,500 RPM?
 
Originally Posted By: HM12460
How about some picture's of this golden oldie??


Here ya go, its a beauty!

A-trip-back-in-time-I-524603569


A-trip-back-in-time-III-524603602


A-trip-back-in-time-VI-524603642


A-trip-back-in-time-VIII-524603668


[/quote]What is the psi at 3,500 RPM? [/quote] Not sure actually, I'll check and see, I would venture a guess it would be around 50 psi.
 
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You got it right with Rotella 15W40... Great oil in your application. I'm thinking that you may have had a 50 weight oil in the last OCI. What is the oil pressure at idle? Old school is around 10 psi min per 1000 rpm.
 
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Originally Posted By: Death_Eagle_571
Who knows what was in that thing lol, its around 20 psi idle, 35 at 2000-2500 RPM.


Sounds like it is within spec. Enjoy.
 
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