Morris Minor Owners Club

Just doing the tappets today, but when I removed the rocker cover I was a bit surprised...
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I knew there was a bit of mayonaise under there because it was on the oil filler cap, but does this amount mean the head gasket is shot, or is it just because the car does short journeys? The car is running fine and doesn't seem to be down on power, but is using quite a bit of coolant. There doesn't seem to be much oil in the water either, but the (1000 mile-old) oil looks a bit grey and sludgy.

Sounds rather gaskety to me

On the bright side it's not much more than an hours work to fit a new one, if everything goes perfectly (so it'll be more like a couple of day then...) and they're dirt cheap

Gasket..Yes and with that amount of mayonnaise you would be well advised
to thoroughly flush out the engine with flushing oil once it is all back together.

If it's loosing significant coolant it may be the gasket, check the compressions if you can. that will be pretty diagnostic.

A crude check is also to run the engine with rad cap off. The water will move because of the water pump, but if it blows bubbles that's pretty diagnostic of a failed gasket.

This is quite normal if you only do short journeys.

Change the head gasket if you want a lot of work but I bet that it doesn't make any difference.

Yes would agree - doesn't look to bad if you are only doing short runs.

Head gasket failure 'usually' results in:
Steam out of the exhaust all the time not just in the morning.
Water in the oil which = white oil, very simple to spot and very difficult to miss!
Water consumption - check the rad!

Steve

Fit a higher temperature thermostat (88 or even 92) - and clear out the engine breathers - and change the oil !

OK I'll see if there are any bubbles in the coolant and see if I can run a compression test on it. When the engine is warm there is no smoke or steam coming out of the exhaust at all - but when cold and there's loads of steam.

I have just thought of another reason why the coolant is being lost - when I changed the water pump I forgot to order a new bypass hose so I reused the old one - not a clever idea I know. At the moment it seems to be losing just over a pint of water every 2 weeks.

clear out the engine breathers

This is an interesting one. I changed the carb a little while back as it was worn. The old carb had an inlet on the bulkhead side of it for the engine breather (which comes from the tappet chest cover), whereas the new one doesn't. I connected the breather hose that used to go to the carb to the fitting on the air filter instead, where the rocker cover vent (that doesn't exsist on my car) normally goes. Might this be the cause of the problem?

Indeed it is ! You need that rocker cover vent - and the carb with the side inlet is ideal - it saves the fumes washing over the air filter, and is much more efficient at venting the crankcase. The rocker vent goes to the carb! The tappet chest vent should just be open to atmosphere. But be sure to change that oil asap - the 20W50 stuff in ASDA at £2:75 is ideal for this - you can then afford to change it often. Your oil filter may also be water-logged - best chang it too.

Ah ok! Sadly the old carb was very worn and was causing the car to guzzle fuel - so putting that back on is a no-no.

My rocker cover doesn't have the outlet to connect the vent to the air filter - do I need to get a different one in this case?

Also surely if I get rid of the tube going to the tappet chest vent I should change the cover for a non-vented type or at least blank it off, as otherwise water and bits of muck could easily fall down it?

I'll change the oil and filter ASAP - i'll also drop the sump to make sure there isn't any sludge in there.

When you say using a bit of coolant , I hope your not expecting the level to stay at the top of the radiator inlet neck , as it heats up the water expands and blows out of the overflow and thel evel will always be about half inch below the rad neck, but it looks like all the car wants is an oil and filter change , cleaned out breathers and a good long run to get thoroughly hot.

As we all now know you have fitted the wrong carb to your Minor, you have
fitted an earlier type to a later model. If you are to retain the present carb
You need a rocker cover with the outlet pipe which connects to the air filter
and a tappet cover which has the swans neck breather pipe. If you go down
this route then note that you should fit an oil filler cap which is SOLID, there
should be no wire mesh filter in it.

Hmm I bought the carb new from Bull Motif Spares a few months ago and there was only one type available for 1098cc cars, but yes the new one is different to the old one.

Do you know where I can get a rocker cover and tappet chest cover of the correct type? - I've looked in various spares catalogues and I can't find any.

I'll put an ad in the 'wanted' section just in case.

If the old carb was worn in terms of drinking fuel, then have you considered just fitting a new needle and jet? Not really worth it if there's noticeable wear around the spindle holes in the body though (would need reaming out and bushing, which isn't cheap). Then you can have your original setup back

Without wanting to start the engine breathing arguments again, you'd be fine running the swan neck and rocker breather (when you get a breathing rocker box) to air - Just hang a bit of hose off the rocker breather and direct it towards the road or you'll get an oily fumy smell in the car.

If your head gasket has gone between an oil and water passage only you won't see water in the exhaust (other than the normal level from combustion) or other signs of combustion meeting water, because it won't be happening! Water in the oil and/ or oil in the water is what you'll get. A copper headgasket can be had for less than a fiver, and takes next to time time to fit - And you can give the head a good decoke while you're at it. So if sorting the breathing doesn't sort the sludge, it's not all bad

Early rocker covers are surely readily available - come on - someone near this lad must have one! And leave the tappet cover to breathe to atmosphere - but DO connect the rocker cover to the carb. BM have sold you a very old carb if it has no breather fitting on the side - just use the old carb. If it was using too much fuel it was probably the float valve leaking - just swop in the one from the 'new' carb. Your whole problem here is simple lack of engine ventilation - and it will destroy the engine having all that moisture circulating! You must get it breathing again.

OK i've disconnected the hose connecting the tappet chest breather to the air filter, and bought some engine flush to get rid of the goo.

Fortunately as it's Christmas at the moment I don't have to use the car much so hopefully I can get it sorted out with a new rocker cover soon. Shame that most of the alloy ones that are readily available don't seem to have a breather pipe on them.

As a tempoary meausre, I've let the tappet chest cover breathe to the atmosphere. Is it ok to leave it like this once I get the new rocker cover?

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Yes, it's fine. The earlier engines did exactly that.

See: http://potteries.mmoc.org.uk/Members_Ca ... 6B_026.JPG

That's exactly what I suggested ! But DO get hold of a breather type rocker cover - or just fit a breather to the one you have.

Yes,that's fine and,interestingly, if you retain your present rocker cover which
does not have a breather pipe in it then you will still be ok as long as you keep the oil filler cap which has a wire filter in it! This will let out any excess
pressure to atmosphere instead of into the air filter but at least it will be able
to breathe.

But the top of the engine will be all oily - and the fumes you can smell in the car are definitely not good for you!