Engine Breathing 1969 1098cc

[svenedin]

I've searched the forum and I know that engine breathing has been discussed at length before but I can't find the answers to my questions so I hope someone can help. I admit that I don't fully understand the topic.

I have a 1969 convertible that I have had for 25 years. Unfortunately, it has not been on the road for nearly 20 years but I am now bringing it back to life (there's a post in the restoration section).

It has an engine that has an "1100" tag on it near the bottom on the right hand side (as viewed from the front). I don't know whether this is the original engine or not. It is obviously an "A" series but it is a bit different to the engine in my first Moggie which was 1965.

My questions relate to engine breathing and also a mystery bracket. This engine has a breather pipe coming from the tappet chest. It looks something like a chimney and the pipe from this chimney joins the base plate of the air filter. There is no rocker cover breather and the oil filler cap is solid. Although this car has not been on the road for a long time I remember that it used to leak oil from the crankcase rear oil seal and suffer from the mayonnaise problem. Is it likely that the breather pipe is clogged up and is it worth me cleaning it out? Might it reduce the oil leak?

The next issue is that there is a blanked off pipe from the inlet manifold. What is this for?

I have a solid oil filler cap. Is that correct?

Lastly (I do apologise for the rubbish pictures) I have noticed a strange bracket under the carburettor. It has a short cylindrical piece of metal on it, help in with a split pin and a hole through it. What is this for? PS I know the choke cable is not fitted correctly, I will sort that out. The part is on the right of the carburettor in the picture, oily and the hole through it can be seen. In fact this is below the carburettor and I cannot work out what it is for.

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[LUR759H]

Hi I dont know much but here is a picture of mine it might give you some ideas.... I had an oil leek from that side breather I simply bought a new gasket and I hope it has solved the problem Ill find out when i finish re welding the side inner wing and the rest of the engine bay...

Kind regards

Alan[frame][/frame]

[LUR759H]

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[philthehill]

The blanked off hole in the manifold is for the Pollution Control Valve (PCV) (PT No: 13H5191).

The item under the carb is trunnion throttle cable Pt No: ACA5280 and is fitted to bracket Pt No: ACA5123 or ACA5378 (dependent upon car chassis number). The bracket fits behind no 5 manifold nut.
See Moss pdf downloadable spares list page 30 for the details of how the throttle linkage fits together.

[bmcecosse]

As Phil points out - your PCV is missing! It is the best breathing system - and without it your engine WILL leak oil in it's present configuration. A slightly crude alternative is to clear that hole and fit a restrictor with a 1/8" hole - and connect that to your side breather pipe - I would also fit a rocker cover WITH a breather pipe and T piece the two together into the restricted pipe in the manifold. And keep the solid cap.... Leaky cap just makes for nasty smells and oily rocker cover.....

[svenedin]

Thank you for your replies.

So the pollution control valve is missing from the blanked off pipe. I have found a picture of the valve and presume one end connects to a pipe on the inlet manifold but what happens after that? Does the PCV connect to somewhere else as well? Does it just flap about in the pipework or is the PCV mounted to something? I also found reference to a Y piece but I don't know what it is for.

I found the picture of the throttle trunion in the Moss catalogue but I am still confused. My throttle cable goes into a bracket near the rocker cover at the moment (see first picture of my original post) so it operates from the top rather than the bottom.

Do I have the wrong rocker cover? Both the lack of a rocker cover breather and the throttle linkage make me thing something has been modified.

Sorry for all the questions but I can't find a diagram or picture of what my set up should look like and I don't want to order the wrong parts or mess it up in some other way!

Best Wishes,

Stephen

[svenedin]

I also wanted to mention that if I connect the side breather pipe to the (currently missing) PCV (as suggested by Bmcecosse) then what will go to my air filter? The present arrangement is that the side breather pipe connects to a spigot on the air filter baseplate (i.e it is different to a standard air filter base). I'm just trying to establish what is supposed to be connected to what and how.

Is the correct arrangement a pipe from side breather to air filter (as now) and a pipe from rocker cover to PCV or is it something else? The current rocker cover does not have a breather outlet. I thought that crankcase fumes were usually directed to the intake manifold to get rid of them and maintain negative pressure but that there needs to be a source of air into the engine as well?

