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TR2/3/3A TR 3A Gas Caps

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Tinkerman

Tinkerman

Darth Vader
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I'm sitting here looking at three gas caps, excuse me petrol caps. One came off my car two others I bought on ebay. Come to find out the two I bought on ebay are TR4 or later caps. So that leaves me with one grody looking cap for my car. My plating guy tells me it is pot metal and he doesn't do pot metal. A plater that does, tells me I'm looking a BIG $$$$$ to plate it.
Being the basic miser that I am I am looking at alternatives, buying a new one from one the big 3. Seems to really be the only alternative that I have. Anyone have any experience with buying one? How did it look etc. etc. and where did it come from?
Appreciate any and all thoughts.

Tinkerman
 
On the TR3A, there were two different designs. Mine is an early TR3A and there is a large threaded nut below that secures the petrol cap to the rear deck. This design makes it very hard to put the short length of rubber hose into place between the extension of the cap and the inlet on the top of the tank. To help get this hose in, I cut it a little shorter and forced it on. I left it long enough to still secure the hose with the two large hose clamps.

On the later TR3A I restored, the assembly was much easier because they had changed the design.

Maybe the ones you say are from a TR4 may have been from a late TR3A. From the outside, no judge at a TRA concours can tell which one you really have.

When I restored mine from 1987 to 1990, I bought a new gas cap. It's still on after 98,000 miles ans still looks like new. If you put a new one on, it'll still be looking new in 20 years. You decide which you prefer.
 
The repro one I bought 10 years ago looks 20. No pitting, but the chrome is thin and cloudy...foreign, I'm sure.
I will be looking to do something with it during my restoration.
 
I have the early cap (pre TS60000?) and got the repro form Moss. Still looks excellent 5+ years later.

All I replaced was the topmost section so it was just a matter of unscrewing the old cap and threading in the new.

Made a grommet (gasket paper) so the cap would tighten up with the release ear pointed the right way (driver's side).
 
Thanks Geo, that gives me something to hang my hat on. I figure that if mine looks good five years from now I'm ahead of the game. Plater was talking $200 to do mine I can buy one for $75.

Thanks for the responses folks!

Tinkerman
 
Don, mine has the threaded nut on it. The others I have do not have the threaded nut and thats why I feel that they may be TR4 caps, that and the discription in the Moss catalog.
Thanks for your thoughts.

Tinkerman
 
Hi all,

The improved (to fit) later filler cap on the 3A was standard right thru 4,4A,5 and early 6. As mentioned, it has a plain metal connector pipe that pushes down thru a waterproofing body grommet into the rubber connector hose to the tank. This type filler cap is secured by the upper hoseclamp around the connector hose, and the tongue latch is supposed to point towards the driver's side.

As the rubber connector hose fits over the tank inlet socket, you need to get the bottom hoseclamp really tight or fuel can get past the connector hose when you fill up, or when a full tank sloshes. Then you get really strong odours in the cabin, and dangerous fumes in the boot (trunk).

It's easiest to upgrade to the later cap on a 3A, as you have to be a contortionist to connect up the earlier threaded one.

Later 6's had a filler cap with a different latch that wouldn't spring open in an accident.

Regards,

Viv
 
Sorry, I disagree. TR3A from TS60000 still had a nut & washer that locked the filler assembly to the rear panel; which continued through mid-TR4 (CT19770). The part number changed with the introduction of the TR4, but I'm not certain what the difference was (suspect it was a longer extension under the panel), anyway the caps look identical.

After CT19770, the fillers used a grommet instead of a nut & washer; but there were several different assemblies used (for example TR250/5 had a magnetic catch instead of a mechanical).

Personally, I don't find the early cap difficult to install at all, once you figure out that the supplied connector hose is way too long. Install the cap first, then trim the hose to length and slide it fully onto the neck of the tank while you install the tank. Then slide it up onto the neck of the tank & secure with hose clamps. A little lube makes things easier.
 
Randall,

Interesting info. When I had the full set of wide mouths, the very late 3A and the 3B both had the later fillers. I was rebuilding both the early and late 3A's together and the early 3A was ahead, so I snitched the later filler cap for the early 3A that I still have, and brought a new cap for the later car when its rebuild caught up.

Don Elliott has rebuilt both the early and late cars and also describes his later car as having the new type filler cap.

I had thought that the changeover might have been at TS60000 with the new tank, but nothing is recorded, and you obviously have info that suggests not. I am aware there were subtle differences up to the early TR6, but visually it looked the same.

Possibly old design caps were replaced over the years, as the chromed top was prone to pitting.

It's always interesting to discover something new.

Best regards,

Viv
 
The 2nd TR3A that I restored (TS 81551 L) had the later gas cap when I took it all apart. I ordered a replacement because the one that had been on the car was badly pitted. The new one was the later design and was not the threaded nut design.
 
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