Breather systems

[les]

Below is my current set up, I have another manifold to suit a PCV valve installation, would changing to this give better breathing, or at least be worth doing ?

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[svenedin]

So your current set up is a pipe from oil separator to carburettor breather inlet? If so, that was the arrangement for the very last Minors as I understand. The earlier arrangement was a PCV valve which is what I have on a 1969 car. Basically I think the PCV was dropped as the breather carburettor is simpler and there is less to go wrong. Your arrangement gives a strong vacuum at idle or light load and a weak vacuum when the engine is under heavy load. That is because your breather is basically at inlet vacuum. The PCV valve is more sophisticated and is designed to provide a constant moderate vacuum. Which actually works better in the real world I do not know.

Stephen

[les]

Well I’ve got a slight oil leak and before I do anything drastic, I wanted the best breather system possible, to eliminate that.

[svenedin]

I was ever so pleased with myself that I didn’t have any oil leaks but I took the car to the Isle of Wight at the weekend and the car is definitely leaking oil. I used a pint of oil per hundred miles! Investigating where the leak is coming from is my next job. The weather was awful whilst I was away so I couldn’t get under the car. It’s the longest run (220 miles) my car has done in a very long time. I suspect it didn’t like sustained high speeds very much.

Stephen

[les]

Stephen, you might need to wipe the oil away and from then on keep an eye on where it appears again, after gentle motoring. As I suspect it has blown all over the place when on the move at higher speeds. Weather looks to be getting better, good luck.

[svenedin]

Stephen, you might need to wipe the oil away and from then on keep an eye on where it appears again, after gentle motoring. As I suspect it has blown all over the place when on the move at higher speeds. Weather looks to be getting better, good luck.

Thank you Les. Since I got back from my trip the car has been in the garage and it has a drip tray underneath. The oil leak is at the front of the engine and probably from the front U shaped sump seal. I am going to drop the sump, clean everything up and refit with new gaskets. I have some of the alternative neoprene rubber U-shaped seals instead of the cork. It looks trivial with the car standing or idling but it isn't a trivial oil leak when the car is being driven at 55-60 mph for several hours. The IoW trip was a test run for Minors on Tour to Holland in a few weeks time and it was entirely as planned to bring problems to light now rather than on tour.

Regarding your oil leak, have you checked that there is good unrestricted air flow through your oil separator? Also do you have the long type, breather oil filler cap? This is a service item as it can become blocked. It can either be replaced or given a wash in petrol. The gauze inside gets blocked.

Stephen

[les]

Yes the separator is clear, I’ll check the cap.

[philthehill]

As regards the neoprene sump end seals - they may need to be trimmed in length to suit.

[svenedin]

Thank you Phill. I have 2x TAM1171. I happen to have a (clean) spare sump on the dining table and I have done a trial fit. The TAM1171 fit perfectly and do not appear to need trimming. The cork seals on the other hand are way oversize and will need trimming. I had intended to have the spare sump painted and ready to do this job at my leisure but it is not done so I will be taking off and replacing the sump that is currently on the engine. Of course I will first check that all of the sump bolts are secure. It may just be a few loose bolts. Wishful thinking probably.....I have now agreed to fix a friend's lawnmower (carburettor issue) so it's going to be a few days of fun.....

Stephen

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[philthehill]

The problem with the neoprene seals is that they are near solid and cannot compress like the cork seal.
The neoprene seals only appear to be available for the 1275cc engine and that has a larger radius rear sump opening so requiring a longer seal (Pt No: TAM1089) and different sump. The front seal for the 1275cc engine (Pt No: TAM1171) is what you appear to be using for both front and rear seals as the 948cc/1098cc engines have the same radius openings at the front and rear of the sump.
I do have a set of neoprene sump seals available but my preference is to use the cork seals properly trimmed and seated.
The longer cork seal is suitable for 948cc, 1098cc and 1275cc engines when trimmed to the correct length.
Give the side gaskets a good coat of grease and attach them to the block before offering up the sump.
Whilst I do not normally advocate using a sealer on cork sump gaskets I consider that with the hard neoprene seals a smear of sealant goo would not go amiss.

[svenedin]

The problem with the neoprene seals is that they are near solid and cannot compress like the cork seal.
The neoprene seals only appear to be available for the 1275cc engine and that has a larger radius rear sump opening so requiring a longer seal (Pt No: TAM1089) and different sump. The front seal for the 1275cc engine (Pt No: TAM1171) is what you appear to be using for both front and rear seals as the 948cc/1098cc engines have the same radius openings at the front and rear of the sump.
I do have a set of neoprene sump seals available but my preference is to use the cork seals properly trimmed and seated.
The longer cork seal is suitable for 948cc, 1098cc and 1275cc engines when trimmed to the correct length.
Give the side gaskets a good coat of grease and attach them to the block before offering up the sump.
Whilst I do not normally advocate using a sealer on cork sump gaskets I consider that with the hard neoprene seals a smear of sealant goo would not go amiss.

Thank you Phil. I am not very happy with the cork seals that I have (ESM) because they seem a bit too narrow for the channel in the sump and they want to twist. Les noted this in a thread from a while back. I will take my time offering up and making whatever adjustments are needed. I am in no hurry and I have a helper today (at least to the extent of sometime to make tea). If the neoprene hard seals are a problem I can use the cork ones. Also if this does not work I still have time to do it again before Holland.

One thing though. The sump side gaskets when lined up with the bolt holes want to overlap the u-shaped seals. Should they be trimmed so that they abut but do not overlap the U-shaped seals or is the overlap correct? Please see photo.

Thanks once again for you help Phil and my apologies Les for hijacking your thread.

Stephen

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[philthehill]

The side seals must overlap the sump neoprene gaskets and they must abut hard against the main bearing caps.
That is why the side gaskets must be fitted first.
That neoprene seal looks to be too long.

[svenedin]

The side seals must overlap the sump neoprene gaskets and they must abut hard against the main bearing caps.
That is why the side gaskets must be fitted first.
That neoprene seal looks to be too long.

I think the neoprene seal is fine. It will compress to the correct length with pressure from my finger. We shall see......proof is in the pudding.

Stephen.

[svenedin]

All done. Very simple. Not a leak from the sump at all. Leak from oil filter. Absolutely dry around timing belt cover (previous job). Sorted. Thank you for sump advice which will be very useful in future.

Stephen

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