CJD
Yoda
Offline
Well, it's been a while since I posted a "how to" thread. This is one I've been meaning to get around to for quite some time...that leaky POS fuel valve the TR2 and early 3's came with. For those who have seen one, they use a plug of real cork to seal the fuel. I spent hours making a perfect cork when I rebuilt the valve, thinking that, like most things, if I did it right it would work and not leak. Well, it worked great...for about a year. I then had to adjust it to "bulge" the cork, as it was meant to be adjusted. That worked for another year, where it would leak if in the "on" position, so I had to open the bonnet and shut off the fuel when the car would sit for a while. Another year down the road the valve began leaking all the time, in all the positions, and no adjusting would help
The long term study...cork is never going to seal for long periods. It, like all wood, will swell and shrink. If it swells, it binds. If it shrinks, it leaks. Both are inevitable.
So here is the fix...
I obtained a lathe as a late life hobby. I thought about re-turning the entire valve piston, but decided, instead, to simply create a brass slug to take the place of the cork. It now uses O-rings to seal, which should last at least a decade longer than the cork did. The beauty is that a later FO could switch back to the cork, since no mods to the valve other than replacing the cork with the brass slug was done. Don't know why anyone would want to go back to cork...but the option is there.
Here is the cork plug shown with the new brass slug. Note it will take 3 O-rings to seal the gas from 2 sources plus the valve handle.
Starting assembly, the adjuster goes through a small o-ring and then through the slug. This o-ring is needed to prevent gas from flowing up the adjuster rod to the handle center.
2 larger 0-rings go on the outside of the slug. The upper seals to atmosphere. The lower splits the intake fuel from the outlet on the valve.
Here is the new complete piston assembly. Cork must have been REALLY cheap for Triumph not to use O-rings originally...or maybe they were too new?!? Note the L-shaped cutout. A screw from the main cylinder body enters the slot, both retaining the piston in the cylinder and allowing the piston to be turned to a "locked" position when open.
Final assembly. The fuel comes in the bottom inlet, and passes out through the right inlet. So, when the piston assembly is down, it blocks the flow of fuel. When up...it allows fuel to pass.
This is the shut-off mode...where you can see the slug blocking the outlet passage. The O-rings must be placed above and below the port.
And the open mode, where the cylinder is raised to open the outlet port.
These valves were so bad originally that it is allowed to remove them from the car and still get 100 points. It's considered a "safety" item in judging. I would have just removed this one, but hey...it is nice having the ability to cut off the fuel to empty the filter bowl without getting doused with gas!
Now I can sleep peacefully, unconcerned that the air compressor kicking on could explode the house.
Chow!
The long term study...cork is never going to seal for long periods. It, like all wood, will swell and shrink. If it swells, it binds. If it shrinks, it leaks. Both are inevitable.
So here is the fix...
I obtained a lathe as a late life hobby. I thought about re-turning the entire valve piston, but decided, instead, to simply create a brass slug to take the place of the cork. It now uses O-rings to seal, which should last at least a decade longer than the cork did. The beauty is that a later FO could switch back to the cork, since no mods to the valve other than replacing the cork with the brass slug was done. Don't know why anyone would want to go back to cork...but the option is there.
Here is the cork plug shown with the new brass slug. Note it will take 3 O-rings to seal the gas from 2 sources plus the valve handle.
Starting assembly, the adjuster goes through a small o-ring and then through the slug. This o-ring is needed to prevent gas from flowing up the adjuster rod to the handle center.
2 larger 0-rings go on the outside of the slug. The upper seals to atmosphere. The lower splits the intake fuel from the outlet on the valve.
Here is the new complete piston assembly. Cork must have been REALLY cheap for Triumph not to use O-rings originally...or maybe they were too new?!? Note the L-shaped cutout. A screw from the main cylinder body enters the slot, both retaining the piston in the cylinder and allowing the piston to be turned to a "locked" position when open.
Final assembly. The fuel comes in the bottom inlet, and passes out through the right inlet. So, when the piston assembly is down, it blocks the flow of fuel. When up...it allows fuel to pass.
This is the shut-off mode...where you can see the slug blocking the outlet passage. The O-rings must be placed above and below the port.
And the open mode, where the cylinder is raised to open the outlet port.
These valves were so bad originally that it is allowed to remove them from the car and still get 100 points. It's considered a "safety" item in judging. I would have just removed this one, but hey...it is nice having the ability to cut off the fuel to empty the filter bowl without getting doused with gas!
Now I can sleep peacefully, unconcerned that the air compressor kicking on could explode the house.
Chow!