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breather? Smells?
Posted: Thu May 10, 2012 11:02 am
by JaneHibbert
Okay, okay, I'm finding the basics difficult, but trying! I have been reading posts on here all morning trying to find out about smells and breathers
My 71 Minor has the following set up - it has a pipe coming out of the side of the engine, lower down at the front with a 'tin can' on, this has a pipe going to the air filter housing (NOT the carb, but the air filter). I'm presuming this is the crankcase breather I have read about? It seems to have no other breathers anywhere, the rocker cover is blank. The oil cap, though, seems to be of the vented type. So my question is, is this normal?
Why I ask is the whole engine bay, and the inside of the car is really smelly all the time like dirty oil fumes.
Thanks guys for any help
Re: breather? Smells?
Posted: Thu May 10, 2012 11:28 am
by JaneHibbert
Oh, and when I open the oil cap there always seems to be a bit of mayo on it and a whisp of fumes if it has been running. Don't know if that helps?
Re: breather? Smells?
Posted: Thu May 10, 2012 11:35 am
by JaneHibbert
Oh, and also could somebosy explain REALLY SIMPLY what the breather system should be and what it does? Thanks guys.
Re: breather? Smells?
Posted: Thu May 10, 2012 12:56 pm
by mike.perry
The crankcase breather should vent the excess pressure which builds up in the sump and is caused by the pistons pumping up and down. On earlier engines this was achieved by simply having a breather pipe on the side of the engine which vented the air and hopefully the smelly fumes under the car. Later this was improved by having a breather pipe on the rocker box which vented fumes from the top of the engine in to the air filter, resulting in an oily clogged up air filter. The next system was to have a cannister to catch the oil and a breather pipe attached to the carb which sucked the air out of the sump.
Re: breather? Smells?
Posted: Thu May 10, 2012 1:06 pm
by JaneHibbert

thanks!
So I have a latter canister only, no rocker breather - as seems right from what you say, but mine attaches to the airfilter housing, not the carb? Is that a problem... Can I clean the canister out?
Re: breather? Smells?
Posted: Thu May 10, 2012 1:09 pm
by bmcecosse
It's smelly (and these fumes are carcinogenic) because of the silly vented cap.......... But also - the breather hose is not taking away the fumes sufficiently - and if you look inside the air cleaner I expect the paper element will be covered/choked with oily filth... The fumes may be excessive because of general wear/tear - or because the breather hose is blocked/choked. It would be FAR better to get a rocker cover with breather connection - and a carb with the inlet pipe for the fumes. Then connect the rocker cover to the carb, and let the breather hose from the can vent out below the car where the fumes will be swept away in the slipstream.... As a check -next time the engine is hot - leave it idling, take the oil filler cap off and rev up. Is there a distinct plume of smoke/fume ??
Re: breather? Smells?
Posted: Thu May 10, 2012 4:48 pm
by JaneHibbert
Carcogenic? God, I didn't think it would be that bad! I went for a drive until it was hot, then did as you said - there was a few whisps of fumes when I took the vented cap off (THERE WAS NEW MAYO STUFF) , but when I revved it there was nothing else... neither was there any noticable stuff coming out of the lower breather pipe? Can you clean out the lower canister, it seems an impossible task?!
Getting a new rocker cover with a vent then, that should be easy, could I just attach it to the air filter for now (that has no gunk on / in it at the moment) as per the other breather? Then run the tappet breather under the car? Then I presume I'd get a none vented cap for the top?
As for the carb thing, bit afraid of such mejor things at the moment, would that be expensive?
Re: breather? Smells?
Posted: Thu May 10, 2012 5:56 pm
by JaneHibbert
God, just took the rocker cover off and the whole top inside is covered in mayo!
Re: breather? Smells?
Posted: Thu May 10, 2012 6:12 pm
by tomas.geoghegan
Hi i Hope its not the head gasket.
Tomas
Re: breather? Smells?
Posted: Thu May 10, 2012 6:51 pm
by JaneHibbert
And me, but oil looks totally normal, and waterlevel fine. I think it simply hasn't been breathing properly... would that have caused the build up?
Re: breather? Smells?
Posted: Thu May 10, 2012 9:26 pm
by moggiethouable
JaneHibbert wrote:God, just took the rocker cover off and the whole top inside is covered in mayo!
Are you near a local Mog owners club?
I think it would be worthwhile contacting them, because if it needs a new head gasket you may or may not feel this is something you can tackle yourself.(white Mayo may be indicative of oil water mix)
It is not a huge job (ive just changed mine) but I dont know how confident you feel about doing it alone.
Re: breather? Smells?
Posted: Thu May 10, 2012 10:01 pm
by JaneHibbert
Thanks, I'll do that, I'm in Stockport if anybody near? Oh, how can I clear out the tappet breather?? No air pressure coming from it when the engine is going so presume its blocked, but can't work out how to get the 'canister' off?
Re: breather? Smells?
Posted: Thu May 10, 2012 10:05 pm
by bmcecosse
Don't panic - it's not the head gasket, it's just cold running and poor breathing. Clean it all out before refitting! To remove moisture you need to draw air through the engine. The cannister can be cleaned out - remove the cover and wash it through with paraffin - several times probably.... Some Mini lads set the can on fire....not on the engine, obviously I hope.... Yes - connect to air filter will do for now. As the filter was not gunged up - it's safe to assume that the cannister is pretty much blocked - and that's why the fumes are coming out of the filler cap. I would still get rid of it....and get a cover with breather tube.
Re: breather? Smells?
Posted: Thu May 10, 2012 10:35 pm
by JaneHibbert
OH thank you BMCECOSSE, but the canister on the pipe seems all 'fixed' on, does it pull off the engine in some way?
Re: breather? Smells?
Posted: Thu May 10, 2012 11:39 pm
by bmcecosse
The cover with cannister comes away with one bolt....... 1/2" AF ring spanner will do it.
Re: breather? Smells?
Posted: Fri May 11, 2012 3:55 pm
by tomas.geoghegan
Oil and water OK
Thank god for that!
Tomas
Re: breather? Smells?
Posted: Fri May 11, 2012 8:08 pm
by JaneHibbert
Thanks everybody, does anybody know where I can get a working secondhand carb with a breather tube then??
Re: breather? Smells?
Posted: Fri May 11, 2012 8:10 pm
by JaneHibbert
oh what sort of carb do i need for a 71 morris, is there a model number?

Re: breather? Smells?
Posted: Fri May 11, 2012 8:19 pm
by bmcecosse
HS2 - or upgrade to an HS4 with manifold - from a Mini or Metro or Marina
Like this - except the postage is ridiculous......
http://www.ebay.co.uk/itm/Classic-Mini- ... 3375c186bb
Re: breather? Smells?
Posted: Fri May 11, 2012 8:26 pm
by JaneHibbert
Thanks, i just looked in the box of bits i got with the minor and there IS a carb in there with an extra tube than mine at the back of the pot which im presuming is a breather intake - brilliant. but hos do i know if it works? should i try and rebuild it?
supposing it work the best set up then bmcecosse, the rocker cover breather pipe going to the new carb, a solid none venting cap and the bottom tappet breather venting under the car - would it be worthwhile having the tappet breather venting into the carb / air filter as well? Cos i thought having one 'open' might still let fumes into the car?
but i spose the first thing is this old carb? any instructions for testing / rebuilding?
