Morris Minor Owners Club

Hiya everyone,

definitely one of those 1st time classic car owner questions where you have no idea if its normal or just how the cars are

Currently I am using my moggie as my commuter while I await repairs to motorbike which I usually commute on and the oil level is dropping rather quickly.
I am doing slightly under 200 miles per week with my commute being mostly above the 50 mph range - country road + motorway + dual carriageway with a chunk of slower traffic on both ends.
With this in mind, that seems to take me from being at the max line to the min line in around a week which to me feels excessive (I saw on another post this is roughly a pint worth).
I can't spot any leaks around the engine anywhere, nor anywhere further back such as to the gearbox where it could trickle from, no puddles forming under the car etc and doing the good ole go down a hill with engine braking then on the accelerator at the bottom and look for smoke trick to check for oil burning gives me nothing which suggests that oil isn't burning away.

So from drives at mostly higher speeds, I am losing give or take around 1 pint per 200 miles.

(1098 engine if relevant)

I do know that moggies are known for being, to quote Blind Man Morris "Enthusiastic Oil drinkers" so I am expecting more oil to go than modern vehicles but my gut feeling is telling me this is on the excessive side. Is my gut feeling right or is this actually rather normal and I'm overthinking it?

ta!

It’s an interesting question

We get similar consumption from the Midget 1275 on a run. I’m convinced the bores are worn but the compression test shows an even 165 across all cylinders. Occasionally a mile or so after setting off when we pull out at a junction we leave a cloud of blue white smoke and then it’s clear again. I suspect valve guide wear but I’m told many Midgets do this without any real reason.

The 1098 pickup engine uses very little oil. I’ve not added any in 2500 miles and it’s still at the maximum line. Of the two, this is the one I expect to leak as it’s always been run on Duckhams 10W40 oil. I don’t know why but that’s what the previous owner was advised to use after a rebuild ten years ago.

You'll get a lot of different answers I suspect. Before my 1098cc engine was rebuilt it was rather clapped out and had not had any major work in over 100,000 miles. The compressions were good and even across all cylinders but it used a lot of oil and the oil consumption was dramatically increased by long runs on dual-carriageways at 50 mph +. At worst on such runs it was using a pint of oil per 100 miles which was terrible! It never made blue smoke but the spark plugs were always oily. Since the engine has been rebuilt the oil consumption is absolutely minimal. Looking back, with the worn out engine it always did have an exhaust smell of burning oil but it never burnt so much that it could be seen as smoke.

Stephen

Try running at midway between full and low on the dipstick. When I first got mine, I ran it at full and it needed regular top up.
Since running at the midpoint it uses less. Not sure if it less leakage or burning but either way the difference is notable.
Also worth checking, whichever type of crankcase breather your model runs is working correctly.

Your gut feeling correct - 200 miles to the pint is excessive.!!
I suspect the valve guide seals and possibly worn valve guides.
I suggest that you remove the head and replace all the guides and inlet guide seals. Replace the inlet valve seals with the top hat seals. The guides should be the ones with the groove for locating and securing the top hat seals. You only need to fit top hat seals to the inlet valves as that is where the oil gets sucked into the engine and consumed. The exhaust valve guides do not need seals as they need all the oil they can get as unleaded fuel has no lubricating qualities unlike the leaded fuel as originally used. All the parts you require are available from ESM.

I agree with PTH re the likely head overhaul. However, the grade and quality of the oil in use has not been stated.

As an example, I had a 480 volvo which used as little as half, while using a semi-synthetic over the usual paraffinic oil at the time. A more expensive lubricant but better/cheaper overall.

Have you checked the plugs for deposits? They may provide a clue if one cylinder is worse than the others.

philthehill wrote: ↑Wed Jun 03, 2026 7:01 pm Your gut feeling correct - 200 miles to the pint is excessive.!!
I suspect the valve guide seals and possibly worn valve guides.
I suggest that you remove the head and replace all the guides and inlet guide seals. Replace the inlet valve seals with the top hat seals. The guides should be the ones with the groove for locating and securing the top hat seals. You only need to fit top hat seals to the inlet valves as that is where the oil gets sucked into the engine and consumed. The exhaust valve guides do not need seals as they need all the oil they can get as unleaded fuel has no lubricating qualities unlike the leaded fuel as originally used. All the parts you require are available from ESM.

Thanks for the replies!

Looking on ESM, by top hat seals do you mean the spring types rather than the O-ring types (10M186A)?
Not done work on an engine head before so it'll be a fun weekend experience for me with the workshop manual and some youtube

For Oliver's questions too:
Been using classic 20w50 oil. Typically use the castrol stuff from esm but recently been topping up with the stuff from halfords since was easier to head through to grab some on short notice.
Last checked the plugs just under 1k miles ago and there was no sign of any deposits but I'll be giving them a check over again when I have a look at the head. Be doing a full visual once over of everything before doing any dissessmbly bits anyways lol

The top hat seals are ESM Pt No: 10M186A.
The valve guide with groove for the top hat seals are ESM Pt No: 10M170GJ.
The fitment of the valve guides and top hat seals is a easy job. To get the valve guide at the right height do one at a time and put a rule across the tops of the valve guides to get them all the same height.
The dimensions of the drift required to drive them out and then drive the new ones in is given in the BMC wksp manual.
Below is the tool I made from the given dimensions.