Tappet chest cover - confusion

[chiseldonbob]

I'm in the process of replacing the gasket on the tappet chest cover on my 1969 traveller. The engine is a recon which I fitted back in the late 90's.When ordering the new gasket I noticed that the cover, which has a concave surface, (see pic) was not the same as illustrated in the Haynes manual/ESM graphic. I also noticed that the pipe with a filter is connected directly to the top of the manifold see pic 2, with a flat disc containing a filter.

So this looks like the pressure from the tappet chest is relieved by allowing the air to pass out through the pipe, gets filtered before being expelled through the manifold. I'd appreciate it if someone can confirm if this is correct and if this is an old design which was superceded by the simple crankcase vent pipe shown on the Haynes graphic?

Thanks in advance

[svenedin]

You have something of a rarity there! I see from your post that this is a replacement engine. Can you confirm the first part of the engine serial number please. Is it 10ME?

That type of manifold is designed for a Smiths PCV valve. You have the spigot and the bracket for the valve.

The later tappet chest covers are concave, earlier ones (948cc) are convex. The concave type uses a neoprene gasket and a cup washer and seal under the head of the bolt that secures the cover.

My car has exactly this system and it would look like this.......

See this very recent thread which list the relevant gasket and seal part numbers: viewtopic.php?p=697951&hilit=tappet+chest#p697951

Be aware that the chimney oil separator attached the tappet chest cover is often blocked. It contains a type of wire wool that corrodes and gets totally blocked making the engine breathing system inoperative. See if you can blow easily through the hole in the top of the chimney. If not or if there is resistance, you need to clean it out. This involves pulling out the corroded wire wool with long forceps or pushing it out with a screwdriver and then refilling the chimney canister with stainless steel pot scourer. It must be stainless steel and definitely not a Brillo pad with soap! viewtopic.php?p=697912&hilit=oil+separator#p697912

Stephen

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[philthehill]

You have the later cam follower (tappet) access covers which use a neoprene/rubber gasket.
The canister is a oil separator and has a gauze element inside to separate the oil from the crankcase fumes.
The disc on top of the manifold is a Pollution Control Valve (PCV) which allows the fumes from the engine to be drawn into the manifold and consumed in the combustion chamber.

[svenedin]

You have the later cam follower (tappet) access covers which use a neoprene/rubber gasket.
The canister is a oil separator and has a gauze element inside to separate the oil from the crankcase fumes.
The disc on top of the manifold is a Pollution Control Valve (PCV) which allows the fumes from the engine to be drawn into the manifold and consumed in the combustion chamber.

I would argue Phil that PCV stands for "positive crankcase ventilation".......

https://en.wikipedia.org/wiki/Crankcase ... ion_system

https://mgaguru.com/mgtech/engine/cv103 ... 20valve%22.

[philthehill]

You can call the valve what you like but the valve was fitted for the control of pollution caused by piston blow past escaping from the crankcase.
It has been called a pollution control valve for many years without dissent.
The valve is designed to creates a negative pressure in the crankcase.

[svenedin]

You can call the valve what you like but the valve was fitted for the control of pollution caused by piston blow past escaping from the crankcase.
It has been called a pollution control valve for many years without dissent.
The valve is designed to creates a negative pressure in the crankcase.

Yes Phil, you know I am well aware what it is for! Never mind.

Stephen

[geoberni]

According to the Parts List, it wasn't a PCV, it was a VBC.... Valve - breather control ...

For some reason, the pdf I have of the AKD 3541 doesn't have the illustration to go with the list, I guess that page had been lost, but the parts are listed.....

Closed Circuit Breathing.JPG (85.49 KiB) Viewed 154 times

[myoldjalopy]

So as Phil suggests, we can call it what we want then!

[chiseldonbob]

Thanks all for the valuable information. The engine doesn't have a number on it, the plate was ground off when I bought it. Thanks for the info on the set up and the advice on cleaning out the oil separator. I'm happy to use the 3 letter acronym, at least I now know it has a useful purpose.

If I've understood things correctly I can assume that the engine is of a later type, is there any way of identifying exactly when the PCV/VBC was introduced into the engine design??
This info is really helpful so thanks everyone. Bob.