Centurion Fuel Filter

[Malcolm Towrie]

Robin,
I cleaned some more paint of the filter and found it was made by Tecalemit. It's very similar to a Vokes. But I assume it would have a much higher flow rating for the Meteor engine.
Malcolm

[jdmcm]

Hi Malcolm

did you ever solve your filter hunt? Perhaps with a locally sourced element? I am in the same boat as you, our Mk5 has the filter on the RH firewall just inside the engine compartment, not as pictured in the manual as adjacent to the fuel tap which is not anywhere near the filter. Made a rookie mistake and ran our Centurion out of fuel, and in process of checking the system decided we best look at the filter and it needs replacing about 100 years ago. Also I discovered the kigass pump on the rear wall of the fighting compartment is only to atomize fuel from the filter and shoot it into the carbs to aid starting, we had assumed it was like the primer on a CAT diesel and it would pressure up the entire system..evidently not! There are actually priming levers on each fuel pump though again I am unclear if they are simply from the filter on or they would allow the fuel to be drawn from the tank...any ideas?

John

[Malcolm Towrie]

John,
Yes, I bought the filter element Grant found for me on eBay in the post above.

I was also missing the canister for the element so I had to make one, but it sounds like you have the complete filter assembly.

Yes, the priming levers on the two mechanical fuel pumps work quite well. If you can't feel any resistance on the lever, crank the engine over a bit to get the pump arm off the lobe of the cam and try again. Usually one of them is off the lobe and will pump. You can hear the fuel sloshing into the carbs when they are pumping.

They're are a diaphragm pump so they should easily lift fuel from the tanks but only if the check valves in them are in reasonable condition. I had to remove the pumps and clean them so I dismantled the check valves and cleaned them as well.

I noticed after a test run where the engine got up to full temp, and was then not run for a while, it would take a lot of priming to get the carbs filled up again ( to avoid prolonged cranking). I wonder if the hot location of the carbs down in the valley evaporates the fuel quickly after shutdown.

I fitted a fuel pressure gauge in the common supply to the two carbs so I could see when the carbs were full and the lines were pressurized while priming. Good troubleshooting tool for fuel supply and fuel pump problems as well.

I'm using the long range fuel tank hanging off the back of the tank as the main tank, which is rather a long way away and may require much pumping of the hard-to-access priming levers, so I'm considering installing a priming tee connection through the bulkhead where I can hook up a Mityvac hand pump for filling the lines at least up to the filters after prolonged storage.

Regards,
Malcolm

[Robin Craig]

Malcolm can you please post a picture of as much of the fuel filter head as you can please.

I really deeply suspect there is some commonality from elsewhere.

[eddy8men]

john the ki gas puts atomized fuel through jets into the inlet manifold. pump it 3 times and press the small brass button underneath to operate when it's really cold.

[Malcolm Towrie]

Originally Posted by Robin Craig

Malcolm can you please post a picture of as much of the fuel filter head as you can please.

I really deeply suspect there is some commonality from elsewhere.

Robin, I agree. As long as the fuel filter can handle the flow of about 250 litres per hour associated with max power of 650 HP and a horribly rich AFR of about 11:1, it wil do the job.

For any Cent with the original 1/2" tubing (which is a reasonable size to supply 650 HP), it would be good if it had 1/2" tubing connections, and even better if it had the option of the male half of the original vintage UNN BSP fittings used, which had a nut and a nipple soldered to the end of the 1/2" tubing.

I'll post some photos of the filter and the fittings.
Malcolm

[jdmcm]

Thanks Rick, initially I thought that pump would be for priming the entire system but know I now better.

Malcolm my filter is also a Tecalemit, so I will track a few down. My LH fuel pump has some resistance so it feels like it will pump up, any idea how long that should take? I had the filter canister off and was hoping to have fuel beginning to drip from the filter head, but I quit before this occurred.

The manual states to start the APU and then it will fill the filters, but as we have never had the APU running yet, I was hoping for another angle to get fuel to the filters. Our Centurion only has the rear LR tank, all others have been removed. We had success before putting air to the filler on the LR tank and it seemed to push the fuel to the carbs easily, but this time the trick did not work, maybe now with a clean filter we will have success.

Perhaps the one way valves in the fuel pumps are faulty and allowing the fuel to leak back to the tank and lose it's prime. Be nice to mount a pair of spin on filters on the engine compartment firewall, primary with a water separator and a secondary to the engine

[Malcolm Towrie]

John
Since you emptied the carbs, the filter, and the line to the LR tank, it will take a while to fill the carbs again even if the pump check valves are good, I'm guessing 50 strokes?

The pumps suck fuel from the tank so you won't get any fuel flowing with the filter canister off because you have a huge vacuum leak!

I suggest installing a tee in the fuel line downstream of the filter so you can temporarily connect a handheld vacuum pump like a Mityvac to suck fuel from the tank into the filter. Or you could remove one of those nice brass knurled vent plugs from the top of the filter, drill it, and solder on a connection there.

Putting air pressure to the tank to push fuel to the filter may not be working now because there in a vent on the LR tank, that strange rhomboid shaped block sitting at the rear of the tank cover. It has small vent holes on the underside. I managed to get the tiny Allen screws out (I think I used heat) and remove the vent and found the air passage underneath completely blocked by sand and dust. When you applied air, maybe you blew a similar blockage out.

I don't think bad check valves in the fuel pumps will allow flow back into the tank because the tank outlet is it at top of the tank and the carbs can't drain and the fuel pumps are much lower so the fuel won't gravity flow to the tank.

Did you take the tank top cover off? The standpipe going down into the tank had rusted away about 6" from the bottom on ours. I soldered a new section on to get the pipe extended back down so it fitted inside the fine mesh screen at the bottom of the tank. The screen is accessed by removing the smaller cover on the underside of the tank. The bolts on the tank are all SAE, not BSF, in case you hadn't noticed!


Malcolm

[Malcolm Towrie]

Originally Posted by Robin Craig

Malcolm can you please post a picture of as much of the fuel filter head as you can please.

I really deeply suspect there is some commonality from elsewhere.

Robin,
Photo attached. Let me know if you need more.

Malcolm

20190921_194348_resized.jpg

[Robin Craig]

Malcolm that is a new beast to me. Let me digest that for a day or so.

[eddy8men]

john i also ran it dry and it was a real to get it primed again. trouble is i can't remember how we did but i'm fairly sure we cracked a pipe union before the pump and sucked it through