Synthetic oil on a rebuild?

[illflem]

I assume that it's best to wait till a rebuilt engine is broken in, much like a new one, before going to synthetic. It's not a Cummins. Any input?

 

[RHARVEY]

I have a friend that ran synthetic from day one after a rebuild and not a problem. But I have also heard that you should wait until the rings seat first...



Rick

 

[Roger rodbolt]

illflem,



You may want to check with the manufacturer of the piston rings being used. Great progress made in ring/cylinder wall breakin technology. Generally, if installing new rings on less then new cylinders, a less "slick" oil will improve piston ring seating, but some manufacturers will okay the synthetic.

 

[Skydiver]

I've seen it bone both ways.

Bill in the old days we would use the cheapest 10-30 oil to seat the rings. Then after 500 miles we would use a good grade of 10w30 oil. Only when the engine started using (not leaking)oil we would move up to 10w40 and the engine would stop using oil.

I have a friend that put slick 50 in a newly rebuilt honda civic and it burned oil from that point on.

I talked with a man that had a new Mercedes S430 and he said the car comes with synthetic, modil 1 I think.

On the other hand I have changed from Castrol 20w50 on my 86 Toyota to synthetic at 40k miles and it started consuming 1. 5 quarts every 3k miles.

Sooo I don't know what you (they) should use. I've seen it both ways.

What type of engine is it?

Tim

 

[illflem]

It's GM 3. 5 Vortec. Problem is this is a rig at work that constantly travels the entire state of Montana, big state. It runs between 1-3k miles a week, I'm tried of changing the oil all the time, want to go for extended changes. It's getting rebuilt this week.

 

[drawson]

Bill, Give the new engine three weeks then change to Synthetic oil.

 

[Midnite]

I think I would just put on a bypass filter like a Gulf Coast O-1 jr. or a Franz (sp?). You would just change the bypass element and your regular full-flow filter every 3k. The make-up oil you add when you change filters should keep the oil's additive package up to the point where you could extend drain intervals quite a bit. Naturally, oil analysis would define what your drain interval should be.



As long as you're rebuilding the engine, the added cost of the bypass filter stuff ($150 at most) really is negligible.



Mike