Hey guys,

Just picked up a F250 with a carb'd 460. The truck has been run with 20w50 by the previous owner. My limited research shows that a majority run 10w30, but these have been fuel injected motors.

Would a heavier 20w50 be better at protecting the motor or would a 10w30 be better as the pump won't have to work as hard to flow the thicker oil?

What is the general conscious on the best oil weight for our dear carb'd 460s??

 

it takes longer for heavy oil to get to every thing when ya start it up, i dont run nuttin heavyer then 10w-40

 

What does the manuel say to use?

 

20W50 used to be an oil good for the old loose tolerance engines, or engines running in extreme heat or old worn out engines needing a bandaid to keep them running.

I would do a compression check to see how the rings are and also do a visual check(lay out some cardboard after you stop the engine anc check in the morning) for oil leaks. If compression is good and you don't have any major leaks, I would go with a thinner oil. If you have the manual use what it says. Or post the year of your engine and maybe the miles.

If you live anywhere that it snows, you probably don't want 20W50. a good 10W30 or maybe 40 or a 5W30 would probably fit the bill. All depends on condition of the engine and when it was built.

I have used synthetic 5W30 or 10W30 in all my engines since 1980 and thru below freezing to well into the 120's. Last time I used 20W50 was in a Datsun truck with a 4 banger. I used Racing oil no less. I didn't know any better.

Good Luck,

Jim Henderson

 

Yea that is what I am beginning to think now that I read most people run a lower weight oil in their 460s. The truck is a 1985 and has atleast 160K miles. The odometer maxes out 99K and it sits at 60K right now. So I assume, along with the previous owner it has turned over atleast once in its life. I do not have the manual for this truck. I am a newbie to old carb'd V8 and trucks in general. I come from sport compacts with aluminum small displacement engines and wrong wheel drive transmissions.

The truck used to be a work truck for an automotive repair equipment business.

What are healthy compression numbers for an 80s era carb'd 460??

 

How many miles on the motor? If the motor is in good shape and it's been using 20W50 it must be OK to continue using it.

Not to say it's never happened but I've never heard of premature engine failure due to using heavy weight oil.

 

I run 20-50 in my 1984 F250 carbed 460 in the summer. Why the 50 part gives a little extra protection when towing and the outside temp is up a bit. I run 10-40 in the winter. But if you live where winter temps don't get to low, it won't hurt in the winter either.

 

Ok cool. Thanks for your answers guys. I was thinking of doing a 15w40, but will just stick ewith 20w50. I live in California, the Bay Area, so temps don't get too low. It doesn't snow where I am at and rarely goes below 40 degrees if ever.