MGB GT Oil Vapour from Breather Pipe
Discussion
I have just bought a 1977 MGB GT and on the run home I noticed what appeared to be steam coming from under the bonnett when I pulled in for some petrol. When I got home I saw it was actually oil vapour coming out of the breather pipe on the side of the engine also when I took the oil filler cap off I could feel a slight puffing and the vapour from the breather seemed to be less. Can anyone point me in the right direction to solve the problem?
firstly if you haven't already got a copy invest in a copy of the reprint of the original factory Driver's Handbook (this is not a workshop manual) as this will tell you so much of what you need to know as an owner - (Ref: 0053) - http://www.mgocshop.co.uk/catalog/Online_Catalogue...
check to see if the vent pipes/hoses are blocked, that the pipes are plumbed correctly, that the oil filler cap is of the correct type
if you put a good photo up of the engine bay this will to see if things are as they should be
if you have oil leaks this might (or might not) be a sign of the vent pipes being blocked or plumbed in wrong
I always suggest with a classic new to you that you carry out, and it's not as much as it sounds, a full and proper 36k-mile service for the whole car, this can be done in stages but the sooner it's done the better and quicker you pick up on other actual and potential wrinkles and prevent potential wrinkles
Driver's Handbook lists full servicing schedule and what's involved
the other side to achieving as much as possible a reliable and trouble free ownership is to regularly drive the car in all weathers to get used to the car and find out it’s full capabilities and you’ll learn to drive it properly
ETA: if the car hasn't been moved for a while it might be nothing other than a sign of other stuff to check as laying-up cars brings 'wrinkles'
check to see if the vent pipes/hoses are blocked, that the pipes are plumbed correctly, that the oil filler cap is of the correct type
if you put a good photo up of the engine bay this will to see if things are as they should be
if you have oil leaks this might (or might not) be a sign of the vent pipes being blocked or plumbed in wrong
I always suggest with a classic new to you that you carry out, and it's not as much as it sounds, a full and proper 36k-mile service for the whole car, this can be done in stages but the sooner it's done the better and quicker you pick up on other actual and potential wrinkles and prevent potential wrinkles
Driver's Handbook lists full servicing schedule and what's involved
the other side to achieving as much as possible a reliable and trouble free ownership is to regularly drive the car in all weathers to get used to the car and find out it’s full capabilities and you’ll learn to drive it properly
ETA: if the car hasn't been moved for a while it might be nothing other than a sign of other stuff to check as laying-up cars brings 'wrinkles'
Edited by nta16 on Friday 19th July 21:40
Good idea to get a reprint of the original factory Workshop Manual, check it covers 1977 cars, Haynes manuals usually have some errors or omissions
you can also get free parts catalogues but they also can contain errors or omissions so a reprint copy of the original factory Parts Catalogue can be very useful and you can see what goes where
I prefer paper copies as I find them much more convenient but you can get a less convenient electronic versions on a DVD with all three publication on – http://www.rimmerbros.co.uk/Item--i-HMCC3007DVD
please bear in mind the engine is never a very important component on a car much more important are the brake, suspension and steering systems
tyres are often overlooked on classics as they appear to have plenty of tread depth but that’s not the full story with tyres
with respect to you most classic car owners even long term owners don’t know just how well their cars should and could go they buy into the it’s old so it’s pretty slow, doesn’t handle that well and is unreliable – just looking after them properly and actual using them to transform the car’s performance
ETA: more information and some entirely different views to mine on the MG BBS
you can also get free parts catalogues but they also can contain errors or omissions so a reprint copy of the original factory Parts Catalogue can be very useful and you can see what goes where
I prefer paper copies as I find them much more convenient but you can get a less convenient electronic versions on a DVD with all three publication on – http://www.rimmerbros.co.uk/Item--i-HMCC3007DVD
please bear in mind the engine is never a very important component on a car much more important are the brake, suspension and steering systems
tyres are often overlooked on classics as they appear to have plenty of tread depth but that’s not the full story with tyres
with respect to you most classic car owners even long term owners don’t know just how well their cars should and could go they buy into the it’s old so it’s pretty slow, doesn’t handle that well and is unreliable – just looking after them properly and actual using them to transform the car’s performance
ETA: more information and some entirely different views to mine on the MG BBS
Edited by na on Saturday 18th February 14:42
also of great help can be the John Twist videos - they're about US cars but most still applies and the principles apply even when he's talking about different models (and rarely different make)
this video tells you about oil loss and is well worth watching the whole way through
and the end of this video is a bit that is particularly relevant to your post here, there is another video that covers the venting I'll see if I can find it, but for now have this - http://www.youtube.com/user/Universitymotorsltd#p/...
this video tells you about oil loss and is well worth watching the whole way through
and the end of this video is a bit that is particularly relevant to your post here, there is another video that covers the venting I'll see if I can find it, but for now have this - http://www.youtube.com/user/Universitymotorsltd#p/...
