GT6 Mk1 GT6 glass domed fuel pump

[byakk0]

Anyone ever rebuild one of these? The part in question is the little check valves. I've got a rebuild kit. The diaphragm and gaskets are easy enough, not so sure about the check valves.

I think the new valves are the ones in the two round rubber seals but they look entirely different.

It's hard to tell, but they look like the valves in this land rover kit

It's the one on the right in question. The one on the left is for the early KC engine (though the only difference between the two is the lever)

Oh, and if anyone knows of a source for glass domes, let me know. (even if it is from some entirely different application and it still works)

 

[dklawson]

I have rebuilt exactly "1" of these pumps. It is in my collection of parts yet to be used. What's your question about the pumps and valves?

 

[byakk0]

I have rebuilt exactly "1" of these pumps. It is in my collection of parts yet to be used. What's your question about the pumps and valves?

Info from another person on another site tells me my issue is the valves...
Backstory:
first of all, my car has been off the road since mid 97. Since then I have dismantled the car for a complete resto, not including the engine (yet), which ran up to the day I parked the GT6. I have had the engine and transmission, as a unit (not yet separated) sitting on a test cart, which I started from time to time.
At one point I had trouble with the fuel pump, so I swapped it for the one on my spare block.
When I ran my engine I would have to use the prime lever and starting fluid to get it started, would run it for a little while, then put it to bed till next time.

I now have my chassis rebuilt, tub on the chassis, and engine bolted in place. The car is not yet complete, but I would like to be able to move it around under it's own power. I didn't think much of why the engine only ran for a short time before dying.

Now to the meat of the question: Last week when I was hooking everything up I discovered a leak on the outlet side of the fuel pump. Turns out I had cross-threaded the brass fitting and messed up the threads, so it leaked. This is where the fun started, and why I have 2 different pumps in that photo.
I pulled the pump off so I could swap tops. Sure, I could have done it on the block, but for some reason I removed it from the block. In the end that part proved to be a good thing.
I installed the pump back on the block and primed it, gas flowed but not when cranking, and I realized the lever was not coming in contact with the cam lobe-that would explain why my previous times of running the engine only lasted about 30 seconds or so-long enough for the carbs to run dry.

after struggling mightily trying to get the lever on top of the cam as stated in the manual, I pulled my other pump and compared the two, and discovered the different arms. (turns out my installed and working engine is a KD GT6 engine, and the spare block is an early KC engine). Another swap of tops so I have a good top on the correct base with the curved arm and I got a good fit of the pump. A crank of the engine showed the diaphragm moving up and down now.

At this point I reassembled the pump, ran the prime lever, and got nothing. Over the course of the afternoon I took it apart multiple times and tried multiple things, including breaking out my rebuild kit.
At one point since then I got a little fuel pumping manually into the bowl, but I could see air sucking in around the new glass-to-body rubber seal. After making a new gasket out of cork (as it was originally when I bought the car in 95), I have yet to get it to prime manually or with engine cranking, even with trying the body with the stripped outlet. It's leaking air somewhere.
Now no combination of my two fuel pump parts, gaskets, and old or new diaphragms work anymore, when just the day before they were working fine. (aside from the lever bit)

So the question now is
1) Am I missing something simple?
or 2)are my check valves indeed shot and leaking air? if so, anyone have any experience replacing them?
(my question about the glass stems from my son being curious and accidentally breaking my spare. I'd like another)

Sorry for going on and on...but there you go.

 

[TomMull]

The inlet valve and outlet valves need to be installed correctly, so they work in opposite directions. They need to fit the bodies and be sealed with the gaskets. I would double check to make sure that is the case. If either valve does not work, the pump will not pump. If the diaphragm is intact and the pump does not work, there isn't much other than the valves that could be at fault, with the exception of blockage somewhere.
Note that you can bench test the pump by putting a finget on the inlet and outlet and pumping the lever. You should feel a bit of air pressure on the outlet and suction on the inlet. The suction sound will be quite audible also.
Tom

 

[dklawson]

As above, if the valves are installed correctly and not hindered by debris, the pump should work when you operate either the priming lever or the pump foot. You mentioned making a new cork gasket. Take a careful look at that gasket again and make sure it is sealing. If there are any gaps or voids on that gasket the pump will draw air in around the glass and the pump will not work.

 

[byakk0]

sounds good. maybe something has decided to block the valves in all the toying with them I have done. I'll see if I can clean them out first before I try to remove them, especially seeing they were functioning when I started this whole thing a week or so ago.
The gasket is a little over-sized internally, so it shouldn't be the issue, but who knows. The last gasket I made a few years ago gave me no trouble at all.

 

[byakk0]

update:
I didn't do anything with the valves, but as luck would have it my spare pump body the valves just don't seem to work but I wanted to use this one as I accidentally cross-threaded the outlet sometime in the past on my other pump. Ironically, the valves on the cross-threaded pump do work, so I ended up using 2 brass fittings to convert from a compression fitting to a 1/8" barbed hose fitting. Problem solved.
Engine fires right up and stays running now (as well it should!)