Oil leak

[53lake]

Restoring my 1968 Traveller in Central Texas, and got the engine back from the body shop who subbed the engine out to a local machine shop to do a "complete" overhaul. Actually I'm not sure exactly what was done to the engine as I have no itemized bill, and didn't deal directly with the machine shop. I did provide them with a lot of engine parts I got from ESM, among them a crank rear oil seal conversion kit, 10M800.

I fitted a new clutch, attached the gearbox, and put the engine back in the car to try it out. It ran fine, but immediately started leaking oil, badly, from the drain hole at the bottom of the bellhousing. I probably saw a couple teaspoons in the pan within an hour of running the engine for the first time. I know it isn't coming from the gearbox, because I drained that completely, renewed seals at both ends, and I haven't refilled it because I haven't attached the propshaft yet, so just left in it neutral while checking the engine ran OK.

So the leak must be coming from the rear of the engine??? I'm not sufficiently familiar with the potential sources of a leak, but with a sinking feeling realize I have to take the engine out again.

So I can discuss this intelligently with the shop that did the work, can someone advise me what the likely cause is? I do see postings saying the crank rear seal conversion kit may not be effective without cleaning up the shaft surface, but I find it hard to believe the amount of oil I saw coming out could be a result of that.

Left the engine alone for a couple of days, leak has definitely abated while cold, but just ran it again for 10 mins and another teaspoon or so lost in 20 minutes after shutting off.

Grateful for any advice - thanks!

[don58van]

I regret to say that if you do search on here for engine rear oil seals that you will find many findings that it is a failure. It is just about impossible to make it work correctly. It is almost certainly the source of your problem.

Don

[pgp001]

Has your engine got good crankcase breathing ?
If not that will make the problem a lot worse.

Phil

[simmitc]

As above, whilst I have not used the kit from ESM, I have tried similar items and they were a complete waste of time and money. The Minor crankshaft is not designed or machined to accept a lip seal of any sort. A reconditioned engine with good breathing is the best cure. What you have to hope is that the machine shop kept any parts that they had to remove to fit the kit, and that you can get everything restored to standard.

[philthehill]

Unfortunately unless you know exactly what has been done, seen what has been done and understand what has been done I hold out little hope that you or the machine shop will be able to do anything about improving the rear seal conversion situation.
Unless you or the machine shop have retained the top half of the oil thrower housing you will not be able to discard the seal kit and go back to the ex factory type of oil control at the rear main bearing.
Having had negative experience of the rear lip seal conversion and the positive building of many BMC 'A' series engines I personally would not fit a lip seal conversion kit to the Minor engine. The engine was not designed for its installation and the lip of the seal is totally dependent upon the finish of the rim of the crankshaft flywheel mounting flange. The rim of the flange should be ground mirror finish for the seal to work successfully. If the rim of the flange is not absolutely smooth the lip of the seal can tear and make the seal useless. The depth of the flange is also critical. Some kits have a thin spacer to fit between flywheel and crankshaft to increase the available width of the flange.

I would advise against running the gearbox without oil even to test the engine as the bearings can pick up and get damaged.

Below is the part you must retrieve or have in order to go back to the ex factory means of controlling oil seepage at the rear main bearing.
This part is removed when fitting the oil seal conversion kit.

rear cover 1.jpg (508.34 KiB) Viewed 1854 times

Rear cover 2.jpg (532.94 KiB) Viewed 1854 times

[ampwhu]

This is why I left this piece exactly where it is on the block when I left it at the machine shop. I gave strict instructions to leave it there in its place.

[philthehill]

There is no black art in setting the upper part of the oil thrower housing.
Well described in the Marina workshop manual which is well worth the purchase as it has all sorts of information relative to the 1098cc and 1275cc power units which is not included in the Minor workshop manual.

[ampwhu]

I've just purchased one for £5 delivered.

[53lake]

Thank you all for the constructive replies. Having re-read the instructions that came with the conversion seal kit, I can see how important the condition of the running surface is.
Interestingly, having run the engine for another 5-10 minutes, the leak has lessened. After cooling down overnight, there's no more than one drip in the pan. Still, I'll take the engine out again, dismantle the assembly, and see if the surface condition needs work before re-installing with a new lip seal.
New rings and bearings were installed, so I hope there isn't excessive crankcase pressure or lateral play in the shaft.
I've contacted the workshop, and they will have a look to try and locate the original part, but I doubt I'll be lucky - I've waited 10 months since getting the engine back to get it into the car My bad.
If I have to go back to the standard fitting, where could I source that part? It looks scarce as hen's teeth. ESM, Charles Ware and Moss are the main go-to sources I know of. There's a Morris Minor specialist in Oregon I will try in the meantime.

[philthehill]

If you cannot find the original part your next option is to find one off a scrap engine.

[53lake]

The shop found the part! Hallelujah!

[philthehill]

Well done.

Now get them to throw away that seal kit and go back to standard as regards the rear main bearing oil control.

Phil

[Declan_Burns]

Phil is of course correct but there is a possibility that an SKF Speedi sleeve can be fitted to the flange. There are some kits available (for MG's) that include such a sleeve. I have not tried it. It is also important that the lip seal is designed for the correct angular velocity of the crankshaft. I would use a Viton seal.
Regards
Declan

[Murrayminor]

Well done.

Now get them to throw away that seal kit and go back to standard as regards the rear main bearing oil control.

Phil

https://www.med-engineering.co.uk/med-i ... n-seal-kit

Is this a similar kit?
I take it you suggest running the standard scroll seal rather than these?

[philthehill]

The MED seal kit is a completely different kettle of fish which is reflected in the purchase price.. It is a kit I would use if needed but I have never had problem of oil leaking from the rear main. The main difference is that the seal does not run on the rim of the flywheel mounting flange.
See the MRD video about the differences between the transverse and in-line 'A' Series engines and the seal kit is shown and explained towards the end.
Phil

[Murrayminor]

The MED seal kit is a completely different kettle of fish which is reflected in the purchase price.. It is a kit I would use if needed but I have never had problem of oil leaking from the rear main. The main difference is that the seal does not run on the rim of the flywheel mounting flange.
See the MRD video about the differences between the transverse and in-line 'A' Series engines and the seal kit is shown and explained towards the end.
Phil

It does seem to be an issue that some engines seem to suffer from rear main seal leak whereas others don't , would that be down to maintenance or just plain wear and tear I wonder.

[philthehill]

https://www.youtube.com/watch?v=9sxy1pU ... ex=61&t=0s

From 4 minutes 19 secs onwards the seal kit is described.

I put it down to maintenance - whether that be worn piston rings, worn bearings, general wear and tear.

The bearings in my engine were changed every engine rebuild which was at least once if not twice a year. The piston/rings were always checked at the same time.

[Murrayminor]

The MED item certainly looks the part, and the fact it doesn't come with a tube of Holymar speaks volumes.

[Matt]

I haven't watched the video (not appropriate at the moment...) but it seems as though the MED kit doesn't need a smooth surface to seal against? That seems somewhat counter intuitive to me and im not sure how they achieve oil-tightness.

I have a 1275 spridget engine to rebuild (as soon as I have the finances) and was wondering how I would deal with the scroll seal. If this kit actually works I would spend the money...

[Murrayminor]

The short clip in the above video shows where the seal sits on the crank, it does appear to sit behind the scroll seal on a machined surface of the crank.

It appears to seal against the crank and also into a recess on the actual u shaped clamps (for want of a better word) which then bolt to the block.

The video tells the story much better than I can describe.