Cleaning the fuel system

[bobh]

I would welcome any advice on giving the fuel system a thorough clean out on a 1964 Three Litre Sedan. A mechanic applied an additive which he said would deal the the "bad petrol" that was present after a long period of inactivity, but it is still spluttering and loosing power (although never quite stalling!),

[petervdvelde]

Underneath the car you find a plate fitted with 3 small screws. If you removed this plate, you find a fuel tank draining screw.
I would also remove the 2 screws near the pipes and pull it out. You then see a filter which could (partly) blocked. Best is to remove the entire tank and flush it

Peter

[bobh]

Thanks Peter - I'm starting to think I will have no choice but to drain the tank - pity I did not decide this before filling it! Now I need to find out how to dispose of 60 litres of petrol in the ACT! 

[petervdvelde]

Bob,

I am no fuel specialist but i would assume that a mixture of old and mainly new fuel would not cause problems as our Rovers aren't that sensitive. I would first check the filter on the tank, check the float in the carburator for dirt and correct level and the fuel pump

Peter

[bobh]

Thanks Peter. I'm working my way through the issues you mention. I had a look in the boot for the first time to see which SU pump I had (dual or single) and found this! Can anyone tell me who made this / what it is / how to service it?

[johnwp5bcoupe]

They are Facet Pumps see :- FACET

[bobh]

Thanks - much appreciated 

[petervdvelde]

These Facet pumps are fine. I have one on my MGB V8 for years without issues. The fitting looks oke but i have 2 remarks.
As you can read in John's link, it is recommended to fit the pump below the fuel level in the tank as these these pumps don't have a great sucking capacity. Looking at the pictures i assume these are fitted above the fuel tank.
I would assume that the pumps have worked properly so this sucking issue should not be a problem but as the pumps get older it could be an issue.
Second remark is that i don't see a fuel filter. On my MGB i fitted a Facet fuel filter directly attached to the pump.
The in tank filter has rather large holes so fine crab could pass.
I would also remove the tanks filter to check if that is not clogged. On my project P5B there lot of dirt was on the filter

Peter

[djm16]

Before diving in, best to make a diagnosis.

If the spluttering does not stop briefly when yanking the choke out, then it is not the fuel starvation.

If there is a strong smell of petrol from under the hood then the carbs are flooding from some dirt under the float needles.

Have you checked the plugs for oil / carbon? The plug leads and caps for cracking / arcing (best seen at night).

[bobh]

Pulling the choke out when it is misbehaving doesn't seem to have any positive effect at all.

I am really a bit short of a hypothesis actually, this is a bit of a learning experience for me! I have taken the approach of working through both the ignition system and the fuel system addressing things that should be done anyway.

I have replaced the plugs and the coil, but there has been no improvement. The plugs were pretty black (maybe over-rich?). I had thought to replace the HT leads and possibly the distributor cap. Had not thought to check it in the dark for arcing / cracks.

I had thought the carb might be the source of the problem, but was reluctant to take it off and disassemble until I had a refurbishment kit, so I could replace gaskets etc.. This arrived during the week. What are the best solvents / cleaners to apply to an old carburettor?

I still hope to drain the tank, to get rid of the last of the old fuel (possibly > 12 months) and see how much crud is in it, but it is actually pretty well filtered (two inline filters in the boot, for both main and reserve, then another inline under the bonnet between the bowl and the carb) and the distinctive smell I was told was associated with "bad petrol" is no longer evident. 

Perhaps unwisely I have agreed to do a little paid work (hadn't had proper shoes on in 14 months!). Combined with the disruption from the house extension, time for the P5 (Fred) has been a bit limited. Still, having more luck with my 1958 105S (George), which seems to be behaving much better, so might get out to the Terribly British Day at Queanbeyan tomorrow (if the rain eases up - over 80mm since 4:00 yesterday afternoon and more to come ).

[Phil Nottingham]

The carb diaphragm will be failing and the economiser drillings will be blocked which will give poor running. As will sticking dashpot piston. Cellulose thinners will remove the gum that causes endless problems.

I assume you have replaced the dizzy condenser?

[djm16]

I really would not touch the carb at the moment. Your problem sounds more like the spark department. Start by pulling all the plugs, attaching the leads, and cranking the engine. You are looking for a small bright blue spark at the tip of each plug.

[bobh]

Thanks guys - I really value the input. The car is running electronic ignition of long standing (pertronix), but i definitely will get under the bonnet in the dark to check for any spark leakage. I think replacing the distributor cap and the HT leads is worthwhile regardless, so will push on with both tidying up ignition and fuel systems. 

[bobh]

First longish run (25 minutes or so) in the MK II 3 Litre since removing some ugly fuel filters that sat between the pump and the tank in the boot. I had overlooked these and there was a reasonable amount of sediment and evidence of poor flow. The car ran smoothly and without hesitation throughout - hopefully (this) problem is solved! Love the way the car runs and handles - smooth and nearly silent except for wind noise at 55 mph - also handles quite nicely (compared to my P4!). Visited some of Canberra's premier littering sites - including Point Hut Crossing on the Murrumbidgee River

[petervdvelde]

good to hear the problem has been solved!

[bobh]

Once again the optimism bias set in. At least I am now much more certain of the problem! With the rear filters removed and a new filter up front, car ran well for perhaps 25 miles before the front filter started clogging up. At least everything else is working OK, and I can see what is coming out of the tank - which is a scary brown mess. Filter seems to be doing its job, which is a good thing, but a new filter every 25 miles is a bit of a bother. So I should drain and clean the tank. If I am going to do that, I should probably treat the tank to prevent / reduce prospect of future rusting / contamination. I would suggest this problem is fairly recent, as there are no leaks and this wasn't a problem prior to the car sitting for twelve months recently before I bought it.

Options I am considering are:

• drain and remove tank. Take to specialist who will split the tank, sand blast the interior, reweld and seal it with a KBS coating (http://www.kbs-coatings.com.au/product/gold-standard-tank-sealer) - cost $700; or
• drain and remove tank and apply KBR (http://www.kbs-coatings.com.au/product/auto-fuel-tank-sealer-kit/) or POR coating (http://www.ppcco.com.au/por19.html) myself - cost $120 - $150.

While I quite like to option of doing it myself (satisfaction + cost), cleaning the tank seems a messy process with a lot of product I don't necessarily want to pour down my drain or have run off into my garden. If I don't get it right, the problem could recur. If I go the professional option, I have (probably) a higher prospect of a lasting solution, less mess but higher cost.

Any views from the group, or experience with POR / KBS coating would be appreciated.

[Phil Nottingham]

Remove the tank - swill out and take it from there.  Tank liners may not be compatible with modern petrol so beware

[bobh]

Thanks Phil. Both POR and KBS coatings appear to be suitable for use with modern fuels. I think you're probably right - first thing is get it out and have a look. However, I find it hard not to start planning the next step! I would still be keen to hear from anyone else who as used either product 

[djm16]

I agree with Phil. When you pull the tank you will also get a good look at the fuel pickup. Mine has a fine brass gauze mesh over it to keep out the larger particles.

When you are doing your swilling, you could add a pound or so off assorted steel nuts to held abrade loose corrosion. Use steel so that you can fish them out again with a magnet!

Beware, you may find the tank corroded to near leaking.

[petervdvelde]

Any views from the group, or experience with POR / KBS coating would be appreciated.[/quote]


The tank is steel but the inside is coated with tin or aluminum so normally you would not find much rust inside. Recently i removed the fuel gauge sender from a tank and was pleasantly surprised that i could not find rust. A light flush was enough to have a nice clean tank. So i doubt you need such a coating

Peter