Just now, Zed Head said:

2nd edit, actually a post...just curious.  I wonder if people could pop their caps and see if they have rubber on there.  To CO's last post's point.  Just one of those curiosities.

TBH I didn't know there was supposed to be a gasket there either.  The gasket seems to be NLA though...

I have one on my cap. It's a black washer and if you poke at it with a screwdriver tip you can see that it's not quite as hard as the plastic cap, but it's pretty hard. Maybe 1/16 inch thick? ID is a snug fit on the threads, and the OD is about the same size as the raised boss on the valve cover?

I don't know how compliant they were when new so I don't know if it was always that hard, but I suspect it was slightly more compliant years ago. Every Z I've messed with has had one. I think you might just be not realizing it's there. It's really easy to mistake it for "part of the cap".

I'll take a pic tomorrow if someone doesn't beat me to it.

4 minutes ago, Captain Obvious said:

I think you might just be not realizing it's there.

Nope.  I looked closely because I thought that there should be one.  Then I thought "what a fine piece of engineering and manufacturing".  The reality is that they didn't need one there, as shown by my leak-free cap.

I saw this image before and looked at my cap. Mine looks like one piece. I thought about poking it with a screwdriver. I need to take another looks at it. I see a little oil around the cap, and was thinking about getting a more pliable seal.

The seal on my 240Z is more obvious.

I got one, thought it was part of the cap, pretty hard, but it def is a separate piece. the drawing make it look wider than it is.

 

Edited June 17, 20204 yr by Dave WM

Right. It's easy to mistake it for part of the cap. Here's some pics.

Cap, as it's normally seen:

Close up of the seal in-situ. Looks like all one piece:

But in fact, it's not. Used a thin blade to get a little separation and get things started, and the seal comes off. Note the step on the seal and the recess on the cap. Speculation on my part, but I bet the earlier seals (with the different part number) didn't have that feature:

And here's a close-up of the cap with the seal removed. You can see the recessed area for the step.

Could be I missed it.  I sold the car so can't check.  How does it seal without the rubber piece?  Did you try it?

Mine looks like the last pic, with the seal remove.

The seal on mine is in the valve cover. Car is 12/70 date.

 

46 minutes ago, w3wilkes said:

The seal on mine is in the valve cover. Car is 12/70 date.

 Ditto, 10/70 build date.

now I have to check the valve cover.

9 hours ago, Bigz Zee said:

Mine looks like the last pic, with the seal remove.

Yeah, then yours probably petrified and fell off some time in the past.

And for the guys with the O-ring style built into the valve cover, I guess that's the older style. according to the documentation, they changed over to the newer style in 71.