Engine breather

[Vernon]

My recently purchased Traveller had a serious oil leak. So far I have replaced the rocker cover gasket and rubber grommets but I am uncertain about the crankcase breathing system. I know that the rocker cover and oil filler cap are non standard but the cap has a pin hole vent. The engine No. is 10V/189E/H54151. Can someone tell me if the breather connections shown in the photo are OK or could this cause oil leak problems.[frame][/frame]

[panky]

The vent should be connected to the vac connection on the side of the carb, ideally using a PCV but not essential.



The air filter and carb shown is obviously not standard but you carb should still have the vacuum connection.

[bmcecosse]

As above - the PCV is highly recommended - and connected to the carb - no use going to the air fiter. However the PCV shown above is not connected correctly - the PCV should be on the inlet manifold - and then connected to the breather system. You would be wise meantime to get a rocker cover with breather pipe - and connect that also the carb side vent. If it doesn't have one - then look for an HS2 carb with side vent. Where is the oil leak coming from ? The jiggle pin under the gearbox bell-housing?

[Vernon]

I can't see a vent on the carb except the connection to the vacuum advance/retard on the distributor. Does this mean I need a new carb and a new rocker cover and a PCV? On my previous car with a 10MA engine the breather pipe on the rocker cover was connected to the air filter.

[panky]

Sorry to correct you Roy but this type of PCV can only be fitted in this way. It's a dead-weight valve and has to be in the upright position to work - and it works in the direction it is fitted on my car, originally they would have been fitted to the rocker cover of the vehicle they where designed for.



Not having a suitable connection on the rocker cover I thought the second best place was the 'chimney'.

[POMMReg]

Sorry to correct you Roy but this type of PCV can only be fitted in this way. It's a dead-weight valve and has to be in the upright position to work - and it works in the direction it is fitted on my car, originally they would have been fitted to the rocker cover of the vehicle they where designed for.



Not having a suitable connection on the rocker cover I thought the second best place was the 'chimney'.

Oooh, an SJ......fantastic things...

[panky]

I think it's a Jeep Wrangler, same one's fitted to a Jeep Cherokee

[Vernon]

I can't see a vent on the carb except the connection to the vacuum advance/retard on the distributor. Does this mean I need a new carb and a new rocker cover and a PCV? On my previous car with a 10MA engine the breather pipe on the rocker cover was connected to the air filter.

If the breather is "no use going to the air filter" how can I improve things without going to the expense of getting a new carb?

[panky]

You will need to check if the oil leaks are actually cause by poor crankcase ventilation, where is the oil coming from? If it's a leak from the side covers or sump gasket a better breather wont cure that I'm afraid

[philthehill]

Check that the canister breather/oil separator is clear and able to pass fumes before doing anything else. They do get blocked up and the bottom of the canister has a tendency to rot out as the condensate cannot drain away from the bottom of the canister.
Pictured is the crud removed from a blocked breather/oil separator canister.[frame][/frame]

[bmcecosse]

I'm very surprised - the PCV usually works on the inlet manifold - that's the idea of the thing. Can't see the point of it when fitted your way.. I would have thought that 1098 engine would have a carb with vent pipe. Problem with the air filter connection is that a) it splatters oil all over the filter - blocking it, and b) very much reduced suction there compared to the carb connection.

[panky]

The type normally fitted to Minis are and this one works in a similar way - the flow of fumes is still from the engine to the inlet manifold it's just positioned differently. As you said all modern engines have them and this one is off a modern engine.

[bmcecosse]

Yes - but the idea is to have good suction in to the inlet manifold, without affecting idling too much. . The way yours is connected it's not doing anything useful.

[panky]

I think I understand you mean, the drilling on the vac connection to the carb is not always open unless the throttle butterfly is operated - and yes it would work better on a connection downstream of the carb, this is something I will address when I fit an alloy manifold in the near future.

[Vernon]

Thanks to all who have replied.

So, firstly I need to clean out the breather/oil separator canister and replace the wire wool (with metal pot scourer?) and then I plan to connect it to the inlet manifold via a 1/8" restrictor. Will this give me the required negative pressure to avoid oil leaks?

[philthehill]

So long as you have good crank case ventilation - venting to atmosphere is more than adequate for an engine in good condition.
Having negative pressure in the crankcase will be and is of real benefit to an engine that has piston ring blow past.
As emission controls became tighter BMC tried to reduce the effects of crank case piston blow past by having the fumes sucked out of the crankcase by the low pressure generated in the inlet manifold - then the fumes passed through the inlet manifold to the combustion chamber where they were consumed. Or so the theory goes.

[Vernon]

So long as you have good crank case ventilation - venting to atmosphere is more than adequate for an engine in good condition.

So now I'm thinking it might be easier to get a tappet chest cover with the vent pipe to air down the side of the engine and a rocker cover with a vent pipe to connect to the air filter as they used to be.
Has anyone got a tappet chest cover and rocker cover to sell?

[philthehill]

Vernon
If it was my engine I would want to make sure that what I have is working as it should be i.e. the canister oil separator is not blocked and is free to pass air/fumes through it.
It is not hard to get the gauze out of the canister but make sure that you get every little bit out as you do not want any crud falling back into the sump.
There are two clips which hold the gauze in place and if careful you can get them both out.
If you find that they are rusted out they are only made from small dia mild steel round wire and replacements can be easily made from welding rod or similar.
I purchased some stainless steel pan scrubs to go inside the canister.
The original gauze is made up of endless mild steel strip turned off a round bar and is made in exactly the same way as the pan scrubs but which of course are turned off a stainless steel round bar.
Fit the pan scrub into the canister and fit the bottom clip.
The top clip is not so important as the pan scrub cannot come out of the top hole.
Phil[frame][/frame]