Just happened to be having a close look at my standard PCV valve and noticed that the pin on the base of the plate is not quite long enough to push open the small "trapdoor" valve at the bottom of the valve body.

Is it supposed to?

Is this normal or or do I have the wrong plate for this valve?

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68 Morris Cooper S Mk1 (*ex 78 1275 LS 4th last built, 70 Morris 1500 OHC & 70 MiniMatic)

Something is worn.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

So the pin should be long enough to push open the valve door in the base? Is that how it should work? Because my pin seems to be 0.8mm short of opening the valve. The end of the pin does not appear worn, you can still see the machining. What could be worn?

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68 Morris Cooper S Mk1 (*ex 78 1275 LS 4th last built, 70 Morris 1500 OHC & 70 MiniMatic)

Perhaps the valve is stuck down, ie is partly open.

I have a spare valve here which I'm not using, as I have converted to a Toyota one. Will look at it tomorrow.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Thanks, it looks closed, it's certainly doesn't look 0.8mm open.

There was a few different designs of valve, wondering if the innards varied and there's been a mixup years back.

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68 Morris Cooper S Mk1 (*ex 78 1275 LS 4th last built, 70 Morris 1500 OHC & 70 MiniMatic)

Phill,
On mine, the plunger doesn't reach the valve plate either.
Looking at it, it seems to me that the manifold vacuum pulls the valve plate back, and the plunger rises and falls in the guide with varying vacuum, this changes the flow restriction through the valve.
Mine is here if you need it, but looks to be the same as yours.

More recent design PCV valves are used on modern cars, they are cheaper too.. but if your'e after originality I guess you are stuck with the Smiths one.

[edit] I just found this on the web...
http://www.mgaguru.com/mgtech/engine/cv103.htm

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Thanks Kev. I'm happy with the smiths valve, I just couldn't understand the purpose of the moving plunger and I was trying to figure out how it all works.

That article is a good find. Very detailed explanation. Cheers

That

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68 Morris Cooper S Mk1 (*ex 78 1275 LS 4th last built, 70 Morris 1500 OHC & 70 MiniMatic)