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MG TD TF 1500 - Gas line filter

As I was cruising along on my creeper today I noticed the fuel line filter I installed under the gas tank. It has what looks like rust particles and some other crude collecting in the bowl.
I elected not to remove the tank when I got the car. The lining looked good and I had so many other things to do. I put the filter in just in case and am very glad I did.
I prefer my rust in the filter much more than in the carb or engine.


Mort 1950 TD1851 Möbius

Mort,
I have one just like that on my TD and I have it on the line coming up the firewall before the fuel pump. That way I can check it out every time I open the bonnet. I usually have to clean it out once a year. I use the same filter on my other cars and I, like you, save the carbs and fuel pump.

Cheers, david
David Honness

David,
That's a great idea for keeping tabs on it. I have a backup fuel pump just forward of the rear axle. I wanted to keep that clean also. Hence the filter in the back.
Mort 1950 TD1851 Möbius

Mort,
Good idea of the back up fuel pump. I just carry an extra pump with me.
Cheers, David
David Honness

In earlier threads concerning filters to screen out tank rust it was expressed that a filter should not be between the pump and the tank as it would burn out the pump I believe some of "gurus" stated the filter should always be on the outward side of the pump ?????
Jon Levine

jon, you are EXACTLY correct. there should be NO filter between the tank and the pump. dave dubois has much info on this in the archives.
david, the filter before the pump will do the exact opposite of what you are trying to prevent. the pumps can pass a lot of debris but cannot tolerate a restricted filter upstream. regards, tom
tom peterson

I have the Moss filter on my car and it has been on there for over 12 years and no problems. it is before the fuel pump. I have run it like that with and without a supercharger. no problems to date.
Tom Maine (TD8105)

Instead of a filter to treat the symptom, why not clean and seal the tank to eliminate the rust problem. A modern day, high efficiency filter will trap very fine rust particles that will pass through the filter screens in the pump and the carburetor, causing no problems with either. The problem occurs when the modern filter traps enough of the fine particles to eventually clog the filter and completely stop the flow of fuel. When this happens, a SU fuel pump will stall in a current on condition and if the power is left on long enough (while troubleshooting for instance), the internal swamping resistor in the pump is burned out. This does not cause an immediate problem - the pump will continue to run just fine, but...with the arc suppression circuit (the burned out swamping resistor), the points will begin to arc excessively, greatly reducing the life of the points. Easy enough to slap a new set of points in you say...well, what do you say when that new set of points burn out in a very short time? This is what happens when the the internal swamping resistor burns out. On the early, low pressure pumps, the swamping resistor is is a fine resistance wrapped around the coil itself and is the only thing used for arc suppression. It wasn't until later years that a capacitor was added to the arc suppression circuit and even then, the capacitor works in conjunction with the swamping resistor to suppress arcing. The swamping resistor is also very difficult to replace, as the coil has to be pressed out of the housing and a new resistor installed. For pictures this damage, see the article, SU Fuel Pumps, Fact and Myths in the SU Fuel Pump Articles section of my web site at: http://homepages.donobi.net/sufuelpumps/ )

For those of you who have replaced the original SU fuel pump in your T series cars with an all electronic SU pump, a burned out swamping resistor becomes even more of a problem. Not only does a stalled pump get the resistor, it usually burns the circuit board. If the owner gets lucky and the board isn't burned, they will find that the pump doesn't work at all once the resistor is gone (I was told this 7 or 8 years ago by one of the technicians at Burlen Fuel Systems when we were over there, and this situation may have been cured by now, but I don't know that as a fact).

It is because of the above information that I recommend against a modern, high efficiency filter being installed between the tank and the pump (you don't suppose that the original people in the MG Car Company knew of a good reason not to put a filter in that position do you?). If you want to put a filter in that position and are willing to monitor and change it religiously to avoid it becoming clogged, then it is up to you (besides, I make good money repairing pumps that have quit working properly). Cheers - Dave
David DuBois

Dave,
What can you seal a tank with now...from what I understood, the Ethanol in gas today is eating away all of the sealant people used to seal tanks...
Looks like you got a little snow your way, can you send it to new hampshire please...the skiing is marginal!!!
Bob Dougherty

"What can you seal a tank with now" Eastwood has a complete kit for cleaning and sealing the tank (may be the same one that Moss carries), that is supposed to hold up to ethanol. POR 15 is also supposed to be very good for the job. I had our tank treated with zinc phosphate a couple of years ago - it will be some time before I can make a value judgement on that.

"Looks like you got a little snow your way, can you send it to new hampshire please...the skiing is marginal!!!" You mean it hasn't arrived yet? The jet stream carried it east almost a week ago. You can have all that we get - we prefer our precipitation to be the kind that runs off :-) Cheers - Dave

David DuBois

David DuBois,I had our tank treated with zinc phosphate a couple of years ago - it will be some time before I can make a value judgement on that.



My tank was treated with zink phosphate also. Probably about 5 years old. It creates an extremely hard surface. Ethanol has not affected it yet! PJ
P. Jennings

I had a small filter like that originally, but on the output side of the pump. I was told it's risky to put the filter before the pump as indicated above.

And, i found that small filter would foul pretty easily and keep the car from running. NAPA has a nice pleated clear filter for like $4 that fits inline between pump and carbies and is much better,

And lastly, do you have the brass screens that extend up into the tank? Those are so fine that I'd be surprised to have chunks the size youre seeing in the line. If not, would be advisable to fit this screens in the tank then put the filter on the output of the pump.
L Rutt

L Rutt, Florida, USA

"And lastly, do you have the brass screens that extend up into the tank?"

