Oil dripping from air filter housing
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- Minor Fan
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Oil dripping from air filter housing
On our 1098cc engine we have a hose from the breather pipe of the rocker cover to the air filter housing. After a run we also have a small amount of oil dripping from the bottom of the air filter housing, presumably having been sucked through the pipe. At an auto-jumble recently they had an original air filter housing like ours but the pipe into the air filter housing was enclosed at the end but with a small hole in it, unlike ours which is 'straight through' with no restriction (see photo). Is this why oil is being sucked in? Should the inlet pipe into the air filter housing be restricted in some way to reduce the chance of oil being sucked in?
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Re: Oil dripping from air filter housing
There is very little suck by the air filter at the breather pipe inlet but you may have plenty of blow from the rocker cover.
What is the condition of the air cleaner in the area of the breather inlet pipe - is it oily?
To check the amount of suck at the air cleaner breather inlet - run the engine at a reasonable amount of revs and placing your finger over the end of the air cleaner breather inlet pipe see what the vacuum feels like.
If little vacuum you have got engine blow by - possibly worn rings, valve guides/seals.
I would fit the later air cleaner with the reduced breather inlet as a matter of course.
BMC did put various restrictors in place to limit engine blow by including a restrictor in the rocker cover breather outlet to limit the amount of oil/fumes exiting the engine.
After various attempts and ways of reducing engine breathing BMC/BL did fit a breather valve and breather pipe direct into the inlet manifold to overcome heavy engine breathing.
What is the condition of the air cleaner in the area of the breather inlet pipe - is it oily?
To check the amount of suck at the air cleaner breather inlet - run the engine at a reasonable amount of revs and placing your finger over the end of the air cleaner breather inlet pipe see what the vacuum feels like.
If little vacuum you have got engine blow by - possibly worn rings, valve guides/seals.
I would fit the later air cleaner with the reduced breather inlet as a matter of course.
BMC did put various restrictors in place to limit engine blow by including a restrictor in the rocker cover breather outlet to limit the amount of oil/fumes exiting the engine.
After various attempts and ways of reducing engine breathing BMC/BL did fit a breather valve and breather pipe direct into the inlet manifold to overcome heavy engine breathing.
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- Minor Fan
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Re: Oil dripping from air filter housing
Can’t answer your question, but here is a picture of hose end you described. Brace yourself it is rusty.
Regards John-
- Minor Fan
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Re: Oil dripping from air filter housing
Thank you John - at least I didn't imagine it.StillGotMy1stCar wrote: ↑Mon Jun 18, 2018 11:17 am Can’t answer your question, but here is a picture of hose end you described. Brace yourself it is rusty.
Air filter housing (640x480).jpg
Regards John
Out of interest how big is the hole? I did think I might make my own restrictor.
Keith
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Re: Oil dripping from air filter housing
No, it isn't oily. The oil just seems to run down the side of the housing and drip out the bottom.philthehill wrote: ↑Mon Jun 18, 2018 11:11 am What is the condition of the air cleaner in the area of the breather inlet pipe - is it oily?
I will check the amount of suck.
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Re: Oil dripping from air filter housing
Sorry for a metric measurement but a 3mm drill bit fits it perfectly.
My engine is the later type that once had the Positive Crankcase Ventilation system fitted but was removed by someone, so not sure it would be of any use if you restrict it. It would most likely start leaking more from the rear crank scroll.
Regards John
My engine is the later type that once had the Positive Crankcase Ventilation system fitted but was removed by someone, so not sure it would be of any use if you restrict it. It would most likely start leaking more from the rear crank scroll.
Regards John
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Re: Oil dripping from air filter housing
Thanks for the sizing. Good point about the oil leaking though.StillGotMy1stCar wrote: ↑Mon Jun 18, 2018 2:47 pm Sorry for a metric measurement but a 3mm drill bit fits it perfectly.
My engine is the later type that once had the Positive Crankcase Ventilation system fitted but was removed by someone, so not sure it would be of any use if you restrict it. It would most likely start leaking more from the rear crank scroll.
Regards John
- geoberni
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Re: Oil dripping from air filter housing
Hi
My Series II was fitted with a 948cc many years ago and I just took a look; it has a Filter housing with the restrictor as in John's photo.
3mm looks about right.
And I wouldn't know what a Positive Crankcase Ventilation system was ...
Berni
My Series II was fitted with a 948cc many years ago and I just took a look; it has a Filter housing with the restrictor as in John's photo.
3mm looks about right.
And I wouldn't know what a Positive Crankcase Ventilation system was ...
Berni
Basil the 1955 series II
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Re: Oil dripping from air filter housing
Thanks for the reply to the question regarding air filter element condition.
Fitted to most BMC/BL vehicles at one time or another.
The cost of a new replacement valve is horrendous at around £70 plus so if the diaphragm was split/damaged or other damage occurred a previous owner may have decided to ditch the valve.
https://www.moss-europe.co.uk/valve-ass ... soc=515715
The valve is an important means of reducing oil leaks from the rear main area and other places and I would recommend it is reinstalled.
They do come up for sale on 'e' bay now and again. You will need the bracket, manifold adapter and hose pipe if not already in place/acquired.
https://www.ebay.co.uk/itm/MG-midget-br ... Sw32xa7LOZ
Fitted to most BMC/BL vehicles at one time or another.
The cost of a new replacement valve is horrendous at around £70 plus so if the diaphragm was split/damaged or other damage occurred a previous owner may have decided to ditch the valve.
https://www.moss-europe.co.uk/valve-ass ... soc=515715
The valve is an important means of reducing oil leaks from the rear main area and other places and I would recommend it is reinstalled.
They do come up for sale on 'e' bay now and again. You will need the bracket, manifold adapter and hose pipe if not already in place/acquired.
https://www.ebay.co.uk/itm/MG-midget-br ... Sw32xa7LOZ
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- Minor Fan
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Re: Oil dripping from air filter housing
I thought the restrictor was part of the PCV system but as Berni’s 948cc engine wouldn’t have that system the restrictor must have been more widely used. Thanks Phil, I will reinstate the valve when I get my pickup back on the road.
Regards John
Regards John
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Re: Oil dripping from air filter housing
I had been following that post but I don't think I have a breather port on my carburettor to do what you did.pgp001 wrote: ↑Mon Jun 18, 2018 7:29 pm You might be interested in what I have just done with great success.
viewtopic.php?f=4&t=68271
Phil
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Re: Oil dripping from air filter housing
You can use a 1¼" SU carb from a mini which is what I now have fitted, but it is quite possible to drill your existing one and add the connection yourself.
My original carb was well worn in the the throttle spindle anyway, so it was well worth doing for that reason alone, but I get a great feeling of satisfaction now every time I look under the car and find no oil slick.
Phil
My original carb was well worn in the the throttle spindle anyway, so it was well worth doing for that reason alone, but I get a great feeling of satisfaction now every time I look under the car and find no oil slick.
Phil