What oil on fresh rebuild?

[Purdy Swoft]

Originally Posted by captain j

What harm would it be to use a non Detergent oil anyways? Napa carries it. I understand with all of you guys using detergent oils that I'm sure it's fine. I don't want to go against the builder and have issues

Non detergent oil lets all the crud to settle in the bottom of the oil pan and valve chamber. Non detergent usually doesn't have any anti wear additives and I've never seen a multi grade in non detergent. On the other hand I ran non detergent in my sept 29 engine for probably forty years with no problem other than heavy crud build up. As for the babbitt, this engine still has the original babbitt and I have owned it since the spring of 1960. I now use Walmart 20w50 high detergent. Detergent oil keeps foreign particles suspended so they are drained out with oil changes instead of collecting in the low spots in the engine.

As others have said, its best to use whatever the rebuilder recommends if you expect to have any warranty. The last 350 GM crate engine that I bought, the parts man said to break it in with 30 weight non detergent for the first thousand miles and then change to a good detergent grade oil. The thought was that some wear is needed for the rings to seat. Non detergent has no anti wear additives and helps speed up break in..

I overhaul my engines and have nobody to answer to !!! I use 30 weight non detergent for break in. On first start up, I run the engine for 20 minutes and shut it down. I then retorque the head and change the oil. I then run put about 100 miles on it and change the oil again. I change the oil often untill I get about a thousand miles or am satisfied that the rings are seated. After that its strictly high detergent oil only. This is just how I do mine. Don't do what I say, do whatever the engine builder says because he is where responsibility falls. This is just what works for me. Oil is cheap compared to engines. The drained oil works good in son inlaws worn back hoe hydraulic system so that I have no problem with waste oil.