Smoking Yanmar

[bignick]

I was going to say the same thing - worth changing the oil. It should be a mineral oil - if someone has “upgraded” to semi or full synthetic then you can get bore glazing, which can result in lower compression and some oil burning.

 

[oldgit]

A review of a 4 cylinder Yanmar.
ENGINE REVIEW - YANMAR 4LHA-STP

 

[westernman]

A review of a 4 cylinder Yanmar.
ENGINE REVIEW - YANMAR 4LHA-STP

Not at all the same engine range as the 4JH2 series of engines.

But one thing in common is the following paragraph:-

Yanmar recommends specific diesel engine sump oil at SAE 15W40 for all ambient temperatures and I’d suggest changing the oil and filter every 100 running hours or annually. Like all mechanically injected diesels, the STP should not be run continuously below its maximum torque band or excessive injection advance could glaze the cylinder bores through unburned fuel. Mechanically injected diesels must be worked to maintain a long service life.

 

[Easysquezy]

It's been over a year since I posted to this thread. We motor sailed the boat, Hunter passage 42 with Yanmar 4JH2 TE to Everett from San Francisco. Did many extended hard runs. Nothing cleared up, burnt about a quart every 24hrs of run time. Motor has a little over 1200 hours. I think the motor has suffered to many years of none use, harbor rusting, glazed cylinders and a couple old impeller overheatings? Has anyone ever rebuilt one of these inplace? Or good suggestion for replacement.

 

[ducked]

If the rings are sticking, a soak with a teaspoon or so of brake fluid per cylinder might help to free them up. Maybe do this before an oil change, (since the oil might be contaminated by the brake fluid) followed by the Italian tune up as recommended above.

If you can arrange to feed a distilled water vapour mist (Or steam is probably safer : my engine is quite close to the galley stove so hooking it up to a kettle would be fairly easy to arrange) into the running engine during the Italian tune up this might help too.

Very important to avoid significant volume of liquid water ingestion though, which could cause hydrolock damage. There may also be a possibility of spalling damage due to thermal shock with liquid water. I've never seen this discussed but may have seen it.

Of course this decoking wont help with bore glaze or wear, which would require a rebuild.

 

[Beneteau381]

Rule of thumb with small diesels - black smoke = injector, pump or timing problem, blue smoke = worn rings / bores, white smoke = low compression.
First I'd do is a good 30 minutes at full throttle under max load - if during 30 minutes revs rise, things are looking good.

Really?

 

[Beneteau381]

If the rings are sticking, a soak with a teaspoon or so of brake fluid per cylinder might help to free them up. Maybe do this before an oil change, (since the oil might be contaminated by the brake fluid) followed by the Italian tune up as recommended above.

If you can arrange to feed a distilled water vapour mist (Or steam is probably safer : my engine is quite close to the galley stove so hooking it up to a kettle would be fairly easy to arrange) into the running engine during the Italian tune up this might help too.

Very important to avoid significant volume of liquid water ingestion though, which could cause hydrolock damage. There may also be a possibility of spalling damage due to thermal shock with liquid water. I've never seen this discussed but may have seen it.

Of course this decoking wont help with bore glaze or wear, which would require a rebuild.

Wow!

 

[Beneteau381]

Not at all the same engine range as the 4JH2 series of engines.

But one thing in common is the following paragraph:-

The OP admits to light useage, an Italian tune up would I suspect help. Nobody seems to have said if it is using excess oil, plus what type of oil is in it?

 

[ducked]

Wow!

Wherefore and whence with the Wow?

 

[ducked]

Manual for my Yanmar 1GM10 says oil of API CC or higher, 15W40, with a TBN >9 (Total Base Number. 9 is pretty high), my kind of oil, though probably more widely available in Taiwan than in The Yook. I have 4 unopened L of nice Mobil MX 15W40 there that would do nicely but will probably end up in the recycling now the cops have got my car

Interestingly, if you like that sort of thing, it also says “Never use API Service Category CG-4 or CH-4 oils.” so I guess that means CC, CD, CE, or CF, assuming they all exist, only. Wonder whats wrong with G and H. Perhaps no ZDDP?

Since I wanted to change the oil before I left for Taiwan, and was thus in a hurry, I had to resort to Halfords, who once again "needed the registration" and predictably had never heard of TBN, and couldn't think of a single entity in the organisation that might have.

So they sell a technical range of products, but apparently dont have any mechanism at all for fielding or raising technical queries on them. Knock me dahn wiv a fevva.

I put some of thier 15W40 in it. If, as seems likely, I cant find out the specs, it should still be adequate for a short term flush.

 

[vyv_cox]

Manual for my Yanmar 1GM10 says oil of API CC or higher, 15W40, with a TBN >9 (Total Base Number. 9 is pretty high), my kind of oil, though probably more widely available in Taiwan than in The Yook. I have 4 unopened L of nice Mobil MX 15W40 there that would do nicely but will probably end up in the recycling now the cops have got my car

Interestingly, if you like that sort of thing, it also says “Never use API Service Category CG-4 or CH-4 oils.” so I guess that means CC, CD, CE, or CF, assuming they all exist, only. Wonder whats wrong with G and H. Perhaps no ZDDP?

Since I wanted to change the oil before I left for Taiwan, and was thus in a hurry, I had to resort to Halfords, who once again "needed the registration" and predictably had never heard of TBN, and couldn't think of a single entity in the organisation that might have.

