Morris Minor Forum

Oil leaks that appear and get worse over time in an engine that has not been messed with are most commonly related to engine wear.. the rear main leaks when the bearings clearances increase over time.. you can spend a lot of time replacing various gaskets and arseing around with the oil pump.. next time you get inside there pull the centre main bearing cap and examine the condition of the lower bearing shell.. if any wear is obvious.. you have probably found the root cause of your oil leaks and the main bearing wear should be considered the messenger.. meaning..rest of engine is similarly comprimised... a proper rebuild will resolve the issue decisively.. you could of course have poorly fitting gaskets etc.. that is common when they are pulled apart and not assembled with sufficient attention to detail ..

How many nails did you come across
whose engines leaked simply because the
sump bolts had come loose please Timothy?

frankly its rare to find loose sump bolts in an engine that is 'original'.. having stated that, its also true that there can be huge variations in initial quality..there were no CNC machines and strikes by disgruntled workers were common 'back in the day'.. Oil leaks due to age and use are very common.. and even more common when someone has taken off the sump to investigate issues related to oil leaks and re-assembled it carelessly.. BMC A series engines leak oil..the quality of them varies considerably.. it was not unusual to find growly main bearings in the 1098cc engines before they had covered 30,000 miles.. others might run 80,000 before same issue reveals itself..(a common fix to resolve the issue fora few years was to drouth sump and replace just the centre main bearings shells in situ..and then retard the timing back few degrees to keep not quieter. Proper careful assembly with close attention to detail can improve matters.. balancing the internal components can yield good improvements over smoothness and longevity.. its not unusual to have connecting rod weights vary by 30 grams or more in a set.. vibration tends to help unsettle things and make oil leaks worse..The engine in my current '67 vibrates so badly it rattles the cars windows .. its never been opened up as far as I can tell and was likely a poor example from the get go.. given the abundance of 1275 engines ( and plenty of the 2" main bearing '10CC' version..unique to sprite midget) available for little outlay.. I rarely bother to rebuild a std 1098cc engine today.. they are more practical routes to gaining a good engine..

Your post brought back happy memories Timothy
The machine shop I used routinely bored
mains on blocks, and big ends on rods
because garage frequently ran bearing caps
across a surface grinder, and then shimmed
to get about the right clearance.

No pratting about with poncey "Plastigauge" in they days,
proper mechanics shimmed until the bearing was a bit tight
and then added another shim

I thought self loosening sump bolts were a design feature .
Why else didn't they have any form of locking?

Carefree days

Mike D :- indeed..these sort of 'fixes' can still be done on a simple car such as the minor for those on a tight budget.. but for moderns the standards are very different.. the the minor was in production an 'average' mileage was 12,000 miles per annum.. and often considerably less... most cars today rust away before the engine gets tired.. and its unusual for a modern car to have engine issues before 150,000 miles .. it was possible to get another few years out of minor with repairs of the type you suggest... some garages re-bored the cylinders with engine in situ ( part of the reason why Hepolite came up with those awful 5 ring pistons.. most Uk machine shops did not finish hone cylinders after re-boring.) here in the USA the 1275cc engine is far more common than any other A series...so it makes no sense to re-build either a 948 or 1098.. the unique to '67 model year sprite/midgets have quality engines.. they came with both an EN 40 steel crank and hard cylinder liners from the get go .. '68 on has a reduced cost version.. the 1st year 1275 engine is a cracker..

Got it resolved. It was crank case pressure. I added one of these breather kits and i had 3 small drips after shutting off.

Really glad you you got the issue solved. How about a few photos of what the kit you bought looks like installed.

