Morris Minor Owners Club

Took my ’59 948cc tourer out this morning for its first run after new valves, exhaust, clutch, radiator, water pump, alternator etc and new interior. Pulled nicely, no strange noises, no overheating. Only went about 8 miles. Back home noticed a small oil leak from the timing chain cover so nipped up the setscrews at the bottom which were a bit loose. All in all though quite pleased as I’m no expert when it comes to cars.

Then it happened. Started up to check the leak was fixed and a great jet of very black oily, watery looking stuff spat out of the (new) exhaust. The oil light, which was fine when I'd run the engine before now won’t go out. The oil in the sump is new and clear and the sump is full, very different from what shot across the floor and up the wall of my garage. However the engine sounds ok and after the initial blast the exhaust gas looks pale white like it is running on a bit of choke. Haven’t run it for long though due to no oil pressure.

The plugs (all brand new) from 1&2 cylinders are very oily, from 3&4 not so black but still not clean. There seemed to be a small amount of water bubbling from the side of the plug in No. 2 cylinder although the plug was tight.

Did a couple of compression tests on each cylinder, first without oil. All psi. Engine warm.

1 – 143 – 147
2 – 140 – 142
3 – 142 – 135
4 – 130 – 138

Then with a drop of oil in each bore.

1 – 155 – 152
2 – 180 – 185 (Bit too much oil !!)
3 – 160 – 155
4 – 150 – 150

Thinking back, when I took the head off to decoke and fit valves, the waterways in the block were very silted up. No water came out of the tap on the block when I firs opening it and I spent a lot of time when the engine was out unblocking the waterways, mainly poking with a coathanger wire, nothing corrosive, and then flushing and reverse flushing using clean water from a pressure washer when the head was back on. Compression before fitting the new valves was also way down, in the 110-120 range.

Could it be that the higher compression and unblocking the waterways has uncovered a weakness that wasn’t evident before. Or is it something worse? Where do I look next please?

First priority is the oil pressure worry. Is there REALLY no oil pressure, or is the switch faulty. You NEED an oil pressure gauge - although if you have another switch to try - do it. You could have a look at the relief valve to check it's not jammed open - only takes a few minutes. The comp readings are 'ok' for a 948 - but did you retighten the head nuts (44 ft lbf) after the first heat cycle? And then reset the valve gaps...... 12 thou inlets and 15 thou exhausts.....

Thanks.

Checked the connections to the OP switch but not the switch itself. Don't have another but will check at least if the current one is short circuit and will obtain a pressure gauge.

The words 'relief valve' had me diving for the big blue book. As I said, no expert. Hadn't noticed there was one Found it now - in the book - will check it tomorrow.

Haven't redone the head nuts before as tbh haven't had it running long enough before to think it was a 'heat cycle' i.e. I don't think the 'stat had opened. Was going to do it after the run today, but guessing on reflection should have done before.

Set the valves to 12/15 thou when the head was refitted but will reset tomorrow.

Thanks again.

I wouldn't run it again until you KNOW there is oil pressure. Take the plugs out and crank it on the starter to get oil pressure up for tests.

Yes. thanks, wasn't intenting to run engine until finding out what is going on. Question: plugs out when doing OP test? Should piston rings give adequate seal for the test? I did notice that when doing comp test with oil that the pressure declined rapidly to around 120 psi on cyls 3&4 accompanied by an audible hissing. Didn't hapen without oil.

Oil pressure is nothing to do with compression test. Oil pressure is only at the various bearings......let's sort that out first!

Thanks. Will do tests & advise.

Took the relief valve out. All looked ok. The silver bullet shaped thing was clean and ran free in the bore. The spring was 74 mm long, manual say 73mm so I guess that is ok. Retorqued the head nuts to 44 ftlbs although I didn’t feel any of them actually move. Checked the clearances at 12 & 15 thou, all were fine and didn’t seem to have moved from where I had set them before.

Bought me an oil pressure test kit. Attached where I’d removed the OP switch. Cranking without the plugs as suggested gave an initial 60 psi dropping back quickly to around 52 psi. Guess the switch is dead then although I don’t have any way of testing it. Anyway, thanks for that tip, will order a new switch.

As there was oil pressure, put the plugs back in and started the engine. Oil pressure when running is 45-50 psi at idle rising to 60-65 psi at increased revs.

Another great pool of nasty black water came out of the exhaust the first time the engine started, but not the second although there is still a little oily water dripping from the exhaust on tickover. Also the plugs, which I’d cleaned are again covered in very black oil although the oil on the dipstick is clean & clear. I’m still concerned that there is water and oil mixing in the engine.

Well done - I think it is just crap lying in the exhaust - you'll be fine ! Is the oil pressure gauge not going to become a permanent feature inside the car??

Was thinking the very same about the gauge myself. Thanks for all your help.

i would not worry they all create some h20 when they start up oil pressure sounds fine as long as you dont have blue smoke comming out of the exhaust and its not loosing loads of oil just use and enjoy the car

Thanks also. No, exhaust smoke is a good pale colour. Will keep an eye on the oil consumption as I start using. Provided of course it doesn't all disappear out through the (new) felt seal on the timing chain cover first.

I take it that you have had the timing cover off to do the seal,you do know to fit the pully to centralize the cover before tightening up the bolts.If not then it will leak from the seal.If you didn't ,then simply slacken off All the bolts with the pully in place and re tighten.

Yes, that’s right, took the cover off to change the seal. I didn’t realise that something seemingly as simple as removing a bit of tin, renewing the seal and replacing could have possibly needed a 2 stage tightening operation. That is until the seal started throwing oil all over the (recently painted) engine, the underside of the (cleaned) bonnet, my drive etc. I'm not bothered about the drive but I worked hard on the engine bay.

Only then did I do a search for ‘felt seal’ on here, where multiple times this has been mentioned. I must take this as a valuable lesson. Even the most innocuous operations on this vehicle can lead to locked doors and the secret keys for these doors can only be found on here.

Thanks for the note about part undoing the bolts and realigning. I did try slackening them off a bit but gave it up as I couldn’t see how it might help. I had visions of taking the radiator out and undoing the starter dog nut to fit a new seal. Presumably I need to loosen the bolts then completely break the timing chain cover seal and wiggle the cover about / turn the engine a few times with the handle to line things up properly?

sooty plugs are from the oil in the cylinders during the compression test. that will burn off with a little driving.

You will do far better to get a later timing cover with the rubber lip seal - it actually seals the oil in.......

Thanks David W, that's good news. Plugs are quite oily not sooty but will see what happens on a a few runs.

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If the wigglin' an' a jigglin' with the timing cover & felt seal doesn't work, happy to change to later type but can't find from web suppliers. Will keep a lookout in the 'For Sale' on here I guess.