Morris Minor Owners Club

Just started the engine today and my engine seems to be billowing smoke from the rocker cover, when you take the filler cap off its like i have a second exhaust. Any ideas what might be causing this? everythings seems to run fine except the smoke!!!!

Bad news?

Sorry,
If the engine has been standing for some time it may "just" be water vapour as the whole thing dries out...
If you're unlucky, it could be that the sump is being pressurised - bad rings, of perhaps valve guides. That's not a happy thought.

All the best,

Colin

the engine is a new 1380 MED engine, it has only done approx 500miles. It has been sat for approximately a yr waiting to be fitted since its initial 500 miles. So could this just be water vapour?

No - there is something seriously wrong with it !! Are the breathers clear ? Does it HAVE any breathers ? There should be breathers on one of the tappet chest covers, on the rocker cover itself and possibly (good idea for a modified engine) also on the timing chain cover. One breather - usually the one on the rocker cover - should be connected to a carburretor to create a slight suction effect - but this can only deal with normal slight blow - by - not plumes of smoke !! have you asked MED ?? What do they say ! Was it a MED Kit - or a complete engine ?? I have to say - it's not the first time I have heard of problems with MED engines.

Ok, an update. It would seem i probably have a blocked oil way. Would an engine flush and change of oil cure this or is there something major i need to tackle?(Daunting!!) The engine smoke it would seem is coming from the bottom of the engine not valves etc It pours out of the (Not sure what it is called)"Flame trap" if that is the small bottle shaped thing on the front of the timing chest. Where should this be plumbed too? on my other minor it is connected to a breather on the carb is this correct? Would you guys agree with me that it is probably a blocked oil way?
Thanks
Martyn

Hello Martyn,
a difficult problem, but if it was a blocked oil way I don't believe it would cause smoke and would also cause engine damage, the extent would be due to where the blockage is.
Is your coolant level remaining constant?
Is the smoke at a high pressure?
Does the smoke start as soon as you run the engine?

Alec

Would you guys agree with me that it is probably a blocked oil way?

no

It is probably combustion gasses getting past the rings - or even possibly the head gasket. You need to look at a few more things (as per questions already posted) but it is unlikely there is much you can do without some engine dissassembly.

would i be able to test for the rings by a compression test? oil pressure is at 80psi would i be getting this if the head gasket had gone?
Thanks
Martyn

ps, yes it smokes at start up. If i remove the breather pipe from the timing cover smoke pours out just turning the engine over!!!!

ok this is the thing, i have not had a chance to drive the car only start it for a maximuim of a couple of minutes at a time. The car has no lights etc so i cannot road test it, i didnt want to drive it with this problem if it was going to exasperate the condition. Do you feel driving it for a bit might sort the smoke problem out? the breather is connected to the carb and not the air filter, i also have a breathable cap as an inlet. I will do a pressure test tomorrow and see what i come up with.

You say that it has only done 500 miles. Did it smoke during those
early miles? Your timing cover breather should be piped to the
CARB (not the air filter).

Hello Martyn,

a compression test may give some indication and the oil pressure is rarely ever related to head gasket failure. From your last post I take it that even before it fires smoke appears?
I think you originally said that the engine runs well?, and with little or no exhaust smoke? have you done an oil change since the engine was installed, certainly it is advisable with a fresh engine. If not I think that would be my next step. Look closely at the drained oil, note any smells which may give a clue as to the source of the smoke. You need to have a liquid to give a vapour, (smoke plumes on display aircraft is done by injecting diesel into the exhaust for example), it may be combustion gas or some contamination.

Alec

I have done a compression test, 3 of the cylinders have 150-160psi but no1 cylinder has only 60psi. I poured a teaspoon of oil into the cylinder and the pressure rose to 80psi. Does this point to dead rings? if so is it a job i can do with the engine in situ? what would it involve?
Thanks
Martyn

ok,
removed the head and also dropped the sump. All the valves seem fine, not even the slightest build up of carbon and no marks anywhere they also seem to seat fine which is good. Pulled the pistons out and there is a different story. No1 piston has broken up around the ring area, both of the rings were in pieces. One of the rings on cylinder 4 had also broken. Any ideas why this would have happened on such a newly built engine? Is it considered ok to change just the broken piston or should i change all four? Does anyone have a clue how i remove the gudgeon pin from the piston, i know on the standard cars they have a clamp screw but my pistons do not have this. (Maybe just a drift and a hammer?)
Cheers
Martyn

Hello Martyn,
it is OK to replace only the damaged piston; why it has occurred is a different matter. Especially as No. 4 has a broken ring also. The only thing that comes to mind is that the rings weren't gapped. Rings need a small clearance between their ends when fitted into the bore. I would certainly talk to the engine supplier.
The gudgeon pins should push out with some heat on the pistons or else carefully drift them out.

Alec

The pistons have the following markings AE21251 +060 KZN Any idea where i can get these, next day delivery would be good.

Only people I can think of that at the moment are morspeed. They mainly do mini stuff but you can always ask if they do them if not I'm sure they know who does. Try calling them on 01530 830369 or there sire is http://www.morspeed.co.uk/

Lee

or MED Engineering: http://www.med-engineering.co.uk/

Be VERY careful about removing the gudgeon pins as they don't like coming out and even with heat you can damage the pistons VERY easily. Best bet is to take your new pistons and your old ones (still on the rods) to an engine building engineering company and get them to use their press to take the old ones out and fit the new ones.

Check your bores are not scratched or scored either by the broken rings. The will probably be OK, but it's best to check.

Bit worrying that this has happened. The only reason I can think of is faulty/unsuitable/incorrectly gapped rings. Very strange though. I would definately speak to the engine builder.

If you leave the 3 undamaged pistons in place then the minimum you need to do is replace the rings on all the other pistons.
It may well have been bad handling that damaged the rings in the first place so it is a big risk to leave the other rings in place

what is the correct procedure for fitting the rings? should the gaps be at 120 degrees to each other?
thanks
Martyn