MEP-016D (Yanmar L70) break in

[stoneburner]

So, after two years, finally got my MEP-016D Yanmar engine rebuilt - I procrastinated getting it to the machine shop, and then the shop took forever. But, got the rebuilt engine back and reassembled the generator. After struggling for a short while with non-start and then backfiring, I found a hose with a small crack apparently letting air into the fuel line. It's running perfectly now. I did some searching on the forum, and I couldn't find an answer to this question, so...

Yanmar says the break-in period is 100 hours. The machine shop left a tag on the engine that says "filled with non-detergent oil to seat rings". When I talked to them, they said to run it for 5 or so hours under load, then change to the regular oil (10w-30, according to the manual). I've only run for about 5 minutes so far just to get things straightened out.

Question: If I follow the manual's 100-hour break in period, what oil should be used? Also, it may take a couple/few years to reach 100 hours of run time. Would I change oil every 6 months or so during this break-in period with the break-in oil until the 100 hours is reached, or just leave the original fill of break-in oil for the entire time, regardless of how long it takes to hit 100 hours?

Or, will the non-detergent oil for 5 hours work, as recommended by the machine shop?

I asked a neighbor who is a diesel mechanic, and he said I should follow the machine shop's recommendations. And, there is all sorts of generic on-line advice, ranging from using special break-in oil to non-detergent oil.

So...what should I do? What will give me the best life out of my rebuilt engine - assuming I don't screw it up again (oil got low during a prolonged power outage, burning up the rings and piston - probably consumed oil because it wasn't broken in properly!)

 

[Light in the Dark]

From this book (which covers the L70): https://www.nuvair.com/manuals/Yanmar-LV-100-Use-Manual.pdf



What 'manual' are you referencing that says 100hrs?

 

[stoneburner]

Interesting - I went and grabbed my Yanmar L-A operation manual - and it says to follow break-in procedures for the first 20 hours - and to avoid heavy loads. But I can't find any mention of "special" break-in oil. I may have seen the 100 hours and arguments about oils in these forums.

Also, the generator has a plate on it warning about varying the engine speed (to avoid damaging the generator). It's basically full RPMS or none. So, I wouldn't want to do that, especially with a load on it since it will change the output and possibly damage the generator and whatever load I have on it.

 

[Light in the Dark]

I know the 100hr mark is for the larger 80X machines that are rebuilt with Lister Petter engines in them. If you are getting conflicting info, you can always reach out to Yanmar directly and see what they have to say. Thats what I would do here.

Contact｜Support｜YANMAR USA

Yanmar America welcomes your communication. This page includes contact information.

www.yanmar.com

 

[stoneburner]

Yes, why didn't I think of calling Yanmar directly? Duh...guess I always try to do things the hard way. I appreciate the advice. I will call tomorrow for sure.

 

[Light in the Dark]

Let us know what they say

 

[stoneburner]

Yanmar’s advice/recommendation for the L70AE (similar to the N, V, or W engines) is to break in using the regular, recommended oil viscosity meeting at least the minimum API-CJ4, ACEA E6, and JASO DH-2 service categories found in the operating manual (the attached manual applies to the L70AE used on the MEP-016D and other military generators, provided by Yanmar tech support).

Break-in period is 50 hours under moderate/varying load at the full 3600 rpm

For my use, I likely won’t hit the 50 hour mark for more than a year, in which case, oil should be changed at least annually, regardless of hours. After the break-in, change oil as recommended every 200 hours or annually.

I did ask about special “break-in” oil, such as that sold by John Deere. The person at Yanmar said there’s no such thing as “break-in” oil. According to him, it’s a gimmick.

I will be draining the non-detergent oil currently in the engine and replacing with the standard oil recommended in the manual - most likely 10w-30 or 15w-40.

 

[Light in the Dark]

Well I respectfully disagree with their statement that break in oil is a gimmick. It lacks friction modifiers to allow slight wearing of components so they all seat properly. But I am glad you got an answer on hours to break in.

 

[Poccur]

It lacks friction modifiers to allow slight wearing of components so they all seat properly.

That is exactly what they John Deere service folks told me. They said if you go straight for the high-end oil with all the clever additives the components do not get hot enough to seat. Basic oil for break-in period then you can use all the really good stuff from then on...