So they sell a technical range of products, but apparently dont have any mechanism at all for fielding or raising technical queries on them. Knock me dahn wiv a fevva.

I put some of thier 15W40 in it. If, as seems likely, I cant find out the specs, it should still be adequate for a short term flush.

If API CI-4 is available I suggest you use that. Quite possibly the best oil grade available today.

Bear in mind that when the Yanmar spec was written, diesel fuel contained sulfur at a relatively high level. This is no longer the case, relaxing the TBN requirement considerably. API CI-4 was formulated to account for this.

 

[ducked]

If API CI-4 is available I suggest you use that. Quite possibly the best oil grade available today.

Bear in mind that when the Yanmar spec was written, diesel fuel contained sulfur at a relatively high level. This is no longer the case, relaxing the TBN requirement considerably. API CI-4 was formulated to account for this.

Well, in the abscence of any update from Yanmar I'd tend to go with the latest info I have from them. particularly as later spec oils are likely to have lowered levels of ZDDP, which might be harmful

Mobil Delvac MX, 15W40, for example,"meets or exceeds" CI-4 (Mobil oils dont seem generally to actually be API certified) but is TBN 9.2, so in that example I suppose both those bases are covered (NPI).

Are you suggesting there is actually something wrong with a high TBN?

I did find a single email from a Mobil rep to some Jeepster site that attributed a decent level of ZDDP to it, but thats a long time ago, and like most oil companies about most oils, they say nothing now, so it may no longer be true, and I would probably prefer not to chance it, given a choice.

I think the Halfords stuff was CD (?) and completely undocumented Mystery Oil, though probably not a Marvel.

 

[Refueler]

4-107 fitted to my boat near 20yrs ago - replaced the 4-99 .... previous owner of the 4-107 removed it for being smokey ...

It sat on a pallet in HYCO for couple of years at back of shed.

We dusted it off ... 250 quid paid ... fitted to my boat (that cost a bit though !!)

Gave it a good thrashing round the harbour ... smokey - yes ... but soon started to clear ...

Still running sweet in the same boat ... yes it has its smokey moments if boat not used for a while ...
Being overpowered - if I give it full throttle - it chucks a bit of black stuff staining transom ... but that's expected. But as long as I give it a blast every now and then - she is good as gold ... with just a faint wisp ....

 

[Boater Sam]

Take the air filter off. Let it suck in plenty of dust. My old mate used to chuck a handful of castor sugar in when the engine was running flat out. He claimed it stripped any gazing off the bores. Seemed to work.

 

[vyv_cox]

Are you suggesting there is actually something wrong with a high TBN?

Maybe. You won't find any literature on this but I knew workshop people at Dickies of Bangor quite well. They carried out some test work that showed high TBN oils seemed to be responsible for higher bore wear rates. This was a long time ago when raw water cooled engines were more common, so there could be a link with lower coolant temperatures.

Some time later I worked in the Lubricants department at the research centre of an oil major, although I am not a lub specialist. I asked people who really knew their product and it was confirmed that high TBN and low coolant temperatures could cause bore wear with some additive packages

Time has moved on a lot now but it seems to me that if high TBN can be avoided it will do no harm.

 

[ducked]

Take the air filter off. Let it suck in plenty of dust. My old mate used to chuck a handful of castor sugar in when the engine was running flat out. He claimed it stripped any gazing off the bores. Seemed to work.

I'd expect that to form "instant coke" . Maybe it does, and this fills in the ring gap and restores compression.

If so it would probably not be for very long, though

 

[vyv_cox]

Manual for my Yanmar 1GM10 says oil of API CC or higher, 15W40, with a TBN >9 (Total Base Number. 9 is pretty high),

Something odd there. When I owned a Shell lubricants manual 20+ years ago the TBN of API CC was 3 and CD was 4.

Some oils to the CG and CH specs had TBN values somewhat higher, ISTR 16 or so. Maybe this is the reason Yanmar don't like them?

Cylinder oils for large marine engines, total loss with separate crankcase lubricant, have TBN around 100!

 

[ducked]

Something odd there. When I owned a Shell lubricants manual 20+ years ago the TBN of API CC was 3 and CD was 4.

Some oils to the CG and CH specs had TBN values somewhat higher, ISTR 16 or so. Maybe this is the reason Yanmar don't like them?

Cylinder oils for large marine engines, total loss with separate crankcase lubricant, have TBN around 100!

Well IIRC Yanmar specify >9. Dont think they specified a maximum.

Didn't know about those in-cylinder oils, sounds a bit like the same role as 2-stroke, protecting the bore and rings.

I wouldn't have thought it would need much acid buffering in that location under total loss operation (though I suppose the bunker fuel is fairly horrible stuff) and so I'm surprised TBN is quoted, unless its an anti-wear and/or detergent agent that just happens incidentally to be highly alkaline?

 

[vyv_cox]

Well IIRC Yanmar specify >9. Dont think they specified a maximum.

Didn't know about those in-cylinder oils, sounds a bit like the same role as 2-stroke, protecting the bore and rings.

I wouldn't have thought it would need much acid buffering in that location under total loss operation (though I suppose the bunker fuel is fairly horrible stuff) and so I'm surprised TBN is quoted, unless its an anti-wear and/or detergent agent that just happens incidentally to be highly alkaline?

The TBN is not quoted. I worked on a power generation engine in Macao in conjunction with lubricant specialists. The TBN was a factor in problems the engine was having. Fuel was good quality diesel.