Smokey Diesel and WOF

[snotgoblin]

Evening All,

First time diesel owner here. I have a 1980 BJ40 with the original B series 4 cylinder in it. Someone has sneakily thrown a turbo on it too - not sure what size etc or what boost it is running. All I can tell is it is from a Nissan - but it looks kinda tiny.

Anyhow - The black smoke as you "blip" the throttle off idle is not insignificant. (Shiteloads) Can any of you guys give me some pointers on (old) diesels and the smokey exhaust aspect of the WOF inspection?

I have recently replaced the air filter and the glowplugs - not that seemed to make it that much easier to start. It does run pretty smooth once going, but I think it might be overfuelling/running rich as it smells like that?

[keithal]

yeaa black smoke in a diesel is too much fuel

[snotgoblin]

cheers keithal.

doesn't smoke too bad once it stabilises or when accelerating normally. But when it works to get the revs up she blows bad..

[Cameron]

just turn the fuel down before a wof
it's smoking because there's nothing to limit the fuel until it comes on boost, thus dumping a shitload more fuel than there is 'air available'. she clear out once acceleratingnormally as the turbo has spooled and it making boost, thus the air vs fuel ratio is a little more in your favour.

[crazyclark31]

as the man said turn the fuel down. Main reason this needs to be done is if it is to rich then you'll melt the top off your pistons.

[tweake]

is it he B series that run a throttle setup in the intake?

add to the others that its to much fuel. the minor bit of damage done is accumulative so it will eventually crack pistons/head.

[snotgoblin]

Cheers fellas.

Still a bit to learn with diesel donks obviously. Interesting about the melting pistons if too rich concept. Familiar with the basic concepts of turbo charging, but mostly on aero engines.

The richer a petrol motor runs the slightly cooler it runs at.

[tweake]

with petrol the fuel enters on the intake stroke evaporates and cools the pistons. diesel is burnt as its injected so theres little to no time for it to evaporate so no cooling by the fuel. diesel relies on the air to cool the pistons. to little air, ie rich, and the pistons will overheat.

[Timmy511]

wouldnt worry about a bit of black smoke, the challenge boys back home were running landy td5s so they black smoked on tick over never mind under load, most standard diesels are set to be 70% safe and nowhere near the limits of where they could be running.

get an exhaust gas temp guage plummed into your turbo turbine housing and see how hot shes running, its the safest way to tune a diesel, i cant remember the temp figures of whats safe and whats not, the internet will know however.....