Radiator cap identification needed.

[Alex D.]

Purchased this cap for the ornament but don’t know the true application. The cap is nickel plated brass with an inside diameter of 2 inches and a 16-thread pitch. The hole in the center is 3/8 inch. Possibly late teens or early 20’s, but for what?

Would appreciate any feedback. Thanks

 

 

[Mark Wetherbee]

I believe it is either Rolls or Bentley.

[motoringicons]

Definitely looks Rolls Royce. There were about a million different sizes of that Rolls cap used from the beginning until they stopped using that style of cap. Hard to know what year without the dimensions. 

[Alex D.]

Thanks for the quick replies. I had no idea.

 

Outside diameter- 2 3/8 inch / 60mm

Inside diameter-   1 15/16 inch / 50mm

Height-   21/32 inch / 21.5mm

Thread pitch per inch - 16