BMC smoke issue Question

[denboy]

One for the bmc owners friends newish rebuilt bmc has just started smoking me thinks the fuel pump has slipped as there is a bit of what i think is diesel coming out the exhaust(raw water cooled)question is which way to adjust the pump up or down or is it a case of suck it and see

[Naughty Cal]

What colour is the smoke?

[RLWP]

One for the bmc owners friends newish rebuilt bmc has just started smoking me thinks the fuel pump has slipped as there is a bit of what i think is diesel coming out the exhaust(raw water cooled)question is which way to adjust the pump up or down or is it a case of suck it and see

 

Before you start messing with the pump...

 

Is the air filter clean? What colour is the smoke? Is what is coming out of the exhaust really diesel or is it oil or condensate?

 

Richard

 

This thing about "slipping pumps", is it true or an urban myth?

[denboy]

no air filter fitted white smoke tinge of blue 99% sure its diesel smells like it was running fine 2 days ago so its only just started doing it

[Naughty Cal]

Blue smoke is normally engine oil being burned, white smoke is normally steam, black smoke unburnt diesel

[RobinJ]

no air filter fitted white smoke tinge of blue 99% sure its diesel smells like it was running fine 2 days ago so its only just started doing it

The white indicates fuel, the blue diesel, could it be just the valves not closing fully?

Is it continuous or puffy, how is the engine running smooth or rough?

How about checking the valve clearances or a compression test?

Has the oil level changed, up or down?

Is it a recent recon, when where the filters last changed, injectors serviced?

[Naughty Cal]

Blue smoke is definately burnt engine oil. If it only smoke on fire up it will be worn oil seals allowing oil to dribble past when the engine is sat overnight. This results in blue smoke on fire up that quickly clears when the engine is warmed up. IF you see blue smoke constantly when running you probably have a problem with your piston rings, or maybe the cylinders – or maybe both! Buy yourself a can of ‘oil treatment’ such as Wynns. This may free up the cylinder rings if left overnight

 

Black smoke is unburnt fuel. Most diesel engines emit a little bit of black smoke when acceleratingl. It takes a little time for the engine system to develop the RPM and necessary power to use/burn all the fuel that is being fed to it!

 

There are a number of things that can cause white smoke – if it persists after the engine has warmed up. It can be as a result of a faulty injector, timing problems (normal cause), low engine compression, and/or a faulty fuel pump. Air in the fuel system can also cause this problem. This is a rarity, but not impossible.

 

Lastly steam caused by a head gasket or other water leak into the combustion system can disguise itself as smoke. Steam will dissipate rapidly being once it hits lower temperature ambient air while smoke will persist and hang in the air.

[Albion]

Blue smoke is normally engine oil being burned, white smoke is normally steam, black smoke unburnt diesel

 

Err, no, not quite:

Blue smoke; normally oil but can sometimes be confused by an untrained eye with mixtures of other smokes.

White smoke is most usually incomplete combustion (incorrect valve clearances, low compression, poor injector spray pattern, incorrect injection pump timing etc) and can occasionally be slight coolant ingestion into the combustion chamber but this will generally only be on start up. If you imagine the compression/combustion pressures that exist in a combustion chamber there is little chance of coolant forcing its way in against those sorts of pressures while running. You are much more likely to see gas in the coolant system.

Black smoke is excess fuel to air ratio. This can be down to blocked air filter, overfuelling (pump probs), overloaded engine causing very high fuelling.

Roger

[denboy]

The white indicates fuel, the blue diesel, could it be just the valves not closing fully?

Is it continuous or puffy, how is the engine running smooth or rough?

How about checking the valve clearances or a compression test?

Has the oil level changed, up or down?

Is it a recent recon, when where the filters last changed, injectors serviced?

thought it may be a sticky exhaust valve

continuous engine running fine oil level fine

recon a year ago

[Albion]

One for the bmc owners friends newish rebuilt bmc has just started smoking me thinks the fuel pump has slipped as there is a bit of what i think is diesel coming out the exhaust(raw water cooled)question is which way to adjust the pump up or down or is it a case of suck it and see

 

What bmc is it?

How long since the rebuild?

Can you confirm that it is rawish diesel in the exhaust by teh smell of it>

Roger

[Yoda]

I would go for a dribbling injector or head gasket. Run at high rpm for a while to see if it stops doing it.

[denboy]

What bmc is it?

How long since the rebuild?

Can you confirm that it is rawish diesel in the exhaust by teh smell of it>

Roger

pretty sure its diesel not a lot just enough to see it on the water surface,fairly certain its unburnt fuel when the rain subsides i`ll ask what size it is ,not sure if the rivers above me or below me at the min

1800

Edited July 30, 2009 by denboy

[Mick_B]

One for the bmc owners friends newish rebuilt bmc has just started smoking me thinks the fuel pump has slipped as there is a bit of what i think is diesel coming out the exhaust(raw water cooled)question is which way to adjust the pump up or down or is it a case of suck it and see

Hi Den

 

As it's raw water cooled I suggest you check the weed filter. If you have a blockage the reduced water going through the exhaust will not cool the gasses and evaperate thus showing as steam (white smoke) exiting the exhaust.

 

I had this problem with my BMC 1.5. I changed the impellor when I got it and accounted for all the pieces. Still she insisted on overheating. I then found half of the fins of a previous impellor had been pushed back through the intake side of the pump and stuck in an elbow on the side of the pump.

