White Smoke - Still - I give up

[mickp]

Thankyou to those who replied to my previous post on the white smoke problem. I have so far replaced exhaust system, had injectors and fuel pump serviced, tried without air filter, altered pump timing advance and retard, none of this has made any difference. The oil is good - no water, the cooling is ok levels not gone down, engine starts first time every time, runs well, temp and oil pressures perfectly normal, from this i assume that compression must be ok, head gasket must be ok. So what else can i try ??
If i continue to run engine when all is as above will it do any harm ?
Engine is a Thorneycroft T90 / BMC 1.5 Deisel

 

[ccscott49]

Injectors, filters etc, have nothing to do with white smoke, its water, not unburnt fuel. If the cooling water level is OK, thenit must be raw water, the only place raw water comes into the engine, is at the injection elbow at the exhaust, I would want to check the flow at this point, there should be a constant flow when the engine is running, you can insert a piece of plastic hose at that point and observe it, under no circumstances disconnect this hose to observe it for more than a few seconds, you will; burn up the exhaust system and your boat! If the engine is not overheating, then whats the big problem? You will; always see some white smoke from the exhaust. But it is probably a slightly blocked water way to the exhaust thats the problem and you are getting insufficient flow, to adequately cool the exhaust gases. There is one time you will get white smoke, not from water, thats when you turn the engine over for a long time, whilst it doesn't start, then white "smoke" from diesel will emit, thats not the case with your engine.

 

[mickp]

Thanks CCS, the elbow which was of a home made nature was replaced with a proper thorneycroft elbow and at the same time the manifold was removed and cleaned, when re assembled new hose and water trap were added. The system chucks out plenty of water from exhaust outlet. The exhaust pipe does not even get warm. Incidently the inlet seacock and strainer plus hose to engine were all changed a few months ago, and the water pump serviced, however i will monitor water flow.
What i ommited was the engine had been idle for 6 years prior to me purchasing the boat, so does it just need a good run like say motor accross channel for ten hours at max speed ?

 

[ccscott49]

It wouldnt go amiss to have a good blast, as it often helps, I would still like to know, just how much white smoke or steam are you getting? Is the engine misfiring? I would take a competent mechanic with me or in company with another boat. I repeat, it is quite normal to have some steam emitting from the exhaust.

 

[pvb]

Don\'t give up...

My Volvo 2003T chucks out lots of white smoke. The oil's fine. The cooling's fine. The compression has been checked and it's fine too. Don't worry - if it's working OK, leave it alone.

 

[vyv_cox]

I can't speak for your engine, but Bukh 20s all steam. Mine had a new trap, plus hoses and silencer in as-new condition. Always steamed. I reckon it is some combination of the manifold water inlet position/size and the amount of water flowing, relatively low with the Bukh. Now I have a Yanmar 27, all the exhaust system is unchanged (except the manifold) and the water pump is a size bigger. No steam at all.

 

[oldharry]

If the engine has stood idle for 6 years then it will very likely chuck out smoke for a while, and your suggestion of a good blast across the channel may well prove effective.

We obtained an old Sherpa diesel van with a 1.8 BMC one time, which had stood for several years. It smoked - did it just! In for MOT it fogged out the workshop - you could hardly see the door, but the emissions computer after refusing to read it at all 3 times then beeped out 'pass'! A voice from the office, (wgere the boss had retired in disgust) called out 'turn it off quick before the thing changes its mind....'

We then set off down the road leaving a smoke screen worthy of a Hollywood naval epic. 20 miles down the motorway (at top speed of 55mph!) it was running clear, and never smoked again!

I ran a motor sailer for quite a while with a BMC 1.5, and although there was plenty of coolant, it always gave off some steam. The proof was that on a hot summers day there was less steam than a cold spring morning!

And for the corrspondent who said that white smoke is 'nothing to do with injectors' - it is the normal symptom of injector or compression difficulties - as long as it is smoke and not steam! It is very difficult to tell the difference in a water cooled exhaust, as they both look and smell much the same. White Diesel smoke - which is actually atomised diesel oil from the injectors passing through the engine unburnt - is rather more pungent, but DONT go sticking your hooter up the exhaust to sniff the difference!!!!!!!

 

[ccscott49]

White Diesel smoke will only be emitted if there is no combustion atall on that cylinder, I did ask whether the engine was misfiring. If it isn't, then it would chuck ou black smoke, as in partially unburnt fuel, which of course could be caused by faulty injectors or compression. But as he never mentioned a misfire, I didn't take this into consideration. All this IMHO of course, it's difficult to do long range fault finding as I've mentioned before.

 

[Guest]

Mine\'s got better this year

I have a raw water cooled Volvo 2001. At the end of last year I was all white smoke ( I think steam) with only a medium amount of water going through.

In the winter,drained the water from the plug in the block and had to dig out a load of mud (East Coast) out before water gushed out. The return pipe from the galleries to the exhaust elbow has a small bore hole to the return. This was also gummed up. I changed the half inch inlet pipe at the seacock to a 'full bore'.

Water is now coming out of the exhaust like Niagra Falls with no white smoke at all.

The water is coming out very cold but the engine feels warm to the touch. Would be very grateful if anyone could tell me if this is ok. Does the inlet bore have to be a certain size ?

Hope this is of some use.

 

[ccscott49]

Re: Mine\'s got better this year

The thermostat in your engine will/should keep it operating at the correct temperature, so I wouldn't worry, the more (water) the merrier as far as I'm concerned, keeps everything flushed through.

 

[kgi]

sorry i came in late on this post does it blow white smoke all the time, or just after start up,? if its just after start up what i found on my engine was it was the valve stem seals. i dont know if thats any help...

 

[PeteMcK]

Valve stem seals

One of the posts below reminded me that most of the B-series engines' valve stem sealing arrangements are pretty rudimentary (in fact, I can't believe the "seals" actually function as seals at all). This certainly caused the petrol versions, even in low-mileage cars, to give off clouds of light blue smoke when accelerating after, say, long descents with the throttle shut, or very long periods idling (conditions of high vacuum around the inlet valve stems). In the diesel, I'd expect it to be less pronounced (no significant vac. in the inlet). That is, unless it's been idling for very long periods and there's a big build-up of unburnt oil in the exhaust, when you may well get light blue smoke until it clears. The 1.8 litre versions, both petrol and diesel have, I think, proper seals on the stems.

It might be worth noting that, after I fitted an old AC air inlet filter/silencer to my 1.5 T90, the engine DID give off light blue smoke when idling (it didn't get beyond idling till I'd rectified it), which cleared once I'd removed the wire wool type filter material. The restricted flow in the inlet was obviously enough to produce a significant vaccum, sucking oil down the stems. The engine is in good condition, using less than a top-up of oil per 100 hours. Bear in mind that in its standard setup, the T90 has NO air filter, NO air silencer, NO inlet restriction, simply a cover with holes small enough to prevent the ingestion of house bricks and seagulls.

The risk presented by excess oil drifting around the inlet ports is that the engine could fuel itself on lube oil and run away to destruction. However, if it's that serious, it would probably be running quite badly with intermittent pre-ignition knocking due to uncontrolled early combustion of the oil.