Morris Minor Owners Club

I'm hoping someone might have come across the same problem as I have. The 1098 engine in the car when I bought it was dropping significant amounts of oil from the drip hole in the gearbox bellhousing so I decided to rebuild my standby engine (also a 1098). All has gone reasonably smoothly except having fitted it into the car, there is a major leaking of nice clear oil on to the garage floor!

Both engines are fitted with the after-market crankshaft oil seal conversion kit which replaces the half-moon seal that goes on to the block with a circular seal with a sprung oil seal which rubs on the crankshaft's flywheel mounting flange. The idea is apparently that a seal round the whole of a flange is better than the semi-circular seal which relies on mating with the crankshaft inside of the flange.

I have had experience of these after market seals before and they have always leaked badly. I seem to recollect from reading Vizard's book that they rely on a perfectly machined surface to the flange rim for a perfect seal to be made and of course little of the A series engine is perfectly machined except where absolutely necessary!

Has anyone else had problems with these after market seals and if so were they able to fix them? I would prefer to go back to the original half moon seal so has anyone got one spare sitting in their box of bits?

Thanks in anticipation!

Chris

I've never bothered with these seals - now you know why...... The reasons for crank tail leakage are - worn main bearing allowing the area to be flooded with oil and/or crankcase pressure which blows the oil out past the standard labyrinth seal. And of course if the labyrinth on the crank tail has been damaged in the past - there is no hope anyway. Perhaps you can smooth out the crank flange with fine emery - and fit a new seal to the housing? But I imagine that seal must run constantly flooded with oil - so it's got quite a job to do.

In my experience the aftermarket seals are a complete waste of time and money. You have already identified their failings, and you realised that they are doomed to fail. As Roy says, the reasons for the leak without the seal are well known; and a good reconditioned engine will not leak for many thousands of miles. Take the silly aftermarket thing off!

I have it on mine and have had no leaks since-the problem is the machined surface-read this:
http://www.mmoc.org.uk/viewtopic.php?f= ... ft#p362735
Regards
Declan

Chris,

What crankcase ventilation system does your engine have? To avoid sump/crankshaft related leaks the whole crankcase must have a slight vacuum in it to prevent oil leak problems.

Thanks for your comments everyone. I have had this problem before where the aftermarket seal was fitted to the engine of the Traveller I had when I bought it and in the end had to use the standard part off my spare engine to stop an appalling leak (a pint in 10 miles!!)

I now have the same problem with this new vehicle. I came to sort out what I assumed to be a leaking oil pump cover only to find another of these blasted after market jobbies and this time no spare standard part to swap it with. I take your point Declan and if I had the patience I might consider having a go at cleaning up the end of the crankshaft but I have lost all faith in these gizmos. I know from reading Vizard that the engine must be well vented and I have the standard pipe fitting to the front side tappet cover. Before I took the engine out, I tried running a pipe from that into a plastic jar to act as an oil catcher and then to the vacuum input to the 1.5inch carb that I have fitted. It looked the part but wasn't man enough to keep the oil in the engine! Also I wasn't too happy that I might not get a blow back into the sump and that all that dirty air from the engine was going directly into the cylinders.

I have now put a "Wanted" ad in the parts section of the forum and hopefully someone will come up with a standard part on the back of an old block.

Thanks again for all your thoughts.

Chris

You need a tappet cover with a breather pipe that goes into the carb.

That's what Chris describes above...... Your only hope for that part is a wrecked block somewhere....... the oil pump never leaks - how could it??? If the engine is out anyway - I would inspect the main bearings - and the rings/bores. This problem comes directly from crankcase pressure - which is not present in an unworn engine......

If you have a crankcase ventilation intake on the carburettor (HIF4?), then run the tube directly from the tappet cover, or seal up the tappet cover and take it from the timing cover or rocker cover and fit a vented oil filler cap. That way you will get a controlled partial vacuum, which, apart from a really worn out engine, should control the leakage from the scroll.

Whatever you do do not seal up the crankcase and still use a non-vented cap - you will suck more than fumes into the carburettor!

I'm not a fan of the strange vented cap - leads to mess on the rocker cover and nasty smells in the car. What has always worked for me, on all my various engine (Minor and Mini) is a tube from rocker cover to carb, and the cam follower cover breather left open and extended down so it hangs in the slipstream just below the engine bay. If no cam follower cover - then the timing cover breather can be used instead. But for me - it's important to pull some fresh air through the block to remove moisture, and when the engine is working hard it allows any excess fume to escape without making a mess or causing nasty carcinogenic smells.

I'm not a fan of the strange vented cap

I've used one for the last 14 years on our 1380 engine, and have never had a hint of oil from the cap or any fumes. It is designed to work with a positive extraction system, such as the port on the HIF series carburettors, and creates the controlled partial vacuum that helps to keep the oil inside the engine. Interestingly I fitted a timing belt conversion for a couple years, and it only had a small hole to vent from the timing cover - the oil consumption leaped from 1,000 miles per litre up to at best 200, complete with significant drips from the rear of the engine!!

Restoring the timing chain with its original timing cover breather immediately restored the oil consumption back to the previous level, and all but stopped the rear drips. Nothing else was changed, so that convinced me even more that a proper positive crankcase ventilation system is essential to in-line A-Series engines. Transverse Mini's are different, as they have a 'proper' rear crankshaft oil seal!

With any open pipe or vent (rocker cover etc.) there can be no vacuum, as there is no restriction to the air flow being created by the carburettor or inlet manifold, so nothing to help the rear scroll retain the oil and little to stop oily fumes escaping from a vented oil filler cap. There will be a general pull through of fumes, but that is all. An 'open' system should have a non-vented cap and closed-circuit should have vented!

Each to their own - I simply list what works for me. My engine is oil tight and fume tight. The Mini has NO rear crank seal - the oil just spills down into the gearbox and/or transfer case.......

No rear oil seal? What stops the engine/gearbox oil from reaching the clutch?

The transfer case has a seal into the flywheel section. It also leaks like mad if there is pressure in the crankcase.......

And the seal runs on the crankshaft, just behind the flywheel?

Yes - but it's not a 'crankcase' seal in the same way as the Minor seal....... It's a transfer case seal!

Roy, the point I am making is that the rear seal on the crankshaft on a Mini is a conventional lip seal, in comparison to the scroll on the in-line engine. Whether the crankshaft seal is fitted at the end of the block or a bit further back in the transfer case does not matter, it the last thing the engine oil sees before the outside world! And in the case of the Mini, the gearbox and final drive oil as well.

The Minor in-line engine scroll needs some help from a partial vacuum to retain the oil inside the engine reliably, whereas a lip seal just does not want any real positive pressure behind it, so an open vent on a Mini may well work quite satisfactorily.

Yes -I see full well, but believe me - the Mini engine needs vacuum too or that seal leaks very badly and/or oil is forced past between the primary gear and the crank tail. The vacuum system is every bit as important as on an inline engine. It also saves oil being pushed up past the rings......

Totally agree, I do not advocate an open system on any A-Series engine.