Smoking! Advice please.

[MaestroMatt]

Now I am starting to get annoyed with the ingratitude of A82 WHR. I spent the whole of Saturday - with F153 and A251's help - replacing the front driveshafts, front brakes, and front and rear suspension (pics to follow soon!) and instead of thanking me for cherishing her, A82 started belching out smoke from the exhaust like never before.

I need ideas on what this might be so here are the symptoms.

- R series engine with 47k on the clock. 20 years old.
- Sump oil level is right at the max mark and doesn't appear to be dropping.
- Coolant is still bright green and doesn't appear to be dropping
- I filled the oil in the dashpot and it is mostly gone already.
- Compression test showed 14.2 bar on 1, 2 and 4 but 13.5 bar on 3.
- Smoke seems oily - smells exhausty with distinct overtones of oil.
- Is worst when revved but seems intermittant. Sometimes it looks/smells like only exhaust is coming out.

Now, it did seem better this morning - far, far less smoke than yesterday and I know that from the above, the carb looks to be most at fault - if I had over-filled the dashpot, could it have got into the fuel? Could I have overfilled the sump oil level and now I have repaired the cam-cover oil leak, it is finding an outlet into the fuel system? Do I have anything to worry about with the 0.7 bar difference in compression in cylinder 3?

I really really really can't be bothered to replace the head gasket but I am prepared for the worst so tell me what you think!

[Mat_C]

Were any of the sparks oil-fouled? Does the soot in the exhaust feel oily?

[MaestroMatt]

To be honest, all of the sparks looked a bit damp and oily! Now I think about it, that does suggest a problem in the fuel system - distributing oil through all four cylinders and making it smoke like a two-stroke engine!

[Mat_C]

It could also be your valve stem oil seals - do you get a good puff when you drop it down a gear going up a hill for example?

Age instead of wear might have got at them.

[MaestroMatt]

Yeah a good puff of smoke when I drop down a gear and when I pull away. Tends to be better when cruising.

Are they an easy job?

[G Force]

Hi, I think your compression readings are fine I would not worry about No. 3. You could have problems as suggested above, I think that if your engine is smoking but you are not losing any oil you should check to see if the oil is contaminated with petrol. Sometimes the lift pump can leak petrol into the engine, causing the oil to dilute.

Regards Gary

[E_T_V]

The valve stem seals are easy to replace but will most likely need to have the engine head removed to do so (so also curing your worries about your head gasket which seems fine to me from the figures)

I've never worked on an R series but the S and A series are pretty straight forward to do. The hardest bit is usually removing the exhaust manifold again fixing another problem you have!

The oil smoke may well be from an overfilled dash pot which would certainly dump oil into the inlet manifold, or even an overfilled sump. Take it for a good long run and see what it is like then before condeming anything.
Also smell the dipstick to make sure it doesn't smell of petrol. If it does your fuel pump may well be knackered and dumping fuel into your sump.

[MaestroMatt]

Thanks for all the advice - I tend to do only two jouneys of 8 miles a day which doesn't help clear the system of anything. I will take it for a good run at the weekend and get it nice and hot and see if that burns off the last of whatever it is. If it still remains I will start to check for suspect parts. I am fitting a new fuel pump at the weekend anyway as I have my doubts about mine - if it isn't failing now, it will soon!

[MaestroMatt]

Hmm, more smoke this morning - and just as I thought it was stopping. Definitely a blue hue to it so oil and not coolant. Where could the oil be getting into the fuel?

Had a thought though, there is a breather pipe on the top of the cam shaft cover that goes down to the bottom of the carb. I had assumed that this was to burn off any oil vapour that was expelled due to high pressure. Have I got this right? Then, if the oil is getting too pressurised (due to another part of the oil breather system failing, perhaps) could too much oil be going down this pipe into the carb?

[E_T_V]

Possibly. unplug it and see :D

Does it smoke consistantly or only on startup? do you park on a slope by any chance? If so try parking the other way round and see if the problem is still as bad. Pointing in certain directions when parked leaves pools of oil sat above valve stem seals which then let it leak into the cylinders giving great clouds of smoke on startup. If it isn't using any significant amount of oil I'd not worry.

[G Force]

Hi, if you haven't changed the oil for a while it might be useful to change it, you can get dilution of the oil if you just do short journeys or if the engine is running too rich.

The breather pipe on the cam cover to the bottom of the carb is there to stop the crankcase from pressurising as you say. You could get oil going down this pipe if the engine was badly worn or the oil filler cap was blocked as it is the oil filler cap on the r series that allows fresh air into the crankcase. If the oil level is too high this can cause the engine to smoke due to the crankshaft throwing oil up the bores, and also oil pull over on overrun.

If you have changed the fuel pump, changed the oil and checked out the breather system and you find that the engine still smokes then I think the favourite suspect is going to be worn valve stem oil seals and or valve guides.

Regards Gary

[MaestroMatt]

Right, latest installment - your views please, even if you are more than bored of trying to work out why my previously well behaved R series is smoking with the enthusiasm of (the late great) Bill Hicks.

Firstly, the sump oil level has dropped considerably which isn't really surprising. I have also realised that the smoke only occurs when the engine is hot and I rev it, so when I got home tonight, I did some detective work. I changed the cam shaft cover on Saturday - which is when all this trouble started - which stopped oil escaping from round the gasket so I think that this problem must be an oil pressure one. I took the breather hose off the cam shaft cover and sure enough, a very large quantity of oil vapour and flecks of oil were gushing out of the hole. Why is the oil pressure so high? I took off the breather mushroom from the crank case (it is located just near the gearbox) and noticed that it was completely uncontaminated with oil (it was replaced as a service item a few months back). Therefore the breather hole must have been blocked. I got a length of rubber hose, clamped it over the breather and blew down it until air moved freely through the system. I think a blockage was removed. It remains to be seen whether the problem is now cured but rest assured that I will let you know!

Opinions very welcome!

[MaestroMatt]

Damn it! she is still smoking this morning.

Could it be as simple as the fact that the mesh inside the cam cover below the breather pipe has deteriorated with age (there is certainly far less than in my other cam cover) and is not doing its job in stopping flecks of oil being forced down the breather pipe? As I mentioned, when you pull that pipe off the top of the cam cover, a lot of oil comes out with the vapour.

[G Force]

Hi there. Sounds like you have probably hit the nail on the head. If the cam cover you have fitted does not have the gauze or the baffle then the camshaft will just flick oil straight up the breather pipe.

What was wrong with the old cam cover? Can you not put it back on or take the gauze and baffle out of it.

Regards Gary

[MaestroMatt]

The old one was cracked. I had repaired it with leak-fix and that had stopped the oil from spurting out of the top but couldn't torque it down quite enough onto the shoddy cork gasket I had for fear of cracking it again. Now I have found an aspestos gasket, I may be able to use the old one again. I'll swap it over as soon as possible and see if the problem stops. Not sure the gauze and baffle are removable - does anyone know?