Engine oil wt. and quantity, 1973 302.

[johnbeck]

I have a thousand miles on my just rebuilt 302 with 250 hp. I broke the engine in with 15/40 rotella non synthetic. What weight synthetic should I use? I'd like to put the right quantity for a 1973 stock pan and short filter. What quantity(Having the right quantity in the engine will help me scribe on the dip stick where full is)? Thanks so much,John B

 

[DirtDonk]

Never checked the difference between a regular and a short filter. But the official rating of a stock bronco V-8 pan (for all years if I’m not mistaken) is 6qts.
If you use 5 1/2 quarts with your small filter I’m sure you would not be improperly filled.
By the way, what is a small filter? What size, what part number, and got pics?

Was your engine built around the use of synthetic oils? If not I would wait for maybe 5000, or even 10,000 miles before switching.
Yes, many modern engines run with synthetic right from the factory. But in the old days the rule of thumb was not the initial run in of 500 to 1000 miles, but instead giving rings and things the time to fully seat, such as 5000 to 10,000 miles.
That’s still my practice anyway. I’m sure you’ll get very a wide variety of suggestions.

You can run anything from a 10w/30 (or even 5w/30 in a colder area) to a 20w/50. I happen to like the 15W/40 that you’re already familiar with. I’ve read a lot of threads here where people with the thinner oils such as the 10W/30 were commenting on the oil pressure being lower than desired. Even on a fresh rebuild.

 

[Broncobowsher]

Need to know what oil pan was used. The engine doesn't hold the oil, the oil pan does. They come in different sizes. Mustang twin sump is 5 quarts and Bronco stock is 6 quarts (both with new full size filter). There are aftermarket pans that hold different amounts as well.

A good tight new engine will probably be happy with 5W30. Thin enough to flow easy and drain back good when cold, but thick enough to have an oil film. Typically the engine builder will spec what weight oil to use. If not speced, I like to go as thin as possible and still have good oil pressure when warmed up. That way it flows good. 250HP isn't a high stressed engine, don't need super thick stuff to try and keep a film under severe loads.