Volvo MD2020 - Head removal advice needed

[Jokani]

My Volvo MD2020 will not rev for 30 seconds after starting, and has white smoke or steam in the exhaust , except for when warm with a few revs on.

I have eliminated the following possible causes:

1) Air in the fuel (fitted clear pipe)

2) Fuel injection issue (professionally spill tested)

3) Cam shaft/timing gear (Cover removed and verified timing correct)

4) New Johnson raw water pump (100 hours so no/very litle wear)

The engineer that conducted the spill test could not find a problem with the fuel injection system, but said that the compression seemed extremely high and that combined with the smoke made him think that the cam shaft/ timing gear could be one tooth out. Last weekend I removed the timing gear case, and unfortunately it was correct, which still leaves me with the problem, plus I found emulsified oil and water in the timing gear case, injection pump housing and oil filler, but not in the dip stick which I had been checking.

Next step, this weekend, remove the head to check that and see what I find.

I can't afford to have the work completed professionally, so the task falls to me this weekend, but I have never removed a head before.

Looking through the Volvo workshop manual it seems a relatively simple process, but I thought it would be wise to see seek any general tips on head removal here, or maybe I could be lucky and someone here has experience of removing an MD20x0 head?

Thanks in advance.

 

[RichardS]

In 50 years working on engines, I have never heard anyone suggest that a valve timing error could cause increased compression.

Before you start major work, have you checked that the exhaust elbow is not blocked? Your problem does sound more serious, although the limited emulsification could be just localised condensation, but it's worth exploring the simple issues first.

Richard

 

[SAWDOC]

this series of videos describes the rebuilding of a MD2010

 

[Plum]

My Volvo MD2020 will not rev for 30 seconds after .

So are you saying that after the 30 seconds it will rev and then runs ok?

Www.solocoastalsailing.co.uk

 

[Jokani]

So are you saying that after the 30 seconds it will rev and then runs ok?

Yep, it stuggles to start, sometimes stops, then when it does get going it will not rev for upr to 30 seconds. Lots of white smoke at low revs even when the engine is warm, lots of revs and then the smoke disappears.

 

[NorthUp]

sounds like a glowplug issue.

 

[PaulRainbow]

sounds like a glowplug issue.

Yes, definitely a glowplug. Failed glowplugs always cause poor starting, white smoke/steam from the exhaust, raised compression and water in the oil. :encouragement:

 

[PaulRainbow]

In 50 years working on engines, I have never heard anyone suggest that a valve timing error could cause increased compression.

Before you start major work, have you checked that the exhaust elbow is not blocked? Your problem does sound more serious, although the limited emulsification could be just localised condensation, but it's worth exploring the simple issues first.

Richard

A little more detail for you Richard.

Garys engine has a chequered history, it has already been rebuilt once, not so long ago. It was running OK, but now has the following symptoms :

Poor starting from cold.
Will not rev above low idle for several seconds.
White smoke/steam from the exhaust.
According to the guys that did the fuel tests, excessively high compression.
A greater diesel knock than previously.
Emulsified oil/water in parts of the engine.

I've already expressed my opinion, based on the above.

 

[VicS]

So are you saying that after the 30 seconds it will rev and then runs ok?

Www.solocoastalsailing.co.uk

Yep, it stuggles to start, sometimes stops, then when it does get going it will not rev for upr to 30 seconds. Lots of white smoke at low revs even when the engine is warm, lots of revs and then the smoke disappears.

sounds like a glowplug issue.

Yes, definitely a glowplug. Failed glowplugs always cause poor starting, white smoke/steam from the exhaust, raised compression and water in the oil. :encouragement:

If it eventually runs Ok once it has warmed up a little then I agree with Northup and Paul rainbow
I'd guess if one has failed it would be difficult to start from cold. If two have failed very difficult. If all three have failed next to impossible.

Check that there is power to the glowplugs during the preheating and cranking stages

If power is getting to them Ok check them individually. I would normally do this with a car headlamp bulb from battery positive after disconnecting them

BUT BUT BUT remembering the some of the past history I'd also want to check the earthing. I dont remember if your engine is one of the early versions with an isolated negative or not. If the block is connected to battery neg no problem but if it is via an earthing relay then theres a bit more to look into.

 

[Bobc]

I have seen similar symptoms before.

Once on a car, where the PCV valve was stuck open, so was pulling oil vapour up from the sump.

