Morris Minor Owners Club

Primrose has done a new thing today.
Whilst i was on my way home from work, i stopped at a junction and a beetle drew up along side. Now not wanting to be silly, i wasnt going to let Primrose be beaten by some little beetle, so when the lights went green, i buried the throttle into the carpet. after safely seeing the beetle off, i noticed that Primrose has laid down a smokescreen any destroyer or battleship would be proud of.
This coupled with the many jars of mayo that i keep wiping off the filler cap would generally point to the head gasket being on the way out. would i be right or have i simply lost a valve stem oil seal and the mayo is due to the weather?

Semi-knackered engine........and cold weather

the engine is good, save for the smoke screen, new bearings, crank, bearings and piston heads, so its got to be the head gasket. the engine has only done about 2000 miles since its rebuild

If it's making a smoke-screen - it's semi knackered.......... It's not gasket or seals........... A complete rebuild involves rebore and new pistons etc......

humm, well i got the new pistons and rings, the bores where not scored or marked, so i didnt bother

find yourself a compression tester just to be sure.

low compression could be a headgasket gone (especially if two are low as one could be blowing into the other), or a low reading could be poorly seat/burnt out valve, or blow-by in a bore, potentially a broken compression ring can reduce compression.

if you've not rebored your engine there could be a small 'step' at the top of the bore where it doesnt wear. the drag race would probably have meant you were revving higher than normal, which causes extension of the con rods, so the piston goes fractionally further up the bore. this isn't normally a problem but with the 'step' at the top, your new rings could have crashed into that step and suffered some damage.

with your compression test, do it as normal and note the values, and then repeat it with a small squirt of oil down the bore, if the compression is then up as high as the others then the oil has blocked the 'leak' (which due to gravity can only cure anything piston/ring related) and you have proven that the loss in compression is piston/ring related. if it hasn't cured the low compression you're looking at gasket or valve related. do be aware that putting oil in a good bore will increase its compression, so when you do your test, put some oil in a bore that gave a good compression as a benchmark.

you could get a friend to follow you on a short trip and get them to keep an eye on your exhaust for puffs of smoke. quite often a long run down a hill running on the back of the engine, can result in a puff of smoke once you put your foot down again. this can be valve guides or valve stem seals leaking oil, as with the throttle closed the engine will try to draw in air from elsewhere, so the engine draws in a bit of air down the guides if it can, which brings some oil with it. but this doesn't sound like your scenario.

finally, are you sure it was engine smoke? not fog? or tyre smoke? or the beetle catching fire?

I believe the new piston rings will be the problem. If you fit them without honing the bores then they will never bed in.

[quote]/revving higher than normal, which causes extension of the con rods[quote] mmmmmmmmm ,

What colour was the smoke?

a whiteish colour, and when i let it idle in the snow, their was always a big black slodge under the exhaust

I wouldn't worry then, white smoke is just steam which is a by-product of combustion.
Very visible in this weather, but nothing to worry about unless the water level in the rad starts going down.

The black stuff is carbon, another normal by-product of combustion AKA tailpipe emissions.

oh well, was still impressive to see my wipe the floor with a beatle.

Standard minors can be quick to 30. I beat a modded 1275 5speed etc minor..

You said - "a smokescreen any destroyer or battleship would be proud of" - which does not suggest 'water vapour'..... If it's black - then perhaps too rich - what colour are the plugs?

a lovely light grey with no crude or anything attached

Sounds about right!

Hi,
I had very similar symptoms in November 2010:
Huge ploom of white smoke from exhaust (cold weather makes it even more visible! - worse when just started engine, but still there when warm)
Mayonnaisey oil filler cap
Black sloudge under exhaust after idling

Also had oil in the water (lots!)

It was a blown head gasket. Strangely, it didn't get shot of water particularly quickly.

melanddoug wrote: I had very similar symptoms in November 2010:

Actually it was the Moggy, not me.

melanddoug wrote:

melanddoug wrote: I had very similar symptoms in November 2010:

Actually it was the Moggy, not me.

Very lucky so! -sore thing that!

Regards
Declan

At least your con-rods weren't extended...........