 

edit to add... This could also lead to the rubber section of the exhaust de-laminating causing a blockage in the exhaust when you rev the engine.

Edited July 30, 2009 by Shinner

[denboy]

Hi Den

 

As it's raw water cooled I suggest you check the weed filter. If you have a blockage the reduced water going through the exhaust will not cool the gasses and evaperate thus showing as steam (white smoke) exiting the exhaust.

 

I had this problem with my BMC 1.5. I changed the impellor when I got it and accounted for all the pieces. Still she insisted on overheating. I then found half of the fins of a previous impellor had been pushed back through the intake side of the pump and stuck in an elbow on the side of the pump.

 

edit to add... This could also lead to the rubber section of the exhaust de-laminating causing a blockage in the exhaust when you rev the engine.

spanners out then

[Albion]

pretty sure its diesel not a lot just enough to see it on the water surface,fairly certain its unburnt fuel when the rain subsides i`ll ask what size it is ,not sure if the rivers above me or below me at the min

1800

 

If it is diesel or oil you will get similar observations if droplets hit the water. You should see a rainbow effect with either. One may seem to have a slightly thinner film when it first hits the water and hti smight indicate diesel. Best indication is smell though.

The 1800 pump is easy to see whether it has slipped because there is a line marked on one of the three lugs that secure it to the front plate studs. There should be a corresponding mark alongside it on the plate IIRC. This might not be a precise science though, as the engine has been rebuilt and someone may have just set it by feel. You need a specialist tool to re-mark the timing mark to align the pump. I made my own marks from first principles on the timing chain cover using a dial test indicator on the top of No 1 piston when I was completely rebuilding and marinising my 1800 for my first boat. Then I was able to set the pump timing from observing the fuel injection cut off point in some tube. The pump retaining nut behind the pump is a pig to get at and I had to make a special conversion of a spanner, bending it and grinding it to get behind the pump and, even then, the range of spanner movement was very restricted. There is also a small torsion bar springy thing that has to be fitted into the end of the pump drive shaft to also engage with the centre of the drive sprocket splines. It's a bit awkward to get this to engage but it is there for a purpose (to take out any backlash in the splined connection, I think).

Roger

[nb Innisfree]

Err, no, not quite:

Blue smoke; normally oil but can sometimes be confused by an untrained eye with mixtures of other smokes.

White smoke is most usually incomplete combustion (incorrect valve clearances, low compression, poor injector spray pattern, incorrect injection pump timing etc) and can occasionally be slight coolant ingestion into the combustion chamber but this will generally only be on start up. If you imagine the compression/combustion pressures that exist in a combustion chamber there is little chance of coolant forcing its way in against those sorts of pressures while running. You are much more likely to see gas in the coolant system.

Black smoke is excess fuel to air ratio. This can be down to blocked air filter, overfuelling (pump probs), overloaded engine causing very high fuelling.

Roger

 

A few years ago I ran an Audi Turbodiesel, after it developed a fuel leak from fuel pump it would drain off overnight and next day it would splutter and chuck out loads of blue smoke until fuel purged any air out when it ran cleanly. So weak mixture = blue smoke? weird

Edited July 30, 2009 by nb Innisfree

[Albion]

A few years ago I ran an Audi Turbodiesel, after it developed a fuel leak from fuel pump it would drain off overnight and next day it would splutter and chuck out loads of blue smoke until fuel purged any air out when it ran cleanly. So weak mixture = blue smoke? weird

 

Did the smoke disappear after you had the faulty fuel pump fixed? If it didn't I can think of a scenario where some oil that had seeped from the turbo seals was being burnt off first thing. Just a thought.

Roger

[nb Innisfree]

Did the smoke disappear after you had the faulty fuel pump fixed? If it didn't I can think of a scenario where some oil that had seeped from the turbo seals was being burnt off first thing. Just a thought.

Roger

 

I passed it on to someone else and yes I recall him saying he had repaired pump and all was ok

[Malarky]

Try turning the revs down to see if it still runs steady, If the speed fluctuates up and down, it's probably the pump timing. You turn the pump to just past where you want it and then twitch it very slightly against the rotation of the chain to take up any slack. As allready mentioned, there should be marks on it to line up.

[RobinJ]

pretty sure its diesel not a lot just enough to see it on the water surface,fairly certain its unburnt fuel when the rain subsides i`ll ask what size it is ,not sure if the rivers above me or below me at the min

1800

Might be difficult to find anyone who can do a compression test, but how about this for ideas?

Check the valve clearances (just to make sure they haven't closed up - other possibility is sticking cam follower) then turn it over by hand and see if there are any valves leaking on compression (you ought to be able to hear them - less hiss)! It is possible a valve has cracked or a bit of deposit has upset the seat?

If there is a sticking cam follower you might be able to hear it drop as you turn it over (usually a plop), or if its staying up, pushing hard on the end of the rocker arms (pushrod end) may force it down?

 

Has the engine been running fine after the recon up until recently?

If it has had the timing chain off, it is possible (1800's can be a b!*!$r to get the chain tight and aligned) that there is a slight misalignment of the camshaft (this can result in retarding the injector pump as the slack is taken up), but only go down this route if it has done this since the recon and the timing chain was taken off!

 

The marks on the injector pump should be half way between the top two securing bolts and there should be a pointer thing on the front plate just underneath the alternator.

[Mick_B]

How'd ye get on den?