27 replies to this topic

[Piper x]

Got a bit of an issue here, hoping some of you much better qualified than me can help make a decision on!

I recently had my Mini serviced at a local(ish) Mini specialist, who is regarded as a bit of a guru with all things Mini.

 

I questioned him about the open breathers (arrowed "A" in the pic) and he advised to leave as they are.

However, a couple of people commented on this on the recent Scottish Thistle Run, and stated they should be connected to the breather cans coming from the timing chain case and clutch housing respectively, otherwise she will run like a dog. (The thing is, she can be a bit temperamental at times - and smoky under load, but I thought this was just a Mini "thing") Are these guys right, and this is the reason for the occasional coughing, or should I be listening to the local Mini Meister?

 

The second issue is the tube marked "B". What is this, and should it be connected to anything? It looks like its been capped, (by the Mini specialist) and once again some of the lads on the run commented on this...

 

Thanks as always in advance!!

 

Attached Files

•  inlet.jpg   185.46K   175 downloads

[Alex_B]

Those labelled A are not part of the breather system, those are to run heated water through the inlet to warm the air going into the engine for cold starts, most people leave them off due to them reducing power when the engine is warm,

B should be the fuel overflow pipe, connect to the pipe running down the engine bell housing

[Boomboy77]

Pipes marked A are for the water heated inlet manifold.

In colder climates it can be a good idea to plumb this in to help heat the inlet quicker and maintain an optimum temp.

Although in 18 years of mini-ing, i've never plumbed one in.

 

Pipe marked B is the float chamber over flow, should have a pipe on it going to the floor so any excess fuel coming out of here doesnt ignite on a hot engine!

[Barman]

They are not breathers - they are manifold water cooling connections.

 

You'll find huge arguments on here as to if they should be connected or not.

[Alex_B]

They are not breathers - they are manifold water cooling connections.

 

You'll find huge arguments on here as to if they should be connected or not.

Heating not cooling, and the arguments are nothing compared to which oil to use ;)

Edited by Alex_B, 14 June 2013 - 10:07 AM.

[Skortchio]

A - is your water heating pipe for the inlet, unless your ambient temps are really low for the vast % of the time it's best left unconnected. Doesn't connect to breathers anyway. That's what D.V. says anyhow.

 

B - float bowl vent / overflow, routing it safely clear of the exhaust manifold or into the carbon canister if you have one is suggested.

 

 

Seen there's 3 replies while I've posted (shouldn't have made coffee mid typing) so this is probably redundant now

[jaydee]

You misuderstood whoever told you to connect A to the breathers otherwise it will run like a pig. He was talking about the carb breather that you have blanked off, its close to where you wrote the A in the pic, that has to be connected to the engine breathers if you dont want to breathe all the poisonous engine crap..

The pipe 'B' MUST BE unblocked, if its blocked and you carb is working, that means your carb is worng somewhere (blocked jet probably).

It simply wont work with the float chamber breather disconnected. You have to free it off and connect it to the fuel overflow line, the one running around the clutch wok that exits under the car. Beware that it will need further fixings..

[Barman]

 

They are not breathers - they are manifold water cooling connections.

 

You'll find huge arguments on here as to if they should be connected or not.

Heating not cooling, and the arguments are nothing compared to which oil to use ;)

 

 

And Chinese radiators!

[Piper x]

You misuderstood whoever told you to connect A to the breathers otherwise it will run like a pig. He was talking about the carb breather that you have blanked off, its close to where you wrote the A in the pic, that has to be connected to the engine breathers if you dont want to breathe all the poisonous engine crap..

The pipe 'B' MUST BE unblocked, if its blocked and you carb is working, that means your carb is worng somewhere (blocked jet probably).

It simply wont work with the float chamber breather disconnected. You have to free it off and connect it to the fuel overflow line, the one running around the clutch wok that exits under the car. Beware that it will need further fixings..

Perfect! That will explain why the inside of the car does get a bit unhealthy!! Should both breathers be connected to this?

The posts all commenting on the water inlet on the manifold all make perfect sense to me - I'm sure Id read somewhere before about these!

 

Thanks!

[Cooperman]

All as 'Jaydee' says. It's not worth running cooling water through the manifold as that reduces power at normal operating temp. The inlet charge needs to be as cool as possible.
Also, if you want to stop the breather cans on the timing cover & clutch housing from smoking into the engine bay, you can run hoses from both of them to a catch tank under the LH wing to collect any oil vapour. I use an old plastic 1/2 litre can under the wing mounted on a small bracket and run the pipes into the top.

[Ethel]

I suppose you could run you timing cover breather through the manifold if you had a mind to, for neatness. I'd plumb it in to the cooling system though. Whether it heats, or cools, is relative to the temperatures - what it will do is give more consistency by virtue of the water temp being controlled by the thermostat. That should allow you to achieve better part throttle economy; the impact on maximum power will be minimal because the air will have little time to pick up heat. It's even possible it will be better - the inlet bolts to the head next to the exhaust ports, which can get much hotter than the water in your cooling system.

[tiger99]

Defenition of an expert:

 

Ex = has been

Spurt = drip under pressure

 

So now you know why they disagree!

[Captain Mainwaring]

All as 'Jaydee' says. It's not worth running cooling water through the manifold as that reduces power at normal operating temp. The inlet charge needs to be as cool as possible.
Also, if you want to stop the breather cans on the timing cover & clutch housing from smoking into the engine bay, you can run hoses from both of them to a catch tank under the LH wing to collect any oil vapour. I use an old plastic 1/2 litre can under the wing mounted on a small bracket and run the pipes into the top.

 

It's to prevent icing. The charge is in the manifold for about 0.003 of a second, and it's already chilled going through the choke and vaporizing fuel, I'm not sure it will get measurable hotter.

 

If the carb id running fine with the open vent in it's current "dangerous" condition, then nothing will change if it is piped to a lower, safer location.

[Ethel]

I'm not sure if you're still slightly confused over "breathers". There's little connection between the carb float breather and the engine breathers, other than the word. In your case it just lets the float chamber "sense" atmospheric pressure which gives something reasonably constant for to compare with the suction created above the fuel jet. You can think of the jet and float chamber as a U tube manometer (barometer). If there wasn't a breather the pressure would keep on dropping, as the petrol is sucked into the engine, until the float chamber vacuum became too strong to suck against and fuel starvation occurred.

 

Engine breathers allow the the pressure that would build up in the crankcase from heat expansion and gasses blowing past the piston rings to escape. Motor manufacturers started hooking up the breathers to the induction system to actively suck the fumes out because it recycles the fumes to help reduce pollution. Having crankcase pressure below atmospheric also improves efficiency a little and helps a lot to reduce oil  escaping past the seals.

 

Things can get a bit more complex with emissions control systems that gather fumes from the fuel system along with the engine's or when inlet manifold pressure is used to moderate fuel enrichment (via float chamber pressure) for forced induction or economy.

 

Experts used to say the earth was flat, thinking for yourself is the best way.

[jaydee]

The heated manifold wont do anything for carb icing, it happens in the venturi....