Originally Posted by Uncle Scotty
....I don't think you understand the difference.
Alright, Educate me.
If you really wanted to go all out the you would have to have some sort of compression release like some of the larger insdustrial pieces of equipment. You're sill fighting the compression.
And, yes, I do understand what you are talking about but, how much wear is it really causing? In reality, not much. there is no grinding as the rod and main bearings, if in good shape actually retain some oil. Otherwise, every single car on the road would only last 50k miles.
When I start my car after an oil change I get pressure build up almost immediately up to about 95 psi when cold. Hot and flowing it drops to about 35 psi at idle. I have a mechanical gauge so I know exactly what's going on in there. You can't honestly expect me to think that priming the engine by spining the engine does any good. The only real way to prime an engine is with an "accusump" type device. We use them on the race cars and I'm putting one on my 67 mustang since it will sit for extended periods of time. The oil is kept in a cylinder under pressure and before you fire the engine, you release the valve and the oil system gets pressurized. It also acts as a failsafe if the sump goes dry in corners as it keeps a supply of oil to push through the system.
This is the correct way to prime the engine as none of the internals are moving. You are only building pressure in the oil system. So no, I don't think priming the engine any other way does any good. The interals are still moving and still causing similar wear as if the engine were started in a normal manner.