MAN Compression specs for D2840LE-401

If the question is academic, contact a MAN service shop. If you are concerned about the report of a compression test, the operative question might be "does it start easily when cold?"

As long as the engine starts easily there is adequate compression. If other factors like injector condition, fuel quality, and cranking speed are not an issue and the engine starts quickly, compression is not something to worry about.

I would have a leak down test performed. Don't know MAN specifically, but usually 15% is the max variation allowed between cylinders. You can also do the compression test again, after adding a small amount of oil to the cylinders. If that brings compression up, you have worn rings, if not, valves need some work. Also, too little valve lash (worn seats) can keep valves from closing fully and lowering compression. I would think a good survey would check all of this though?

With that information I would ask how much running the engine(s) have had recently. Have they been sitting for an extended period or have they been in regular use?

Reason being that if they were sitting for considerable time it is possible one cylinder has some surface rust on the rings or bore. A period of hard running might completely change the readings for the better. As the other poster mentioned, a leak down test will help identify rings or valves as the source of low compression if it does not come up after a good run.

In any event, a "major" is not necessarily in the cards given the description you provided. You might even get away with doing a single head and valves.

I'm not a fan of working on Man's.....They just never fix their design flaws......upside down spring loaded canister oil filters that always make a mess and are a 2 person operation to get on. (I've done it by myself but they're a pain). They have the same **** oil filters on the 1942 U boat that's sitting in the Museum of Science in Chicago.......Threadcerts on iron parts that always come out with the bolts on the oil filter and fuel filter bolts. Never relocating filters to the Aisle.......LOTS of electrical issues which are design flaws yet they never take accountability for and make the owner pay for it. Sensors that go bad far too often and are expensive. The electrical is their real pain or weak knee. Engine controls that they knew would screw up sooner than later, and never warrantied....But the "updated" ones have chrome through the center hole all of the way.......I'm so tired of hearing "It's not covered under warranty, but he have an UPDATED part". Even MTU now uses spin-on oil filters.......OHHHHH and the very best was the high pressure injector line on the old 1050's and 1350's that would break off because of a bad design and the engine harmonics and shoot fuel ALL OVER the entire engine room and dump 100's of gallons in the bilge, the ceilings, the walls, that they knew about for 2 entire years and never recalled nor covered if it made it out of warranty. When one engine blew the high pressure line, the other was going to within 3 months and 50 hours also. But after they waited until their entire inventory of the old ones was depleted, they then redesigned it with an "updated" part. Everyone designs bad parts sometimes, but don't stick it to the customer, take some accountability for your mistakes, especially something as dangerous as a high pressure fuel line.

They do run quiet and are fuel efficient........