The breather pipes connect to each SU carb and come from a pipe coming out of the tappet chest underneath the left hand carb. Either they have come adrift or withered with age.
A parts manual will come in handy together with a Haynes manual, MG International used to be the parts list to have, long gone but I'm sure there's others online now B&G for one.
HTH
Saxx
A parts manual will come in handy together with a Haynes manual, MG International used to be the parts list to have, long gone but I'm sure there's others online now B&G for one.
HTH
Saxx
saxxeblt said:
The breather pipes connect to each SU carb and come from a pipe coming out of the tappet chest underneath the left hand carb. Either they have come adrift or withered with age.
and/or blocked or see videosaxxeblt said:
A parts manual will come in handy together with a Haynes manual, MG International used to be the parts list to have, long gone but I'm sure there's others online now B&G for one.
HTH
Saxx
I'm not disagrreing with you just expandingHTH
Saxx
I always put workshop manuals for repairs but Driver's Handbook for prevention
Haynes are OK but I find it covers both ends of the knowledge spectrum but not so much in the middle, a reprint of the original factory Workshop Manual is available, I've no idea how well it covers the later cars though
neither of my two copies of Haynes really cover my year of car despite both claiming to
as for free suppliers parts lists I've found they contain errors and omissions and if you conpare them against each other you can get different answers, I use the reprint of the original factory Parts Catalogue for the start as I've only ever seen a couple of errors in the drawings (they may be many more but not that I've used) and then compare two or three suppliers against it to see what is available now
as I put above all three publications are available on one DVD
Edited by na on Saturday 18th February 21:45
Hi a further update the breather pipe from the small panel at the side of the engine just hangs free I believe it should attach to a Y piece that feeds into the inlet manifold on the SU carbs. I have done a compression test and No. 1 cyl. is 130 PSI the other 3 are 118 PSI these I believe are quite low so think this is why oil vapour is coming from the breather pipe and if I were to connect it to a Y piece on the carbs I would expect smoke from the exhaust. Will do a bit more investigation but think I will probably have to either replace engine or fix the one I have.
You don’t say if you’ve got plumes of blue smoke coming out of the exhaust or what oil pressure you’ve got? ie. low oil pressure when on the move.
If the above is not an issue, you might just need a de-coke. Take the head off clean the valves up and re-grind and put a new head gasket on and new valve seals etc.
You could find doing that restores your compression on all cylinders.
The breather pipes you are concerned about are just that, they allow the crankcase to breath and not build up pressure as the crank turns, they vent to the SU’s
Hope this helps.
Saxx
If the above is not an issue, you might just need a de-coke. Take the head off clean the valves up and re-grind and put a new head gasket on and new valve seals etc.
You could find doing that restores your compression on all cylinders.
The breather pipes you are concerned about are just that, they allow the crankcase to breath and not build up pressure as the crank turns, they vent to the SU’s
Hope this helps.
Saxx
What he hasn't actually said is if there is anything actually wrong with the engine!
B engines like to breathe, the breather should be connected to the carbs, connect it up properly and just enjoy the car, if it's pouring smoke out of the back end or knocking it's t**s off then consider doing work on the engine otherwise just enjoy it, B engines don't need mollycoddling just regular oil changes and keeping in good running order.
B engines like to breathe, the breather should be connected to the carbs, connect it up properly and just enjoy the car, if it's pouring smoke out of the back end or knocking it's t**s off then consider doing work on the engine otherwise just enjoy it, B engines don't need mollycoddling just regular oil changes and keeping in good running order.
reconnect breather pipes and enjoy - as WO's put the engine will appreciate oil & filter changes and clean carbs and air filters
anyway the engine not that important compared with things like brakes, steering, suspension, tyres, ect.
the car will get better the more you drive it regularly, if only because you'll be getting used to it driving it and you'll dbe iscovering any of it's wrinkles with use
I still strongly suggest getting the Driver's Handbook so that you know all about your car as you would with a brand new car
I'd also strongly suggest you at least use a 36k-mile service as a checklist over the car to help spot and rectify potential problems and possible breakdowns and roadside repairs which usually happen at the least convenient times
classic cars don't have to be slow, poor handling, thirsty, leaky and unreliable but a lot of previous (and present) owners do make them and keep them that way
that's me finished, enjoyed your BGT
anyway the engine not that important compared with things like brakes, steering, suspension, tyres, ect.
the car will get better the more you drive it regularly, if only because you'll be getting used to it driving it and you'll dbe iscovering any of it's wrinkles with use
I still strongly suggest getting the Driver's Handbook so that you know all about your car as you would with a brand new car
I'd also strongly suggest you at least use a 36k-mile service as a checklist over the car to help spot and rectify potential problems and possible breakdowns and roadside repairs which usually happen at the least convenient times
classic cars don't have to be slow, poor handling, thirsty, leaky and unreliable but a lot of previous (and present) owners do make them and keep them that way
that's me finished, enjoyed your BGT
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