Engine oil for new rebuild?

What break in engine oil is being used on a diesel engine that normally runs SAE 30? Is it correct to run non detergent SAE 30 for roughly 50 hours?

Tend to agree with Boss Man. I don't do much of this so not an expert. A recent experience was 454 GM in a pickup. Bored 30,new pistons and rings and put 10w30 synthetic in it from the start. Never used a drop and oil stays clean.

My understanding is todays oils do not have zinc which is critical to engine break in. I found non detergent SAE 30 wt Valvoline. I also saw a zinc additive that you can add to the oil.

I worked as a diesel mechanic in a large shop for over 20 years, im not claiming to be an expert, but i have rebuilt a lot of heavy truck diesels. We would do at least 1 overhaul a week, not always me.
But we just put our normal stock oil in it 15 w40 , nothing special.   Then those engines were expected to run 700,000 to over a million miles, and they did.
First oil change on them was at 8000 miles, which was way early for us. Those weren’t farm tractor engines, but we’re heavy duty engines that had to pull all day and night. We didn’t put any additives or anything but our regulator oil in them, and they lasted seemingly forever.   
Don’t know if that helps you or not, but that’s what we did. Was standard procedure.
Good luck.

My new Cub Cadet had a 10 hr break in oil in it. Not sure what that was, but maybe small motor requires it.

There should be no need for a detergent oil in the beginning as the engine if done correctly should be spotless inside. My engine builder cooks the block to do a thorough cleaning so he is starting with a clean block and components.

I've had good luck with John Deere Break-In Oil.  I think it is a 10w30?  But it is formulated for remanufactured/rebuilt engines to help with break-in.  Not very expensive compared to regular 15w40. 

I run a fleet of bucket trucks and we use nothing but 15w40 Castrol in all of the big trucks. New & old. The pickups I use 5w30 synthetic.  Our bucket trucks have way over 20,000+ hours on the engines with no failures. Our trucks don't put a lot of miles on them. Its more hours than miles, although some of our trouble trucks that run darn near 24 hours a day through two shifts have darn near 300K miles on them. I think if you put in 15w40 and use it from day one you'll be fine. JMHO. Today's motor oils have a lot more lubricants in them than 20-30 years ago....

JD break in oil is available everywhere and in gallon jugs. Use it on rebuilt engines because today's oil is so good with additive packages the rings may never seat. The zinc is for flat tappet cams, and like red bank mentioned, shaft rockers probably benefit from it too. Anything metal to metal will like zinc. The alloys in the new parts has also seemed to be harder. I never used to have trouble seating rings, but in the last 10 years it's been a big issue, kinda like the old days when they had chrome rings and chrome liners, they would have to use Bon Ami to help seal them up. lol!

From what I have read Zinc is the key. I’m going to do some more research on this Valvoline SAE30 non detergent to make sure it has Zinc in it. Ed, my engine builder said the same thing as far as having a harder time breaking engines in with todays oils. That’s the whole purpose of this thread is to get some good information from anyone familiar with a new rebuild. I don't want to mess up a big investment by putting the wrong oil in it.

The JD oil is reasonably priced as well. Reliance has a specific break in procedure they recommend to prevent the failures like what many have been experiencing. Reliance offers a break in oil as well. I use Schaffer break in oil too in my own rebuilds. 

Good point, I learned long ago to do this, but I use ATF, as it's high detergent. The tractor in question would have sleeves that were replaced though. 

I called Valvoline support line and the SAE 30 non detergent oil does have Zinc in it. I will look into the JD oil, but it sounds like the Valvoline should be fine. I looked at Lucas SAE 30 engine break in oil online and that looks like a good product as well.

Edited by AC720Man - 04 Aug 2021 at 9:42am

Check with your dealer

I used the JD breakin oil when I rebuilt my WD45. No problems.