Morris Minor Owners Club

just started the moggy and went to work and back today. fairly simple and normal occurrence. however, the car was running very very rough. felt like it was running on two or three cylinders and it was vibrating very heavily under running conditions and acceleration. it also wouldn't accelerate very well at all, could reach about 35 and not progress much more. their is quite a bit of mayo around the oil filler cap and i have put this down to the lovely weather.

initially i thought it was something sticking, but after inspection, all is moving well. i also thought it could be a loose or broken cable, but after inspection of them, dizzy and spark plugs, all was found well.
all i can think of is that the piston rings have eventually gone or a bearing is in the process of breaking up.

Luckily, i have another engine waiting to be rebuilt and i was hoping to put it off till the weather was a tad warmer.

so, today's question is:

rebuild due or could it be something else i haven't thought of

Generally an engine due for rebuild has been getting slowly but surely worse over a period of time. If you have checked all the obvious things (electrics/ fuel system) then do a compression test before you start to tear the thing to bits. Post the results and Roy will gaze into his crysral ball and give you some ideas.

I had a similar problem, turned out that the points gap had closed, also the HT leads were past there best.

did a compression test a couple months ago and knew then that a rebuild was on the cards, just didn't expect it to be required quite as soon.
ill check the points and give them a clean with a small file.

As Bill says, engines don't tend to suddenly need a rebuild like that! I, too would check the points gap- sounds the most likely cause of sudden bad running, unless it has oiled/ fouled a plug up, which is a possible offshoot of the worn engine syndrome.

checked the points and all is ok, not stuck together or change in gap.

No matter how recently you did a compression test, do another one now! It could be a valve (or two), a head gasket (common between 3 & 4, so you lose both). At least with some recent readings we'll know where ot start looking - it could be ignition, but you could spend ages swapping different components to isolate, and then still find that it's mechanical. Hope is isn't anything too serious.

Was it smoking badly -is there much smoke coming from the oil filler cap ? Could well be something simple - oiled up plug/burned valve/valve gap closed up etc as others have pointed out. But again - it could be head gasket. Comp test will tell (nearly) all!

right, checked the pressure and we have, 150, 130, 150 and 120. new gasket fitted 7 weeks ago, so "in theory" shouldnt be that. also reground in the valves at the same time.

checked the point, rotor arm and dizzy (all with the aid of daylight) and found to be all ok.

had the rocker cover off and none of the valves where sticking

the exhaust manifold has yet again skightly come adrift from the exhaust pipe, but no where near as had as it has been in the past.

the radiaitor is holding its water their is a nice blue haze behind me where ever i go.

so, i think that one of the piston rings has eventually given up the ghost, hence its running on 3 cylinders.

any other ideas what it could be?

You need to inspect the spark plugs - one may be oiled up. Obviously blue haze is not good............

number 3 plug was very very oily and claggy

Just try a good plug in there - the compressions while not 'good' - don't indicate anything desperately wrong.