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TR2/3/3A TR3A Gas cap help

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GilsTR

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I have a TR3A post 60,000. I could use some of the valuable help from forum members re what I think might have been a "O" ring ...or? When the cap is opened and you are looking down from the top you will see where the ridge from the cap seats into the extension. If you will the ridge is on the opened part of the cap. Where this seats I think there should be a gasket or "O" ring when the lid is closed . Nothing is offered by the big 3...and no part is shown. I see something in that place on other cars...yet mine has nothing. What goes there? Help appreciated! Gil
 
Hey Gil
There should be a rubber gasket on the gas cap where it seats to the filler neck.
Dan
 
Dan...In looking at Moss...they show no gasket...and sales people only know what is in the book. Any clue where I can get a gasket like that? Gil
 
Gil: you can make your own gasket. Go to your local auto store and bet some gasket material. measure the OD of the filler neck and cut one or more rings to fit.
 
Frank is on the right track. He may have missed the detail of where you need a gasket, but the notion that you need to make your own is right. A little gasket material, measuring, cutting and glue: presto! a new gasket. It's not a very critical location. Are you leaking fuel?
 
Might be easier to lay a length of O-ring cord into the groove; or maybe even just fill the groove with RTV and wait for it to set up. As Moses says, these caps don't seal tightly (there's even a vent hole built into it), so the 'gasket' is more of a cushion for where the steel plug hits the pot metal body than a seal.

It was considered part of the filler assembly; I've never seen it even pictured separately, let alone for sale separately.
 
I like the RTV suggestion. I am in the process of trying to illiminate the smell of petrol from my garage (in a vain attempt to appease SHMBO) and this will now be part of my plan of attack. Am I embarking on a futile excersize or do some of you TR3 owners have cars that don't reek of petrol in the garage?
 
Used an unused square-profile O-ring that had come with the original-style cannister oil filter (they used to put several in there). Cut it to length and pressed in down in there. The original material may have been moulded into the space -- hence not offered as a part.
 
Adrio said:
...Am I embarking on a futile excersize or do some of you TR3 owners have cars that don't reek of petrol in the garage?
Click to expand...

Should be possible. Perhaps you have already checked them but my first 2 stops on this journey would be the fuel pump connections and the bottom of the jets.
 
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Should be possible. Perhaps you have already checked them but my first 2 stops on this journey would be the fuel pump connections and the bottom of the jets.[/QUOTE]

And 3 the fuel shut-off valve.
 
Geo is, of course, correct that these are places to check for fuel leaks.

The tank can be a source of smells too. Here's what worked for me to largely eliminate fuel odors originating at the tank. I plugged the vent, next to the fuel gauge sender and installed a vented locking gas cap. Soon as I got that done, Becky quit complaining. It must work. Even I noticed the difference!
 
My first stop was the jets. they do leak but I remember the smell from before that. I wonder how much comes out the bowl vents. As to the tank vent I was wondering about hiding a carbon canister between the rear seat and the trunk and running the vent into that??

I like the square O-ring from the spin on adapter---did I keep all those extra ones from my two adapter kits---since I have a use for them now it must mean I did not keep them, I only keep things I never fins a use for :smile:
 
Adrio said:
Am I embarking on a futile excersize or do some of you TR3 owners have cars that don't reek of petrol in the garage?
Click to expand...
The project '3 spent two weeks locked in the garage (along with one of the Stags). I didn't notice any fuel smell (which doesn't mean much), but more importantly SWMBO did not complain of it either. But then, I've improved my garage ventilation as well, so that may be part of it.

I would also check the float bowl mounts for leaks (probably most common on my cars, after switching to O-rings for the jets); and the bottom of the fuel tank (rust pinholes).

Adding a carbon canister isn't a bad idea at all; but keep in mind you need a fuel separator of some sort (I have found that liquid fuel runs out of the tank overflow during hard turns) plus a purge vacuum line to pull fresh air through when the engine is running. Otherwise, the carbon will quickly get saturated (it only holds a tiny amount anyway) and be totally ineffective.

Don't know offhand if the TR6 used it, but later Stags use a vapor separator that would probably fit in the space above the tank on a TR3. Hopefully high enough to keep liquid fuel out during hard turns; but adding a dip tube (so the tank cannot be filled all the way) would probably still be a good idea.

Come to think of it, perhaps some don't know this : With the stock arrangement, you need to be sure NOT to fill the tank all the way to the top and then park it in the garage. Gasoline expands with heat far more than steel does, and generally comes out of the pump pretty cool. So it can quite easily expand enough in a hot garage to spill out the overflow.
 
Gil, I used an O-ring to make that seal, of course there is no gas in the tank yet and I may find, when I do put it in, that I have a problem. I took the cap to my local auto parts store and got it fitted with an O-ring.

Good luck, Tinkerman
 
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