smokey engine

[delboy]

i started my coach up today after been standing for a few months, seemed to be loads of really strong diesely smelling smoke, does anyone know what the problem is?
its always done the same thing ever since i brought it last year, but after a 10 mile run it clears.
i dont want to finish the conversion then smoke out a campsite on leaving day

[Jonathan Smith]

Older engines tend to do this, they like to be run everyday.

If you leave it idling for long periods ie charging the batteries whilst you are working on fitting out, soot gathers in the pipe, when you drive off it can take a while for the soot to be blown out.

If you take it for a good long run that will blow out the system.

Once it warms up it should run clear. What sort of engine is it?

[delboy]

i cant take it for a run as the road behind will be hidden in a diesel fog.
ive tried leaving it running for an hour but still tons of strong diesel smelling smoke, not black but sort of a grey colour.
the engine is a ford 6 litre turbo diesel on a ford R1114 chassis.

[Jonathan Smith]

Yes grey smoke, it will run clear.

Leaving it idling adds to the problem, you need to give it a good run.

If you try it on a windy day the smoke will be dispersed quickly by the wind.

[delboy]

what causes the engine to give off the grey smoke?
can it be cured?
ive read that getting the injectors overhauled is a good idea as they may not be atomising the fuel correctly, what do you think?

[Jonathan Smith]

I've spoken to a few mechanics about this, they basically say, it's how the engine operates at the normal operating temperature that you should be concerned with.

Before the engine gets up to it's operating temperature it will smoke, if it stops smoking after it's warmed through then it's ok.

If you went into a 1979 bus depot at 7am the whole place would be full of thick grey smoke.

Older diesels tend to be smokey on start up and give a little puff when accelerating.

You could get the engine overhauled which would cost about £5K but it is likely it will still smoke on start up.

My bus gives an impressive plume of thick grey smoke in the morning, it's been MOT'd three times and passed the emissions tests. It runs fine when it's warmed up and the engine is under load.

When I got it back after the last MOT it had been in the garage for a while and had not been opened up. So being driven at tick over around the garage the exhaust was full of soot, it took a good mile to clear it.

Ships engines are the same, I was told not to run the main engines at slow speed for long periods, if we were hove too in rough weather with the engines running slow ahead for hours I would have to open up the engine periodically to "blow the tubes", simply run the engine at full power for a couple of minutes to blast the soot out. As the exhuast on a ship runs vertically like a chimney you could have a funnel fire with all the carbon lining the inside of the funnel.

So you get an impressive black plume as the carbon is ejected, usually covering the decks much to the bosuns distaste.

diesels don't like running at tick over

[stevec]

Another solution is to put the exhaust up in the air like on trucks, campsites would be a little cleaner

[Jonathan Smith]

I was thinking about that, proper job

[delboy]

trouble is its that smokey it would cover the whole campsite in a fog.

[jimmy193]

Hiya fellow smokers !!
"George" smoked pretty bad when I got him but soon cleared his tubes on the run up from Birmingham to Edinburgh. I noticed the same problem as you Del so I shoved in a bottle of red-ex for diesel engines when I filled the tank. He still gives a puff of the grey stuff on start up but runs clean as a whistle after that. Our forklift mechanic (time served coach mechanic) offered to give the injectors the once over when he has time, he said it may improve the performance a bit but wont change the smoking.
Maybe we could get the exhaust up through the floor and out the roof with a heat exchanger in the middle - solve 2 problems in one go!!
Regards.

[delboy]

ill give the redex a go and see if it helps.
i dont want to get knicked by the old bill for creating excesive smoke and polluting the atmosphere, especially before i get to the MOT station.

[jimmy193]

If it still smokes the old bill wont be able to see you for the smoke.
When are you in for MOT then ?

[duple425]

Try a mix of 4.5 liters petrol to 100 liters diesel, this will clean your injectors out and de-coke the engine. Won't stop the grey smoke on start up till the engine gets to running temp, but will help reduce it. Best way to drive a bus is start and go, they don't like to sit on idle for periods.