Where can I get more information about these screens?
Seems like a viable option until I can re-coat the tank.
Mort 1950 TD1851 Möbius

I think those screens are original to the car.
Moss or abington spares may have them.

Dan H.
Dan Hanson

Moss and Abingdon send the fitting to a vendor who solders the screen on.
Moss has lost their vendor. No word on a replacement.
Abingdon is out of stock but will call me when they come in.

I left a message for Doug at FTFU.

One aspect about this screen is that it is not visible. However if the screen is the cylinder I think it is then it would take several inches of sludge at the bottom of the tank to choke of the fuel supply. At that stage the tank has probably already rusted through.
Mort 1950 TD1851 Möbius

That is true on the screen, It goes up a long way and would take a friggin hellish amount of stuff to plug that off. I have a MKII so I actually have 2 feeds from the tank, both of which are screened this way. Although I only use one pump and one feed at a time with the other as a backup.

I don't get the flakes, what I get is the very fine powder. That is what was plugging my small barrel filter like the PO had. Once I switched to the larger pleated type filter, and change that out a few times, I really have no problems at all since. That was a real bugger to sort out at the time.
L Rutt

Mort
Getting back to the junk in the filter....It is not necessarily from the tank itself....
Many gas stations , today, are pumping all the way down to the bottom of their tanks, sucking up loads of "crap".
Also, if the tanker truck has been to the station within the last hour, or so, all the muck in the tank is stirred up...There is no real way of knowing, so an in-line filter, after the pump, is almost a necessity.
Re the ethanol...In our area, several stations are selling ethanol-free gas...I only fill the TD at those.
Edward
E.B. Wesson

Jon and others,
All my cars have the fuel filter after the tank and before the fuel pump and in over 20 years I have not had a failure in all my driving from fuel. The secret is as Dave DuBois says keep your tank clean. I get very little sediment in the filters but part of my yearly maintance I clean the filters out.

Cheers, David.......
David Honness

Agreed a clean tank is the solution, but until The somewhat convoluted and timely process something should be done. As to the filter in the tank it does work but sometimes too well, I changed out the outlet a few years ago and it came with the brass filter now I can go for about twenty minutes then I clog out. Until I get to the tank next month I put a aplice in the inlet to the pump and when I choke out I go out lift the bonnet split the line and blow backwards like hell, recoonect and go my merry wayyou should see the looks.
Jon Levine

Speaking of a very fine powder in the fuel. If you deal with an older gas station, that has steel storage tanks,(how would you know this), never fill up while the delivery truck is pumping fuel in them. Any fines in the tank and most old steel tanks have them, will stir up and you'll get it in your tank. Forget the station filter system, most stations don't use them. My Bronco got a full tank of the stuff, a fine reddish brown powder, and it took all day to drain and clean the system, including a 4 barrel carburetor. Lost 25 gallons of gas also. Just a thought.
P. Jennings

My rule of thumb has always been to never use a gas station that has the delivery truck on site. No matter what kind of tank there is always sediment and/or water at the bottom and the delivery hose will stir it up. I learned this the hard way years ago more than once.
James Neel

FYI,
I left a message for Doug at FTFU inquiring about the in tank filter.

He never called back but I got an e-mail from Doug,
"A package was shipped to you on 01/25/2012 via U.S. Postal Service"

Doug Pelton
FROM THE FRAME UP ,LLC"

So I assume a filter is in the mail to me. I will post more when it arrives.

Mort 1950 TD1851 Möbius

My thanks to Ed and others for the discussion on service station gas tanks. I had completely left that out of my thinking. I am now possibly encouraged that my gas tank is in reasonable shape. Just doing a visual inspection through the filler cap with a good flashlight, shows me a nice clean coating as far as I can see.
I promise you all and myself to keep the filter clean. I will make a decision about the in-tank filter after I see it.

Thanks again for all your comments.

Mort
Mort 1950 TD1851 Möbius

FYI,

Just a follow up for anyone interested. I got the fuel filter from Doug at FTFU today. The screen sticks up about 1-3/8" from the end of the fitting. As soon as I run my tank down near the bottom I will install it and clean my in line filter at the same time.

Does anyone know if this was an original part?


Mort 1950 TD1851 Möbius

Yup! Here's the one from 'the53'. I'll be re-using it after a bit of cleaning. Bud


Bud Krueger

Mort, looks the same as mine on the 53 TD.
Jim Merz

Here's the one from 'the53' with a scale:



Bud Krueger

The screen is fairly clean, just very fine mesh:



Bud Krueger

How did you clean it, Bud?
Jim Merz

Sprayed it with carburetor cleaner, Jim. Bud
Bud Krueger

I am just going through this process now with 1953 TF which has TD type low pressure pump on firewall. After removing filter from tank, which you could hardly see light through even after cleaning with carb cleaner, I removed sender gauge from tank and found it was covered in varnish. Soaked filter in 'meta kleen' and it came up like new. Hopefully this and flushing loose accumulated rubbish from fuel tank will solve fuel starvation problems.
Already reconditioned carb's and fitted electronic SU pump without success.
Greg King Sydney Australia
G. D. King

Greg,Jim - When I said 'sprayed it with carburetor cleaner' I meant the emphasis to be on 'sprayed'. The cleaner comes with a small diameter red tube that fits into the nozzle. This concentrates them spray over a very fine area. Spraying this back and forth over the filter screen allowed me to remove virtually all of the entrapped crud. BTW, brake cleaner works, too. Bud
Bud Krueger

Thanks Bud, with my car in winter hibernation in the basement, this will be the ideal time to inspect and clean the filter.
Jim Merz

This thread was discussed between 24/01/2012 and 02/02/2012

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