Once on a boat engine, where the valve stem seals had gone, pulling oil into the cylinders on startup.

My advice would be:-

First check the glowplugs.
Next, if you have a PCV valve, replace it.
Next, if it still persists, head off, new valve seals and head gasket.

 

[PaulRainbow]

If it eventually runs Ok once it has warmed up a little then I agree with Northup
I'd guess if one has failed it would be difficult to start from cold. If two have failed very difficult. If all three have failed next to impossible.

Check that there is power to the glowplugs during the preheating and cranking stages

If power is getting to them Ok check them individually. I would normally do this with a car headlamp bulb from battery positive after disconnecting them

BUT BUT BUT remembering the some of the past history I'd also want to check the earthing. I dont remember if your engine is one of the early versions with an isolated negative or not. If the block is connected to battery neg no problem but if it is via an earthing relay then theres a bit more to look into.

Really ?

This place gets more and more bizarre by the day.

Poor starting from cold.
Will not rev above low idle for several seconds.
White smoke/steam from the exhaust.
According to the guys that did the fuel tests, excessively high compression.
A greater diesel knock than previously.
Emulsified oil/water in parts of the engine.

And you think that's caused by a glowplug ?

 

[PaulRainbow]

I have seen similar symptoms before.

Once on a car, where the PCV valve was stuck open, so was pulling oil vapour up from the sump.

Once on a boat engine, where the valve stem seals had gone, pulling oil into the cylinders on startup.

My advice would be:-

First check the glowplugs.
Next, if you have a PCV valve, replace it.
Next, if it still persists, head off, new valve seals and head gasket.

Valve seal failure causes blue smoke Bob. Besides, the engine was rebuilt last year, including new stem seals.

 

[Heckler]

Valve seal failure causes blue smoke Bob. Besides, the engine was rebuilt last year, including new stem seals.

Given its past history and the rebuild, then a few months ago a "failed" lift pump, could it be bug in the tank causing blockages from the tank to the engine? Dont forget, this is an elderly Westerly with an elderly fuel tank?

 

[Bobc]

Valve seal failure causes blue smoke Bob. Besides, the engine was rebuilt last year, including new stem seals.

Grey smoke

 

[peteK]

Water in the fuel will give poor starting .diesel knock and possibly steam in the exhaust.

 

[Bobc]

If it runs lumpy and won't rev when first started, this would suggest that some (or indeed all) of the cylinders aren't combusting properly. This could be due to 1)low compression (but you've ruled that out), 2)bad injectors putting big globules in rather than a fine spray (but you've ruled that out, 3)glow plugs failing, 4)oil and/or water in the cylinders stopping the vapour from combusting properly.

The smoke you see is probably mainly unburnt diesel due to the lack of combustion.

If all gets better once the engine has warmed up a bit, then it is either something that is happening while the engine is stopped (oil and/or water running into a cylinder or two) and something that is such a small leak that it gets vapourised once the engine is warm.

If you do take the head off, do it once the engine has sat for a day or two, and then look in the pots to see if you can see any oil or moisture residue.

 

[Jokani]

Water in the fuel will give poor starting .diesel knock and possibly steam in the exhaust.

Fitted a new plastic tank with a Racor500 filter and water seperator - Pretty sure that I can exclude water in the fuel.

this series of videos describes the rebuilding of a MD2010

Ta for the video, I did have that stored away, but had forgotten about it. I'll watch them again it will help.

I'll take the head of this weekend and report back.

 

[Bobc]

Another quick thought. Have you checked the crankcase breather circuit?

When you first start an engine, there is negative crankcase pressure (there is suction into the head). This goes positive once the engine gets going.

Probably not, but a thought none-the-less.

 

[PaulRainbow]

Grey smoke

Plenty of references to the different colours of smoke on the net. Garys engine is a Volvo badged Perkins. Perkins seem to agree with it being blue https://www.perkins.com/en_GB/resources/useful-information/blue-smoke.html

It can sometimes look a little grey, but whatever it might look like, it doesn't look anything like white.

 

[Bobc]

Plenty of references to the different colours of smoke on the net. Garys engine is a Volvo badged Perkins. Perkins seem to agree with it being blue https://www.perkins.com/en_GB/resources/useful-information/blue-smoke.html

It can sometimes look a little grey, but whatever it might look like, it doesn't look anything like white.

Agree, but I reckon the white smoke he's seeing is mainly un-burnt diesel due to poor combustion (maybe with a bit of oil smoke mixed in).