I recently noticed a black sticky stain on my concrete under what looks like a small sump connected to the bottom of the fuel tank. There was a drain plug at the bottom that was leaking. I removed it and drained the tank, there was a black sludge that came out initially. I can only assume that it was unleaded fuel additive that built up over time. Looking at a s.g. barrett web page it seems to indicate that there is a filter of some sort mounted in the small sump but I am not sure how to get at it. Does anyone know if there is a filter and if so how do I replace it.
Hi,
Yes there is and that whole sump should come off IMO every 2/3 years, it’s amazing how much crud/mud/sand/sludge can end up in there.
It has normal threads and a rubber gasket up there, pretty much the same setup and same seals in most Jaguar fuel tanks 1949-1987. The older ones had a brass mesh filter in the sump, later ones a smaller white nylon/plastic filter. Brass can be cleaned and reused, the plastic one should be replaced with a new spare.
If it has not been opened in 10-30 years it may take sone effort, normal threads, opens counter-clockwise. Good luck!
Cheers!
If your car has the familiar brass gauze filter, as on the mk2s etc, these cost about 75 pounds to replace.
You might like to check out my post in the Saloon section, about a stainless steel replacement for a tenth of the price.
My sump wouldn’t come off with a breaker bar and a three foot pipe. It looked like it was going to twist off at the tank so i gave up and went through the top to clean everything up and replace the filter.
Welcome to the J-L Forum!
The filter is at the end of the pick-up tube which comes out when you remove the big plate on the top of the tank:
I cut the end of the pickup tube a bit shorter than original in the hope that it would be less likely to pick up the junk that accumulates in the bottom of the sump.
No, it wasn’t: “Unleaded fuel additives” don’t accumulate in tanks. Those additives get passed through the fuel system, in through the engine.
It was much more likely just rust, dirt, and accumulated scale. Happens to all cars after for five decades.
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What happens with E10 is that the alcohol absorbs moisture from the atmosphere. Over a winter layover, phase separation results in the alchohol/water mixture sinking to the lowest point in the system and there doing some mischief. What’s accumulated in the bottom is a blob of corrosion byproducts.
The screen at the end of the pickup has to be a low-efficiency screen, not a “filter”. It’s there just to block gross bits that could clog the pump, the fine stuff is picked up by the fuel filter at the bulkhead to protect the carb. Increaing the efficiency of the tank screen runs the risk of vapor lock, so be very judicious with shade tree upgrades.
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So it would seem like a good idea to drain off some portion of this lower level fuel before bringing the car back to life. Any idea how much water is accumulated on say 8gals of fuel being left in the tank?
I’ve said this before: My new winter plan is to disconnect the fuel line and run some 40:1 small motor fuel through the carbs. This fuel is non-ethanol fuel with a little two stroke oil, sold in Home Depot by the quart or gallon. When I open it up for spring, I’ll pump a few oz’s of fuel out of the tank before reconnecting everything. Simple.
As to how much, you can actually test your fuel to determine how much ethanol is in it. I don’t think it’s necessary to know exactly, as you can eyeball what comes out. Just stop when you run out of gunk.
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That sounds like a simple solution to my problem, thanks
Good idea, sorry, no idea re. the water content
You may be right. The car was repainted/restored by a previous owner. Perhaps dust and rubbish got inside then.
That is a good idea, will do that and clean out the tank at the same time.
thanks for the advice - will check it out.
Pull the fuel hose off the carbs, funnel it into large gas cans. Pull the positive lead from the coil, turn the ignition on (no cranking) and your faithful SU fuel pump will empty your tank into the gas can(s)
Your fuel sump will now have 2-3 inches/ ounces of fuel in it. Remove the sump. Dump it in a bowl (HF magnetic parts bowl is perfect) and marvel at the debris.
Once a year clean out will give you happy motoring, unless you get unlucky at an old gas station.
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what a great way to do it - thanks.
It’s best to leave the sump alone. They are made from black iron with brazed brass ends. Quite fragile after many years.They make sumps with a drain plug, 3/8" bolt. You’re always supposed to leave a tank full. If you’re worried about water throw a half gallon of methyl hydrate in the tank. It breaks up water. You could treat it like a boat. Buy an additive for phase separation. If you leave the tank dry it could end up looking like mine in the picture.
This one sat for 15 years and actually had a gallon left in it. I bought a new one but it’s about 5 pounds lighter.
Thanks for your information Ric. That tank looks awful, I will have to empty mine and hope for the best. Did your new tank have s sump with it or did you have to buy it separately? What country are you in?
Doug
Methyl hydrate, methanol, has the same effect as dding more ethanol. It doesn’t “break up water”, it causes the very thing you’re trying to prevent. It’s useful as gas line anti-freeze in winter, that’s about it. I need to see some proof that fuel storage additives actually work. The deposits in your tank are lead, that won’t happen with modern unleaded fuels.
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New tanks don’t come with a sump. I bought one and I will have to thread a bolt into it as a drain plug. I’m in Canada so a tank that starts out as 475 US ends up at $900 delivered to me. Unfortunately it had a dented corner and the shipping costs make sending it back unreasonable. Putty it up and move on.