Question about oil filler cap

[2cams70]

I just noticed that my Lotus Twin Cam oil filler cap makes quite a rattling sound from inside when I shake it.
Is this normal or is something amiss? Doesn't look like it's easily disassembled.
Perhaps it has some kind of internal check valve for venting that may have come loose? I notice it has a small vent hole on it's upper surface.

[john.p.clegg]

Probably the end of the captive wire broken off in the cap...

John

[2cams70]

Thanks - that sounds very plausible

[elanner]

Yes, it's almost certainly the broken off nipple from the end of the wire strap that used to be there. If you give the cap a sharp tap on its side the nipple will probably wedge itself and stop rattling until it comes lose again.

Surprisingly, despite how they look, the caps are really quite easy to pry apart. I've done it a couple of times. You can carefully bend up two of the three flanges on the top half, thereby releasing the inner/bottom half. Go to a local bicycle shop and ask for an old broken brake or gearchange cable (they will doubtless have some). The wire, with a nipple at the end, will make a perfect replacement strap.

When you bend the two flanges back in place the chrome won't flake off and you won't even be able to see that you've done it. Crimp an eyelet to the other end of the strap and fit it under one of the cam cover stud nuts. Then the engine will look right!

Nick

[2cams70]

Thanks - helpful information