Oil leak from the back of the engine

Post by **dougieboard** » Mon Mar 09, 2009 5:58 pm

Hello,

Sorry if this is very obvious or has been covered endlessly.

I have a reasonably bad leak from the back of the engine of my 1969 1000 saloon.

I have a vague recollection of reading that there is no oil seal as such, and it is scroll seal of some sort and that a leak is likely to be caused by a blocked breather.

Is that right? The breathing apparatus is so primitive that it doesn't seem that likely. My engine has a breather on the side cover which runs up to the air filter. There is no breather from the rocker cover.

How can i check the engine breathing, and how can I clean the 'thing' attached to the side cover. Can I just pour petrol through it, or soak it?

Cheers in anticipation

Nigel D

Post by **Peetee** » Mon Mar 09, 2009 6:49 pm

Dont assume it is the crank seal. I thought just this and found it was the gasket on the end of the oil pump that had failed.
With the engine out this is a fairly simple job to replace.

As far as the breather is concerned, before removing the engine I ran it with some engine flush and then poured some parafin down into the breather to clear it out.

I now have a 1275 A+ engine that does not leak at all. Well chuffed is I.

Post by **dougieboard** » Mon Mar 09, 2009 9:23 pm

Cheers for the quick response.

I've had a lot of oil leak problems with the side cover vent over the years, but I've never actually cleaned it out. Job for the weekend I reckon.

And I don't think I've ever owned an A-series engined car which doesn't spot a bit of oil. Well done on that oil-tight A+!

Post by **Peetee** » Mon Mar 09, 2009 10:06 pm

Well done on that oil-tight A+!

A lucky find. It was sat in a car that was beyond saving. I was honest with the owner about the state of the body and it was just a case of subtley suggesting that, finacially speaking, his engine would be better off in my mog.

Post by **dougieboard** » Mon Mar 09, 2009 10:24 pm

Always a delicate conversation - I once parted with a very, very rough Traveller and the bloke didn't want to admit that it was going to be bag of bits by that evening. Thing is, I didn't want it, so I could hardly kick off if someone else was going to get some use out it...

Post by **bmcecosse** » Tue Mar 10, 2009 2:35 pm

You would do better to find a rocker cover WITH a breather pipe and fit it. The engine really needs two breathers - the one on the side cover to let air in/excess fume out - the one on the rocker cover should be connected to the air inlet system - later carbs have a wee brass connection on the side for this, which is ideal. The connection to the air filter casing just spreads oil all over the paper air filter - which is NOT ideal!

Post by **PSL184** » Tue Mar 10, 2009 5:57 pm

You can drill the sandwich plate between carb and manifold to take a spigot which will then take the pipe from the rocker - best place for the fumes from the breather is directly back into the engine....

Post by **bmcecosse** » Tue Mar 10, 2009 7:32 pm

And NOT into your lungs ! The fumes MUST be extracted into the engine - otherwise in can be eye-watering and v sore throat inducing - and probably long term v damaging to the lungs! Been there - done that - on competition engines. All night rally breathing these fumes - we were both v unwell for several days afterwards. And no - it wasn't exhaust fumes - the system was all good and the tail pipe was well out the back of the car!

Post by **dougieboard** » Tue Mar 10, 2009 11:37 pm

This is the view of the manifold side of the engine with the breather shown bottom of the pic near the centre - the hose has been removed for the photo along with the air cleaner it attaches to - the alloy rocker cover replaced a standard pressed steel one with no breather, but there is some sort of take off on the manifold which has been blocked off. Could any part of this arrangement being contributing to the oil leak? It has been set up this way since I got the car in 1993

All contributions welcomed...<br>

<br>

Post by **dougieboard** » Tue Mar 10, 2009 11:38 pm

And now you mention it, air filter is always pretty oily...

Post by **bmcecosse** » Wed Mar 11, 2009 8:38 am

Yes - someone has fitted an after market rocker cover (may be ex MG Metro) with no breather. That's the problem! Maybe you could drill/tap fit a breather to it - or just look for an early rocker cover with breather. Air filter covered in oil is useless - will choke the engine and make it run rich - with poor top-end performance as it struggles for air.

Post by **dougieboard** » Wed Mar 11, 2009 9:49 am

Cheers for the advice.

One thing though. If I do that, presumably that will hook up to the air cleaner. What do I connect the breather on the side of the engine to? If it just goes to the atmosphere, won't that cover the engine bay in oil?

Post by **wibble_puppy** » Wed Mar 11, 2009 1:45 pm

If the rocker covers are supposed to have breather pipes, why were some A series engines made with rocker covers which don't have breathers? (Mine was.)

Post by **alex_holden** » Wed Mar 11, 2009 1:59 pm

My understanding is:

Early engines have a swan-neck breather pipe on the tappet chest pointing towards the road, a sealed oil filler cap, and fumes are drawn out from a pipe on the rocker cover to a fitting on the air filter housing.

Late engines have a vented oil filler cap, no pipe on the rocker cover, and fumes are drawn out through a chimney-like oil separator on the tappet chest to a fitting on the side of the carb.

Nigel's car has the late-style oil separator on the tappet chest so I think it should also have a vented filler cap and no pipe on the rocker cover.

Post by **dougieboard** » Wed Mar 11, 2009 2:00 pm

wibble_puppy,

Does yours have a breather on the side of the engine like mine?

Post by **wibble_puppy** » Wed Mar 11, 2009 2:15 pm

dougieboard wrote:wibble_puppy,

Does yours have a breather on the side of the engine like mine?

Yes - although it's on the rear tappet chest cover rather than the front one, for reasons unknown (or unremembered by me - Holden might remember). It also has a vented oil filler cap.

Post by **alex_holden** » Wed Mar 11, 2009 3:37 pm

wibble_puppy wrote:Yes - although it's on the rear tappet chest cover rather than the front one, for reasons unknown (or unremembered by me - Holden might remember).

It's welded at different angle and the oil catcher clashes with something (can't remember what) if you try to fit it to the front tappet chest.

Post by **bmcecosse** » Wed Mar 11, 2009 4:58 pm

All will perform better with a proper vent pipe taken from the rocker cover. The 'vented cap' can make for a smelly engine - and sore throat etc on a long run !

Post by **PSL184** » Wed Mar 11, 2009 5:10 pm

dougieboard wrote: won't that cover the engine bay in oil?

No, your engine shouldn't be pumping oil out of the breather - Just fumes!

The changes to the breather system came into force as emissions regs were tightened. It was felt that an engine eating it own fumes would increase the emissions and hence fail to meet the new regs that were introduced. Solution (?) was to remove rocker cover breather and fit a vented cap. However, this now relies on the chimney providing almost all the breathing so if this gets clogged up the engine can't breath properly and looses the negative crankcase pressure which holds the oil in. As pressure increases the weakest seals allow the oil past them (usually rear crank seal). The vented cap is also a service item and should be changed every 10,000 miles as this also clogs up easily.....

Post by **dougieboard** » Wed Mar 11, 2009 5:37 pm

Sorry PSL,

I meant 'film of oil' - just like I get in the air filter.

Thing is, I'm not sure the aly rocker cover has a vented cap, and if that is the case, it would explain the pressurisation?

Great info though, so thanks all