Smoke

[mark westbrookwhite]

Oh well that looks like the last run out for me this year, I have smoke coming from the exhaust and can only assume its the rings unless anyone knows of another reason?

[stevejgreen]

Re: Smoke

What colour?
All the time?

https://www.autoguide.com/auto-news/2013/01/what-does-the-smoke-from-my-exhaust-mean.html

[mark westbrookwhite]

Re: Smoke

White / Light gray. Not all the time but getting more frequent particularly if I accelerate hard, sometimes large cloud accompanied by pinking sound.

[lil_red_roadster]

Re: Smoke

Head gasket on the way out would be my guess - what does the coolant smell/look like..? If you can smell fuel in the coolant then HG is the culprit. Just out of interest do you have a servo fitted..? If so there is a possibility that the non return valve has failed and brake fluid could be getting through a faulty MC seal and into the inlet manifold.

[mark westbrookwhite]

Re: Smoke

Ok Guys, There is no unusual smell in the coolant, and no white residue in the oil, but there is Oil/hydraulic fluid in the vacuum pipe from the servo.
The engine bay is covered in oil but this is because some pillock forgot to replace the filler cap when he topped up the oil last week Doh!
so it looks like I need to replace the MC seal? in the servo and take the head off and look at the gasket. Still cheaper than a rebore and rings.
Fingers crossed.

[stevejgreen]

Re: Smoke

Oil can get into the inlet manifold from the engine breather system. Usually very neglected as its fitted behind the exhaust manifold. Its often listed as simply being a crank case cover. If you were doing a head off job, its worth popping the covers off to check as the breather section does retain some oil in its wire 'filter'. Double check the gaskets that are used because despite the manuals, I have found two different sizes, for the front and back cover.

[lil_red_roadster]

Re: Smoke

I'd rebuild the MC first (and clean out/renew the vac pipe) then see if the problem is cured before embarking on a head job. That said, beheading a B is pretty straightforward. Good call on the gaskets Steve...I always wondered why the last time I rebuilt a B Series I struggled to make new seals fit...!

[mark westbrookwhite]

Re: Smoke

OK So the head is off . The inlet manifold is full of oil the head gasket is in tact and I can't see any damage or marks on the pots.
Any Thoughts.

[philcoyle]

Re: Smoke

Crankcase breather blocked, or worn rings and any crankcase pressure is then vented out of the rocker cover into the intake manifold, or valve stem seals rock hard.

[ruby131]

Re: Smoke

Hi Mark, as the oil is only deposited on the inlet side of things my guess would be either brake fluid from the servo system or as Phil suggests crankcase pressure. A good sniff of the residue is a clue, you can normally smell if it is brake fluid. Strange that you dont mention any sign of a misfire with that much oil about I would have expected that at least. Did you check the compressions before you removed the head? This would give you at least an idea if the rings were badly worn. look forward to further updates. Chris

[stevejgreen]

Re: Smoke

Is the front cam cover full of oil? If you were getting some sort of crank case pressurisation oil will get from there into the inlet manifold.
As said before, can you identify which oil it is? Have you been consuming unusual quantities of brake fluid or engine oil? It has o come from somewhere?
Pressurisation is possibly due to piston ring failure, worth a feel of the pistons to see it there is any unusual piston slop. Again shame you didn't get a compression test done, it might have given us a better clue.

[cameronfurnival]

Re: Smoke

iirc the servo can fail and allow brake fluid into the inlet. This will give white smoke at the exhaust and your brake fluid level will drop (how quickly depends on bad the diaphragm has perished) you will also get a hard pedal when braking. Worth a check if all else is ok.

[mark westbrookwhite]

Re: Smoke

It is definatly oil not brake fluid as it doesn't smell like fluid and I am not going through any. The car was definitely harder to start and certainly at first it was misfiring. there is no discernible piston movement, damage or any sign of oil smear on the pots. There is a heavy carbon layer on the top of the pistons and the head which is even over all 4 pots. I stopped at MG Bee hive to pick up a new top gasket set and asked if they had any ideas (Nice helpful guys) there mechanic suggested that the oil breather was the likely cause as per Stevejgreen suggestion.
I have decided to take yours and their advice and try and clean this all out first.
If I can get another 6 weeks of driving pleasure before I take the car off the road for the winter I would rather do this and worry about testing the compression when I don't mind that it will be out of action for a while.

[b_caswell]

Re: Smoke

Hi Mark, Is this a Triumph engine or a BMC ?

[mark westbrookwhite]

Re: Smoke

Hi Ben,

It is an early 70's MGB. and when i striped out the breather it was completely blocked up with gunk so I tried to clean it out but it wasn't having any of it so i striped the one off a spare engine I recently purchaced. this was much easier to clean out. I fitted it and cleaned out all the breather pipes. I took it out for a test drive last night and no smoke!!!!!
So fingers crossed I have the next month of fun then I will take it off the road and check the compression. I am swapping the gearbox this winter and if I have to i will get it a rebore and new rings at the same time.

Thanks for all your help guys much appreciated!!

Mark.