John F. Quilter
Eugene, Oregon USA

No problem John. I was doing a test with some clear hoses to see if any oil would enter into the hoses, but after a 20 minute drive, there was absolutely no oil whatsoever. Also the vent tube, I added an oil catch to see how much oil would drop out and it was dry! I was dumbfounded! We also added another drain tube on the rear tappet cover, but not sure if that one is necessary. I'll post some pictures tomorrow. Here is my oil catch system; a BMC original design...Lol

Greg, I did that same catch can test on my convertible maybe 30 years ago but finally settled on a retrofitted 1967 style factory PVC system. Keep in mind that the catch can idea does defeat the purpose of the "draft" tube which is supposed to have air blowing by its angled cut off in theory creating some minimal draw on the crankcase. The Morris brain trust will argue/discuss for days whether that really works. And just for the record, my 948cc Minor convertible has a PCV system, the 948cc sedan does not.

John F. Quilter
Eugene, Oregon USA

Is "Brain trust" a put-down in the States as well please John



Edited 1 time(s). Last edit at 2017-03-13 04:45 AM by 0123.

Does your kit do any more than make
another hole in the crankcase please Greg?

Mini Mania Crankcase Ventilation Kit, C-2A265

Read all instructions thoroughly and check parts list before starting
installation.

General
This kit provides an internally baffled housing which enables the fuel pump port on the engine block to be used to vent the crankcase. The kit also includes fasteners and gaskets to mount the fitting but does not include a hose fitting and hose.

The fitting is tapped to accept a 3/8-18 NPT fitting. Fuel/emission hose of 5/8" ID is recommended and clear plastic tubing is readily available, but an equivalent size AN line can, of course be used. Whichever type of line is used, it is important that the line running between the fitting and its destination (air cleaner, catch tank, etc.) not form a loop or "sump" below the level of the fitting you've installed. If this happens, oil can accumulate in that loop and be blown out as liquid by crankcase pressure. As you might imagine, this could make a mess of things under the hood.

This kit may be used with any "A" series engine having an engine block with provision for a mechanical fuel pump.

We further recommend that some sort of "catch tank" be installed for the hose to drain to. This tank is need not be anything special, an old radiator overflow bottle or a second window washer bottle would be ideal. They are generally mounted on the firewall or some other appropriate location which allows it to be easily emptied. The tank should be vented so that no pressure buildup is possible.

Installation

Afix a 2A113 gasket to each face of the 3A0012 Vent Housing. The use of a contact-type sealer such as "Gaskecinch" (available through Mini Mania) is recommended.

Remove the fuel pump blanking plate and retain. Remove the two attaching studs from the block and remove old gasket and residue from both the blockand plate.

Position the plate over the face of the housing having a rectangular cutout and attach this combination to the block with the fasteners provided. Refer to the illustration.

Install your choice of hose fitting in the housing using (preferably) Teflon thread sealer, attach the hose and complete the plumbing.



Parts List for Breather Kit (C-2A265)

Item Part No. Description Qty/kit


1. 3A0012 - Vent Housing 1
2. 12G3494 - Gasket, fuel pump 2
3. HC0518 - Bolt, 5/16-18 x 2.25" gr5 2

https://www.minimania.com/Mini_Mania_Crankcase_Ventilation_Kit__C_2A265

Grinding bearing caps on a motor with thinwall bearings
was nothing more than a bodge to scam a mug into shelling out
his hard earned in order to shift a knacker off the forecourt.

Some prewar motors came with shims and thickwall bearings.
Removing shims in such motors was normal.

Over here, motors go down because the electronics go crazy

'bodges' were common back in the 60's and 70s to get cars back on the road..(and are still done today by people who dont know any better) it takes under an hour to replace a loose centre main bearing on a growly 1098cc minor 'in situ'.. and yes.. many impecunious outfits would file or grind bearing caps to 'get er back on the road'.(most people rarely commuted more than 5 miles from home to train station or workplace and back when these cars were current and life was simpler)
Amused about all the fuss of adding extra vents for the crankcase.. personally i never bother to add a pcv valve.. but make sure I have the early (or home market spec) top vented valve cover .. with tappet cover vent and valve cover vent there is sufficient ventilation even for a tired old engine with serious blow by .. a 'hockey stick' style tappet case vent rarely gets enough oil build up inside it to drip unless the engine is knackered or close to it.....each to their own I suppose..'keep it simple' has always been my approach.. they aint making any more time..

Ah, the 60s were carefree