[philthehill]

The pipe that comes from the oil canister/defuser attaches to the PCV.
There should be NO pipe from the rocker cover to the air cleaner. The set up i.e. carb and air cleaner IS NOT ORIGINAL so it is a bit of a mix and match. So long as the pipe is to the PCV and you have a NON vented oil filler cap all will be OK. Do not worry about the air cleaner.
There is/should be a steady bracket between the PCV and the manifold and it looks as if you are using it for the end of the throttle cable and not the proper bracket.
You have the correct rocker cover for the sealed breathing system.

[svenedin]

Phil. Thank you. That clears up my muddle. It is so confusing coming back to my car after 20 years when I didn't know how it was supposed to work in the first place!

[philthehill]

As regards the throttle cable and the bracket just fit the bracket and run the cable though the trunnion to the carb throttle lever and all should be OK.
As I said your set up is a bit of a mix and match so you will have to use what you have got.
The Moss parts list shows a H2 SU carb and you have a HS2 SU carb fitted but the principles and fitments for throttle operation are virtually the same.

[svenedin]

Thanks. The bracket and trunion for the throttle cable are in place it's just that the throttle cable isn't routed this way at the moment. I will correct this in due course but I am in the Alps at the moment. As to having a bit of a mixture of parts I can't remember why this is. I certainly bought the car 25 years ago without the correct breather set up, with the PCV pipe deliberately blanked off and with the throttle cable incorrectly routed. It isn't my fiddling with that. What might be my fiddling (but I can't remember) is switching the carb on the car for one I overhauled after someone gave me it. The intention was to overhaul the original carb as well but I didn't get round to it. I have another complete carb and float chamber which is older. The current carb on the car has the non-adjustable float. The one of my shelf is the earlier adjustable type. I know this because the float needle was stuck fast and incidentally so is the jet (so that the choke lever can't push out the jet). I used my carb on the shelf to remind me how it all works.

[philthehill]

The manifold and carb are matched so no problems there.
Over the years parts get changed so again no problem with having a HS2 carb and PCV manifold.
The main thing is to get it all working and interacting correctly.
You would not want to work on my Minor which is a complete mix and match of BMC parts.

[bmcecosse]

Although the standard set-up may not have had a breather rocker cover - I would fit one - and connect both breathers to the PCV valve with the Y piece you mention! Can't have too many breathers...and NO NEED to let any 'air' in to the engine if using the PCV valve. Your problem may be finding a suitable PCV valve now...

[philthehill]

The PCV valve is available from Mini Spares (Pt No: 13H5191) @ £42.41 inc VAT.
You could try and find a S/H one but check the diaphragm (Pt No: 27H7758) for splits; again available from Mini Spares @ £5.40 inc Vat.
The 'Y' piece (Pt No: 12G2134) is also available from Mini Spares @ £3.92 inc VAT.
The bracket between PCV and manifold (Pt No: 12G609) is available from Somerford Mini @ £2.22 inc VAT.

[bmcecosse]

That price is amazing... there are plenty of less expensive PCV valves on ebay - whether they are adaptable for use on your engine would be up to you to work out..

[philthehill]

bmc
The PCV fitted to BMC/BL vehicles valves all have the same part number.
I have exactly the same valve on my 2.25 ltr Ser 3 Landrover. In this case size does not matter
The bracket on 'e' bay is £7.95

[svenedin]

Thanks for the guidance on where to get the parts. I will order the PCV and some new hose and see how it goes. I think the bracket for the PCV is already there with the throttle cable incorrectly routed through it. Once this set up is working I might try to find a rocker cover with breather pipe and connect that up as well with the Y piece.

[philthehill]

Before you rush out and buy a PCV at great cost - there is one NOS PCV on 'e' bay item No: 121416438800 @ £40 Buy It Now price.

[bmcecosse]

Is it complete though???

[philthehill]

It appears to be complete and in its BMC box/wrapping.
Post is a bit steep though but it does have an offer option.