How to make your Diesel last a long time.

[hellosailor]

Chuck, I would suggest the first question is whether the oil is being consumed internally--versus leaked externally. If you start with a clean engine bay and fine no evidence of external leaks (bearings, covers, anyplace?) and no oil trickling down anyplace, it is being consumed. And then the only question is where or how.

Could easily be just getting sucked past the rings. I don't know that engine, perhaps the break-in hours weren't run quite right. Or perhaps that engine is just supposed to consume oil. Mercedes used to build diesels with loose rings, intentionally. They said if they used loose rings and consumed a little oil (a liter/1000 road miles) the rings and cylinder walls would last forever, and that fresh oil was a good cheap way to get engine longevity.
Could be worth asking the maker what is normal for your engine, before looking to see if this is not.

[Alan Wheeler]

I reckon a car averages around 75kph on a trip.

Based on the fact that the boat engine is providing a constant RPM unlike the car that the RPM and gear ratios are greatly varying. So I losely base my assumption on a road speed of 100Kms/hr.

[AnchorageGuy]

The engine has just seen a trip from Guatemala to Houston Texas and the entire trip of over 1000 miles on the Gulf ICW was under power so it has been run a bit. 1/4 of a QUART. Break in was done according to Yanmar specs. I am a Marine Tech so have been around boats for over 35 years. Have a good idea on break-ins and oil changes.
Prop is correct for the engine and the boat. She runs a the proper RPM's. Will max out at 3500 which is where it should be. There are absolutely no leaks on this engine of any kind so it has to be internal. I know from years of experience with Yanmar's that if the engine is in good order it should not use oil, so that is the reason for my question. The 15W 40 oil is the proper oil for the engine. I have considered the break in period to seat the rings but would have thought they would seat by now. Considering the extensive running the engine gets. From Isla Mujares to Marathon was 2 1/2 days of constant motoring at around 2900 (that's RPM's for Ex-Calif) then a long haul to Texas. Use never got better or worse. Just has me baffled right now.

[hellosailor]

Oh, heck, if it is down eight ounces after a thousand miles?! What is that, 200 hours of operation?

I guess you could do leakdown and compression tests if you really wanted to check the cylinders out, but I suspect Yanmar will say that is within normal operation. Call 'em direct and see what they say.

[AnchorageGuy]

hellosailor, you have an echo. I wish we could travel 1000 miles in 10 hours. More like 60 to 75 miles in a ten hour period then add about 1/4 of a quart of oil. Actually after running for 2 1/2 days we added just over a half a quart so no rhyme or reason.

[Ex-Calif]

Originally Posted by Chuck Baier

ten hour period then add about 1/4 of a quart of oil. Actually after running for 2 1/2 days we added just over a half a quart so no rhyme or reason.

Well it's not leaking and it's disappearing. Not to state the obvious but it has to be burning. That means valve guides or rings. No magic.

With the age of the engine I'd say rings. If the consumption is not consistent that is perplexing. Sorry to be a stickler about the measuring units but you really can't mix days with hours and pints and quarts.

Unless of course you mean

8 ounces in 10 hours and
16 ounces in 60 hours (2 1/2 days)

Sorry to be a pinhead about this.

[hellosailor]

Chuck-
I think you've got Dan & I both confused about how much got burned up how fast. But if it is that inconsistant...that IS odd. Time to speak to Yanmar and do some testing, I guess. If the load and engine speed were consistant--the consumption should be. Any chance there was a serious change in speed or wx that could account for a changing load being part of that?

[AnchorageGuy]

Dan, You have the quantities down right. I have considered valve guides and even possibly rings but this engine was installed in this boat as a repower and was brand new. The vanishing oil has been since day one and every Yanmar mechanic at the beginning said this would quit once the rings seated. Could they possibly not be seated after 1200 hours. We have maintained the engine operated it since day one.

[AnchorageGuy]

8 ounces in 10 hours and
16 ounces in 60 hours (2 1/2 days)

This is the correct amount being consumed and not exact. Might be a bit less or more but pretty close. No change in weather, speed, sea conditions or anything else. None of these factors change the oil consumption. we have motored in flat seas, motorsailed in moderate conditions and pushed hard in near gale force conditions and the consumption is usually pretty close to the same. I guess my only issue with the oil being burned is this engine shows NO smoke or any kind of soot on the stern.

[Alan Wheeler]

What oil quality are you using?? Cheap oil can be used up faster than a good quality. Although I assume you are using a good quality seeing as it is you Chuck.
Here is a good question though, Do you notice if consumption increases toward the end part of it's service life. Dirty Oil can cause it to be burnt faster. I have often noted that an engine can use little oil and then suddenly the oil use increases and I realise the change time has arrived.
Leaky valve guides produce quantities of blue smoke at certain points of operation. The main one being startup. I doubt this will be the issue at such a low eng hr. Most likely she is still bedding in, although this should have happend by now and I go back to my original comment. However, I do not consider this quantity of oil being used as exccesive enough to worry about the engine not having bedded in correctly. I think you will have many years of good work and reliability ahead.

[AnchorageGuy]

Thanks Alan. We use a good quality oil and the lack of any smoke is one of the mysteries. There is no difference in consumption whether it is the day after an oil change or as she approaches 100 hours. I am not too concerned since it has performed so well for us. Just thought maybe someone had a clue that we had not considered. After virtually tens of thousands of miles I am not going to get too worked up about it.

[hellosailor]

Chuck, my only concern would be whether it could be something significant, i.e. if the oil was being pulled past the beginnings of a head gasket failure--only when the engine was at a certain operating temperature, etc. Or into/through some other odd way, due to thermal changes.

[hellosailor]

I see I have an echo again...and this time, I KNOW I only hit the "post reply" button once.

[Nauticatarcher]

From my Fishing Days, an Oil burn rate of 1% of fuel consumption was OK, oils cheap, unnecessary overhauls aren,t

[Alan Wheeler]

Hey Nauticatarcher, great to see you here. How's sunny Nelson???
I finaly got around to actually installing the VHF last weekend. I just down loaded the instructions and am reading them. Hmmm, complex little beast eh.