I thought I would share a refurbishment I am doing on a tappet chest oil separator chimney from a spare engine.
This type of breather was used on the later Morris Minor 1098cc A-series engines and in the case of my car, the chimney is connected to a PCV valve on the inlet manifold.
A-series engines have a reputation for leaking oil. When I was a student this was a big problem because engine oil is expensive quite apart from the mess and environmental damage from oil leaking all the time.
Some years back, I refurbished the tappet chest chimney on the engine in my car. It was completely blocked with rust. After refurbishment, the engine does not leak oil at all. This is because the breather system is working as intended and relieving crank case pressure.
The chimney and pipe from the tappet chest cover are brazed in position. The chimney itself was originally filled with a mesh of wire wool. Unfortunately, this was not stainless steel and since blow-by gasses contain water the mesh rusts into a solid lump. The mesh both assists in separating out oil and acts as a flame trap. If the PCV valve was faulty and the engine backfired then potentially a flame could ignite the blow by gasses and even cause the crankcase to go bang.
Ideally, the chimney would be removed by heating and releasing the brazing. Then cleaned out, mesh replaced and brazed back together. I do not have the skills or equipment to do this so I poked down the chimney and got clumps of rusted mesh out and eventually after partially filling with water and shaking and more poking got all of the rubbish out. There are some clips that originally held the mesh in. With very long needle nose pliers these can be pulled out.
After cleaning out the can, the flame arrestor must be replaced and I used stainless steel pot scourer. It is tricky to feed this in but it can be done with patience. To ensure the mesh cannot fall into the engine (very unlikely), one of the clips can be re-fitted.
I hope this is of some use
Edit: I do actually have a torch that can get hot enough to braze with the right gas (MAPP) but no brazing rods at the moment. I may have a go because I am intrigued as to whether there is anything else inside and I would like to return the piece to better than original condition with stainless steel mesh and clips. I have never tried brazing but I do have experience with plumbing soldering.
Stephen
The chimney type tappet chest cover clearly showing how it is brazed together
Lumps of rusted mesh/wire wool
More rubbish from inside
The clips that held the mesh in the canister
Oil Separator flame trap "Chimney"
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- svenedin
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Oil Separator flame trap "Chimney"
1969 1098cc Convertible “Xavier” which I have owned since 1989.
Stephen
Stephen
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- svenedin
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Re: Oil Separator flame trap "Chimney"
You mean except for the wire gauze/wool and the clips? This must have been put in before the lid was fitted.
Stephen
1969 1098cc Convertible “Xavier” which I have owned since 1989.
Stephen
Stephen
Re: Oil Separator flame trap "Chimney"
You may remember Stephen, a member (pgp001) modified a canister by making the top removable to assist maintenance, he hasn’t posted here for a while.
- geoberni
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- svenedin
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Re: Oil Separator flame trap "Chimney"
I did not remember that! Thank you for reminding me Les. I will search for that post. That sounds like a good idea but in theory at least with stainless steel wool in the canister it should always be possible to remove sludge with something like carburettor cleaner. It is only when everything is corroded inside the canister that drastic action has to be taken. I would suggest this is actually the case for most cars unless this job has been done.
Stephen
1969 1098cc Convertible “Xavier” which I have owned since 1989.
Stephen
Stephen
- svenedin
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Re: Oil Separator flame trap "Chimney"
Thank you. That is a great idea but beyond what I can do. It was daft of BMC to put material that can rust so badly inside the canister.
I noticed that nobody mentioned in that thread that the gauze is not just to separate out oil mist but it is also a flame arrestor (like the gauze on a Davy lamp). If the engine should backfire and the breather pipe is connected to a faulty PCV valve on the inlet manifold then the oil mist could ignite. Leaving out the gauze is a bad idea.
It was great to see the inside of the canister in the other thread. My curiosity is satisfied and I don't need to take mine apart now.
Stephen
1969 1098cc Convertible “Xavier” which I have owned since 1989.
Stephen
Stephen
Re: Oil Separator flame trap "Chimney"
Hi,
having removed the metal mesh out of the crank case venting canister one may think about installing a seperate flame trap (https://www.ebay.de/itm/264475139257) that is used in Range Rover V8. It then can easily be removed and cleaned separately if necessary.
I did so in my Traveller after installing a vacuum pump to produce negative pressure to the crank case and it works perfectly.
Chris
having removed the metal mesh out of the crank case venting canister one may think about installing a seperate flame trap (https://www.ebay.de/itm/264475139257) that is used in Range Rover V8. It then can easily be removed and cleaned separately if necessary.
I did so in my Traveller after installing a vacuum pump to produce negative pressure to the crank case and it works perfectly.
Chris
Fuirich bhur bruadar
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Re: Oil Separator flame trap "Chimney"
I did the same as you in the 90s when I worked in an engineering factory. I remember using stainless steel wire wool. It is still working as it should.
1969 Traveller in Almond green. Owned since 1979.