Quiz...can you identify this?

[David Morris]

Hi All,

Just a bit of light relief! Can you identify this item?

Clue...it is fitted to every Javelin and Jupiter engine. Some while ago, there was a lot of debate about this item, which you can see from the photos, has had a hard life.

All the best,

David

[PJGD]

Item Number 80.

GM PCV Valve Patent.png

[David Morris]

Hi Philip,

Well done! From your illustration, in Fig.2, I think it is item 76. I have heard it referred to as part of the air flow pintle valve.

It sits inside the valve assembly, made by AC, and mounts on the oil filler tube. There used to be lots of discussion about this valve, which you can dismantle to expose this component.

I have found several where the spring is broken or the valve seat pitted and worn. As you can see, this one is not in pristine condition and personally, I would be lapping the valve seat.

When was the last time you examined yours?

Good detective work!

All the best,

David

[Keith Clements]

What symptoms are exhibited before any work is required on the valve?

[David Morris]

Hi Keith,

There was a time, several years ago, when this valve got the blame for almost anything. People were chopping coils off the internal spring, drilling out the vent holes or even putting washers under the spring, to increase the tension. In the 1970’s, they were the ‘go-to’ item for any rough running. Anything wrong with the engine, and you started by changing the air valve, probably as it is one of the easiest things to change!

I haven’t seen new ones for sale for a long time, so I guess the ones on the engines now are probably either original or close to that age? For some time, I didn’t realise that they can be dismantled. You need a good vise and a large socket, but they unscrew into the two parts, revealing the spring and the pintle valve inside. Have a good examination of the face of the pintle and the seat. They can be lapped to get a good seal. Mostly, the seats will be worn and ‘hammered’. I guess the valve must oscillate a lot during running?

In answer to your question Keith, and setting aside the extravagant claims that owners shoveled onto this component, I remember that the most likely effects of a defective valve are a ‘lumpy’ tick over and flat spots on acceleration. People just kept a spare one in the tool box and changed it when experiencing these problems, without bothering to strip the valve ( or not realising that you could strip them and recondition ) and cure the problems. It was just too easy to change!

Hope this helps,

All the best,

David

[Keith Clements]

David you are quite correct. I asked the question knowing all that you said but never having suffered from a faulty one. Leaks in the tube feeding it yes caused loads of smoke. I now have a diagnostic kit with vacuum gauge that should show any issues.