Engine Oil Leak

[jaguar68]

Hi Chaps,

I know someone will be along soon to tell me to search, but there are about 4000 returns for leaks (oil or otherwise).

The question is this. My 1275cc Ital A+ engine leaks from the rear. From what I can make out this is possibly due to oil being forced out of the rear scroll seal. The received wisdom for this is due to excess crankcase pressure.

The engine is set up with a HIF44 carb on an alloy waterheated manifold, breathing through a K&N air filter on a LCB exhaust. As far as I'm aware, the engine breathers are connected correctly, with the breathers connected to both the carb and the main can type breather on the front of the engine. There is no breather on the rocker cover, by the way.

Is there any way to clean the breathers, including thecan type breather, other than cutting it open?

There is evidence of a "weep" from the sump nut, but I'm not sure if this is from the plug washer or referred from the leaking from the rear plate.

Any suggestions?

John

[JOWETTJAVELIN]

The 1275 is perhaps the most durable of all the A Series engines.

I have no experience with one being fitted to a Minor, but you could check the sump nuts for tightness. (By which I mean the nuts holding the sump in place - not the drain plug).

How much does it leak? A little drop you can live with but it is more serious if the car leaves quite a mess.

[jaguar68]

The leak isn't too bad I guess, but enough to need a biscuit tin filled with cat litter to take up the drips. Over time it all adds up and leaves an oily patch to contaminate the tyres

[mike.perry]

You should see my front drive!

[jaguar68]

If I were closer to Reading Mike I would take you up on the offer!! trouble is, Gladys lives on the road, and the slick is getting a little embarrassing

[bmcecosse]

The timing case can can be cleaned with solvents - or by setting it on fire...... Obviously it needs to be removed from the engine first.... I encourage use of a rocker cover WITH breather pipe.

[jaguar68]

Hi Roy,

With the rocker cover with breather, where does the breather go? Something, not sure what at the moment is already breathing into the carb/air filter.

Regards

John

[bmcecosse]

You can join them with a T - and lead it to the carb - NOT the air filter. If the engine is breathing heavily - you can connect them to the inlet manifold directly - through a 1/8" dia restrictor. I had to do this with a Mini engine and it worked well!

[IslipMinor]

with the breathers connected to both the carb and the main can type breather

John,

Not sure what you mean? Do you have a picture? Do you have separate breathers on the timing cover and carburettor? There should be a hose from the timing cover directly to the side of the HIF44, that is all. The rocker cover oil filler cap must be the vented type. So long as the canister on the timing cover is not blocked, it should all work pretty well, but rarely perfectly - it should be the odd drip, not a 'slick'!

None of the 1275 engines ever had an OEM breather hose connected to the rocker cover - we have been here before. The last rocker cover breather connection was on the the early 1098 engines, before they went to the hose from the front tappet cover to inlet manifold PCV.

Interestingly when I fitted a timing belt conversion to our 1380, it only had a very small hole in the breather connection to HIF carburettor, and both oil consumption and leaks increased. After removing it and reverting to the standard duplex chain and timing cover separator/breather, both went back to where they were before, ~1,000 miles per litre and the odd drip from the rear scroll.

[bmcecosse]

The rocker breather being dropped from the 1275 engine is the biggest mystery of all time..... 1275 S Mini engines DID have that breather and it worked well enough on them. I always use a rocker breather - can't see why not! The vented oil cap leaks carcinogenic fume and oil mist if there is any 'heavy breathing' going on - perhaps only at high revs/working hard - but can make for a smelly engine and a messy rocker cover........

[IslipMinor]

The whole point of the closed circuit crankcase ventilation system is that it continually draws air IN through the filler cap, down through the crankcase and up into the carburettor inlet tract and out through the exhaust. If there is any sign of fumes or oil around the rocker cover breather, it is because the the system is not working properly.

Our 1380 works very hard, quite often, and we have never had a hint of fumes or oil around the vented cap.

Fitting a vented cap to the original 'open' system can cause problems, it should be the non-vented type.

[bmcecosse]

Oh yes - the closed circuit vent system is the best. And should cope well if the engine is in good condition. But if not - it can get smelly and messy very quickly....

[jaguar68]

Richard,

I was mistaken about the breather hoses (the joys of working from memory)

Connected to the carb is the vacuum advance from the distributor and the can type breather from the timing cover. This has been modified at some time and moved from the front of the engine to the rear of the front engine plate.

I'm not sure what type of filler cap is fitted, vented or not, as they were all bits kicking around the garage, as the engine was originally fitted with an awful alloy rocker cover.

I'm pretty sure I have a vented rocker cover somewhere and will try this along with a new filler cap and hoses.

If I could get the leak down to a couple of drips per 1000 miles I'd be happy. At the moment it looks as thought the Torrey Canyon has dumped its cargo on the road outside the house, a little embarrassing, as you can imagine!!

Regards

John

[bmcecosse]

Is the oil leaking from in front of the engine backplate (ie the sump seal) or from behind the backplate and/or dripping from the jiggle pin (ie the rear oil labyrinth 'seal')? I've heard of that 'can' being fitted as you describe - depends how it has been fitted as to how easy it will be to remove and clean out.

[jaguar68]

Hi Roy,

The oil is leaking from the front of the engine plate. I've jiggled the jiggle pin in the gearbox bellhousing and can confirm that the leak isn't from there. It could be that the sump seals need replacing. I've nipped up the sump plug as far as I dare, this time replacing the plug washer with the correct copper washer and not the ill fitting nylon one that the engine came with.

I've managed to dig out a rocker cover with a breather pipe. Do I need to use a vented or non vented cap? Also, is it possible to run the rocker cover breather to atmosphere or does it need to be fed into the carb?

Regards

John

[bmcecosse]

So - your leak is from the sump seal, not the rear seal. New sump seals should fix it! I would fit the rocker cover and joiun the breathers with a T - but as Richard says - it's a good idea to draw air through the crankcase, so by all means try a vented cap (although I wouldn't). The rocker breather should not be run to fresh air - but I would try that with the 'can' breather to see if any fume etc came out.