Earl Cap

[wwt338j]

I think the TR250/TR5 and early TR6 ones were chrome plated to match the rocker cover which was also chrome plated. The later ones were bright zinc plated to match the rocker cover which was painted silver.
Sometimes second hand caps come up which have been chrome plated. Be wary of these because to clean and plate them involves removing the rubber seal which cannot be replaced.
David

[mrjim]

No votes for painted, then.

no, painted were just attempts at cleaning up the cad plated ones.

[Petes TR6]

Someone did have a NOS bright chrome cap on ePay recently, in the box and claimed it was for TR6 but who knows. I can't recall if it was Lucas or Stanpart, but definitely not from some aftermarket supplier. I doubt Triumph would have put a chrome cap on a factory painted valve cover.

[Willo]

Well I would have thought chrome cap with a chrome rocker cover, and cad plated for a painted cover.

[ima68tr]

No votes for painted, then.

[mrjim]

Cad plated was original but you could get a chrome cap also, so either would be correct.

[Mike K]

Boy trying to scare up a quart of Duckhams is pretty tough these days....

[frostr6]

FWIW, the cap on my '69 is definitely chrome, but i can only guess if it's original or not.

[tr250]

Chrome looks cooler regardless (imho)

[ima68tr]

Some were certainly done in chrome as mine have a brass rivet in the center. Only one of my chrome ones has the AC or OC4 on the ears though its rivet is chrome too.

I'm thinking zinc for the '250 and early 6 but jury's out on the later ones with painted v/c.

Can't beat the look of chrome, and TRs will be worth a lot more than they are now by the time you'll lose points at a concourse for a chrome one.

Tom

[RatRidgeRoadster]

Hard to say with certainty what yours is, but it looks like it might be chrome. I'm sure there have been some caps replated in chrome, but I think the problem in doing so is degreasing the cap sufficiently to not mess up the plating bath.

I think some other Marques had the same cap done in chrome. In fact, I bought a chrome cap just as the original cap but missing the "OC-4" marking.

My original cap is zinc plated. It will mostly clean up, but it has a couple of stains that just won't come out. If I could find the rivet holding the rubber washer, I would properly degrease it and replate it in bright zinc.

[damsonTR6]

Thanks Jim. So that is bright zinc and not chrome? Thanks

[RatRidgeRoadster]

Pretty sure they were plated in bright zinc.

[damsonTR6]

Which is correct? Was there changes during production. Chrome or painted? What you say?