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MG TD TF 1500 - Modern Fuels hurt Fuel Pumps?

One of my other antique cars had its fuel pump die last week. This is the second one in 5000 miles, since the car was restored. Our local expert suggested that it may well be that modern gasoline may attack the traditional rubber fuel pump diaphragms. He has his rebuilt with internals that aren't affected by up to date fuels. I searched the archives to no avail, wondering if this is going to rear its ugly head with the TF. Has anyone had any experience along these lines?
Gene Burgess

Gene - As far as I know, the jury is still out on this subject. I know that something started disolving the slushing compound that I used to seal the fuel tank of our TD some 25 years ago and the only other thing that has been put into the tank has been gas. So far, in my work on the SU fuel pumps, I haven't seen anything that leeds me to suspect that any damage is done. That said, Buren Fuel Systems told me to expect to see some deterioration of the diaphtagms when ethanol is used in the fuel. I guess that time will tell. Cheers - Dave
David DuBois

What made you think that the slushing compound was getting desolved? Plugged filter? Bowl sediment?

Steve Wincze

The new SU diaphram I got has a hard plastic layer in front of the rubber. I think this is to prevent the rubber from disolving. George
George Butz

If the fuel vendors in your area of the country start to use the so called "summer additive", watch out. Its concentration sensitive.
There is a name for this chemical,(forget) and if the concentration is to high it will eat up you old fashioned fuel system rubber components. Several years ago Ford Motor Co did a study on the ppm of the additive. What they found was that all fuels are not equal. the "majors" add it accurately the independents do not. A dose on the high side and it all goes bad.
I have had several incidents of fuel pump gaskest dissolving into mush because of it. Dave D. came to my rescue with the Burlen gaskets and I have not had an issue since.
stick to major brand fuels and avoid gasahol in any form.
Colin Stafford

Steve - "What made you think that the slushing compound was getting desolved? Plugged filter? Bowl sediment?" - Needle valves in the carbs and checks valves in the fuel pump firmly glued shut! Plus sticky residue on the dip stick I use to check fuel level in the tank whenever it rubed the inside back of the tank.

George - "The new SU diaphram I got has a hard plastic layer in front of the rubber. I think this is to prevent the rubber from disolving." - Actually, I think you got hold of an old stock diaphragm from about 5 to 10 years ago. The diaphragms during that time period had the plastic membrane on them. All it did was interfere with the operation of the pump (I always cut them off). Burlen Fuel Systems quit using it some years ago.
Cheers - Dave
David DuBois

I don’t know if this is a coincidence or not, but the gas in my area is not recommended to not be stored for more than 30 days. So this year for the first year I put “gas stabilizer” into the TD tank for winter storage. I also put some into the lawn mower and string trimmer gas as recommended by the lawn mower repair shop. Anyway upon starting the string trimmer up this spring, it would not. After checking everything out, the plastic gas lines from the tank to the carburetor had disintegrated. This product is also used to clean the carberator , by spraying into the throat while the engine is running to clean varnish build up. Maybe it dose to good of a job. I do know I won’t use it next year in the TD. I’ll just go back to driving it every few weeks in the winter with new gas added. John

John - Interesting observation. I recently restored a fuel pump where there was a lot of corrosion on the valve disks and other exposed interior brass parts. When I queried the owner, he told me that he had used Stabil in the tank over the winter. Cheers - Dave
David DuBois

Ethanol has been wreaking havoc on rubber bits for some time now. I have had two rubber failures I am certain are related to ethanol-laced fuel.

The best advise I can give at this point is to replace all fuel hoses and gaskets with modern rubbers, designed to resist the negative effects of ethanol.

Ethanol does not attack rubber directly, but it dissolves the emulsifiers which keep the rubber soft and pliable. When this happens, you develop sudden and potentially massive leaks.
Steve Simmons

This thread was discussed between 27/05/2007 and 30/05/2007

MG TD TF 1500 index

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