Yanmar 4JH3-TE vs Beta Marine 60

[Dockhead]

Originally Posted by Scubaseas

A compression test will not tell you the condition of the oil scraper rings unfortunately. Nor is it as good an indicator of ring efficiency as a cylinder leak down test would be. . .

Neither compression nor leak-down tests are really all that necessary in small marine diesels.


You can tell immediately whether compression is good by how well the engine starts and whether it runs smoothly. If it starts up easily and runs smoothly then the compression is OK.

[Shaneesprit]

If not using synthetic oil try that first and see if improves oil consumption. Full synthetic will usually stay in a motor with weak rings longer. One indicator of worn oil scraper rings is if it uses more oil the further away you get from your last oil change.[/QUOTE]

I will go a bit further on this, what oil are you using?
Did you change your oil brand?

Cheap oils burn away, so don’t be tempted to use cheap oil.

[Scubaseas]

Originally Posted by Dockhead

Neither compression nor leak-down tests are really all that necessary in small marine diesels.


You can tell immediately whether compression is good by how well the engine starts and whether it runs smoothly. If it starts up easily and runs smoothly then the compression is OK.

I don't disagree, sort of. Cold staring especially in low ambient temps like 45*F can prove hard with a motor that starts well at 75*F. My post was meant to be in relation to the efficacy of using a compression test to asses oil scraper ring condition. The compression rings have little to do with oil consumption and a compression test will tell you nothing about the oil rings which can contribute to oil consumption.

As far as the OP's question I see the posts regarding breather system and turbo as sources of the oil consumption.

[Scubaseas]

Originally Posted by rostyvyg

The compression test was good. But doesn't it only show the state of the compression rings? If oil rings are shot the compression should be fine but oil will be leaking into the cylinders, right?

Right.

[JCFlander]

Hello, In addition to aforementioned reasons, high oil consumption can be also due to glazed cylinder bores. In other words, the oil-retaining crosshatch pattern on the walls is saturated by varnish, and cylinder wall does not retain oil as it should and it gets to combustion chamber. See details on link.

That can be caused by:

- Battery charging on neutral (typically very light load)
- Oversized engine with long waterline, engine runs 10-40% load on cruise
- Engine oil with lots of low-friction additives ("eco") and/or high base number (longlife) ->glazing, corrosion.


Quote:
"An engine...should never be run at light load for long periods, as is typically done for yacht battery charging. In the middle part of its life, glazing is less likely while the bores remain in good condition, although as wear increases its likelihood will increase. However, bore polishing is always a possibility with light loading. The solution is always to load the engine when battery charging, by driving the propeller."
http://coxeng.co.uk/engine/bore-glaz...iesel-engines/


Cylinder walls can be readily inspected when cylinder head is removed. Short of that, borescoping through injector hole might work.
If crosshatch pattern is gone, cylinder bores need re-honing. If the quoted price is too steep, then a similar new engine that requires minimal modifications might be a better investment.

If I had a similar situation, after rounding up the usual suspects like turbo oil seals and clogged breathers, I would try either:

- Yanmar's own 15W-40 oil, if used something other previously. Consumption might change due to thicker oil.
- Some synthetic oil that is advertised to work well on "vintage vehicles". Consumption can be a bit less due to viscosity additives.

HTH, cheers.

[sinnerman]

Originally Posted by Northernbrewer

Not sure if the 3JH4E is similar, but ours started burning oil a couple of years ago. If memory serves it was about a litre every 10 hours. It turned out that the problem was the breather diaphram and spring. Parts were about $50, labour much more.


Cheers
--Neil
Waterfront IV

I had a friend who bought a SAAB (900?) for pennies since the owner could not solve the burning oil / blue smoke issue.

It was the exact same problem broken diaphragem (acutally a cheap plastic disc) in the breather system...

cheers

[sinnerman]

Originally Posted by rostyvyg

The exhaust does not look too sooty. It emits some blue-grey smoke upon startup, then the smoke dissipates when the engine warms up.

And I don't know how to check the oil cooler for leaks, - it is in an inaccessible place below the turbo, but I would assume there would be oil sheen on the water if it was leaking, right?

Oil Sheen: Probably not.

My diesel was losing engine coolant. I tried everything to locate the source, even putting ultraviolet (UV) dye in the coolant and watching the exhaust at night with a UV light looking for traces of the dye.

No evidence.

In the end, I removed the HX (engine cooling, not the oil HX). and had it tested and it was confirmed to be leaking internally. Since the raw water flow was so much it diluted the dye.

The same for your oil HX. It can be leaking in small amounts and the oil will be finely dispersed by the raw water flow.

The oil pressure is much higher about 40 psi.

The leakage path will be from high pressure oil to low pressure raw water..

Well anyway, that is my two cents.

Cheers

[nmccubbin]

We have a Beta 60 in our 14 ton Passoa 47
Very pleased after 10 years use, 2500 hrs
It is plenty big for your boat