Which oil for a FOrd Crate 351 / 385HP

[bobcowan]

Originally Posted by dan512

I checked and I can get Valvoline VR1 over here in 20W-50 and 10W-60.

I'll give it a try mixing both, should end up with an 15W55.

That is definitely a bad idea.

During start up, a thick oil like 15W or 20W will not lube your engine very well. You've probably heard that the majority of engine wear occurs at start up; and that is generally true. Thicker oil when cold will make that worse.

Viscosity of oil is measured at a standard temperature. a 5W oil will pour like 5 weight oil that's been chilled below 0*. So buy a quart of 20W-50 oil, and put it in the freezer. In the morning, try and pour it out.

Thicker oils when hot do not provide any additional benefit in longevity or performance. The do require more energy to move around, and put more strain on components like oil pump drive shafts and distributor gears. You've heard of people shearing the gear pin, and this is how it happens.

You need a thick enough oil to maintain proper oil pressure in all conditions. Anything more is a waste of energy. Start with a 5W-30 and see what you get. If you're dead set on a heavy oil, use a 5W-40 or 0W-40.

[dan512]

Originally Posted by bobcowan

That is definitely a bad idea.

During start up, a thick oil like 15W or 20W will not lube your engine very well. You've probably heard that the majority of engine wear occurs at start up; and that is generally true. Thicker oil when cold will make that worse.

Viscosity of oil is measured at a standard temperature. a 5W oil will pour like 5 weight oil that's been chilled below 0*. So buy a quart of 20W-50 oil, and put it in the freezer. In the morning, try and pour it out.

Thicker oils when hot do not provide any additional benefit in longevity or performance. The do require more energy to move around, and put more strain on components like oil pump drive shafts and distributor gears. You've heard of people shearing the gear pin, and this is how it happens.

You need a thick enough oil to maintain proper oil pressure in all conditions. Anything more is a waste of energy. Start with a 5W-30 and see what you get. If you're dead set on a heavy oil, use a 5W-40 or 0W-40.

I read you Bob, makes sense too, but then why does Ford recommend 20W50 an why do so many engine builders recommend heavier stuff also?

Not an easy topic I'm tackling here