Morris Minor Owners Club

My 1971 traveller uses about a pint of oil on a 300 mile run at about 65 maximum. I am considering a rebore and unleaded head rebuild over the winter.
I'm not worried about leaded fuel as my local sells real leaded 4 star.
Ok here are the figures

1098 high compression 68k on the clock - no history I do about 5000 a year

Oil Pressure cold 45psi at tickover 75psi at 50 mph

when warmed up ( 20 miles) t/o 40 psi and 70psi at 50 mph

compression test

Dry 1) 140psi 2) 140 3) 145 4) 135
wet 1) 175psi 2) 165 3) 170 4) 165

No oil on the spark plugs and no smoke from the exhust.

Do I need to do any thing? Is it worth the trouble of reboring?
If I do take the engine out would I be well advised to replace all the shells and the Oil pump? Any suggestions for where to get the rebore done around Bedford?
How many miles per pint of oil is reasonable for a morris?

I'd be quite happy with these figures,maybe check for oil leaks,my 1969 2 door returns similar ones at 99K but I do have a couple of leaks which I havent got round to fixing yet.As to unleaded head its a question of do you want to spend the money,in the long term youll save on cost per litre.I fitted an unleaded head,but part of that was due to a faulty old one.It came complete with valves and springs for about 150 exhange from Mr.Grumpy in 1998 and its been fine.Did improve the compression psi as i had a leak between 2& 3 due to the head.Hope this is of some use to you.

I would query you oil pressures as the max for the 1098 as
designed is 60 psi !! are you losing a lot through the drain hole
in the clutch housing?? I too would think that there is a lot of life
left in your engine and yes, it is always sensible to renew the shells
and oil pump if the engine is out though,with those pressures you
certainly do not seem to have a 'pressure loss' problem! In the
days when the Minors were new the factory always said that
"500 miles to the pint is within specification"!!

I think the gauge probably reads high. The important thing is that the pressure do not drop off when it warms up , not the actual readings
obviously it isn't a calibrated gauge.

Does any one have suggested figures for compression?

There is only the ocassional drop of oil from the clutch housing.
500 miles to the pint sounds good - perhaps 300 to the pint isn't too bad.

Figures for compression.
On my (I think) 1965 Gold Seal 1098 engine, which has done about 80/90k? miles and never had the head off, I get
cold hot
160,160,149,150psi 145,150,140,140psi

The last 42k miles have been lead free without additive.
Regards, MikeN.

Sorryabout the spacing of the cold and hot words above. Cam's put me right elsewhere about how get gaps.
Cold test I get 160,160,149,150psi.
Hot test 145,150,140,140psi.
Tese were done with the throttle closed. I know Bmcecosse always says do it full throttle which sounds sensible.
MikeN.

YES, a compression test should be done with all 4 plugs removed
and the throttle open. I must admit I don't see the point of a gauge
which is not reasonably accurate.

I would consider fitting new piston rings rather than a complete rebore.

It is much cheaper and there is a limit to the number of times that an engine can be rebored before it needs to be relined.

160,160,149,150psi 145,150,140,140psi

The last 42k miles have been lead free without additive.
Regards, MikeN.

My traveller is currently 100, 110, 100, 0

Previous owner wasn't using an additive and had to replace a valve, however by the amount of oil that is now being burnt, it really wasn't worth the effort of replacing the valve!

I think your figures speak volumes re using unleaded with no
additives in an unmodified head Ray. There will always be some
who seem to get away with it but if you indulge in high speeds it
seems that the heads are in grave danger!!

What do you think of the idea of only replacing the rings ? This sounds attractive since I could do it with the engne in place. I have a ring compresssor thing for getting the pistons back in. Some where in the deep recesses of my memory I seem to remember its not easy to get the new rings on.
While I have the head off is it cheaper just to get the valve seats replaced and perhaps new valves rather than going for a replacement leadfree exchange head. any ideas on costs?

Well, if you are replacing the rings, I would hone the bores first so that they 'bed' in properly. This is assuming of course that the bores & pistons are in good condition and within tolerance. You can buy drill attachment bore honers from Frost or Machine Mart I think.