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MG MGA - Unreliably Reliable

Ijust got my January 2006 issue of "Automobile" and starting on Page 74 is an article about several British cars and their reliability over the years. There are some good comments and pictures on the MGA and a few other British cars.
N. Wessely

Hi. After replacing known problematic parts, my MGA was reliable enough to drive from Ontario Canada, to Nova Scotia Canada and back. (Several thousand mile journey through largely unpopulated forest) Problematic parts replaced were the stock SU fuel pump (replaced with a reliable electronic pump), Lucas points and condensor, (replaced with American made Blue Streak brand components) and Standard SU carburettor needles and seats. (replaced with Grose Jets) Cheers! GLenn
Glenn

Glenn,
I really can't see how a stock SU fuel pump can be considered problematic. In 40 years of driving MGA's I've never been stranded by one. My original is still intact (points excepted) and in place. Maybe I'm just lucky.
Cheers,
GTF
G T Foster

Hi GT. I don't know, perhaps you are just lucky. I know numerous British car owners that have had nothing but trouble with their stock, points driven SU fuel pumps. My original pump started having points problems while the car was being restored. You know, whack the pump and it runs for a while, then quits? Having previously owned a 67 MGB that just about drove me nuts with SU fuel pump problems, I got a brand new transistorized facet pump for my MGA. It has run for 25 years, with absolutely no problems, and still works great. Even Brand new SU fuel pumps in my old MGB lasted only 4 or 5 years, and would then start having problems. On disassembly, they were internally very clean, but had badly deteriorated electrical contacts, and much metal transfer between the points. New points were installed. Thinking the condensor was faulty, a new condensor was installed at the same time. Despite my carefully rebuilding a few SU pumps, they were still quite problematic after a few years of use. So I have sworn off SU points style pumps, and use modern electronic pumps with no points or condensor. Cheers! GLenn
Glenn

I have to go with GT on this one. I've never had an SU pump leave me on teh side of the road. Once I had one become intermittant but the beauty is that SUs don't typically just die. They give you warning which is what mine was doing. I've had nothing but good experiences with SU pumps in six MGs over the past 16 years. :)
Steve Simmons

I too have had little problem with the MG fuel pump. The problem I have is getting a GM, Chrysler or Ford fuel pump to last more than 10 years!
Chuck Schaefer

I had many problems with my original SU fuel pump back in the '60s & 70's, mainly related to the rocker assembly for the points (see http://home.mindspring.com/~mga1600mkii/mga/id4.html) I replaced it back then with a Bosch. During my recent restoration I inadvertantly ended up with a new "original" type and as yet don't have enough miles/years on it to form an opinion, but I'd expect the reliability to be less than the electronic versions.

- Ken
Ken Doris

In 1975 westbound on I-70 in eastern Utah my fuel pump died at night on that lonely stretch of desert. A Ford Cortina of all cars pulled me to Green River where the car was left in a gas station lot. The Cortina took us on to school barely in time for class, one long night. I ordered a fuel pump from the local parts store and rescued the 57 MGA coupe a week later. Besides the broken crankshaft this was the only time it left me stranded in 3 years.
R J Brown

Hi folks. It seems that with our MG's and other British cars, people seem to have vastly different experiences sometimes. So far, people on this forum seem to have had very positive experiences with their SU fuel pumps. Years ago, both my Austin Healey 3000, and 67 MGB were plagued with SU fuel pump problems, and not because of dirt in the fuel system! Some people are unlucky in love. Perhaps I am unlucky in SU fuel pumps, although I do know several other people who share my sentiment, and wouldnt take an SU fuel pump as a free gift! NEWS FLASH: for Ontario Canada readers: A MAJOR snow storm is blowing in from the west. Heavy snow and strong winds are likely. Time to garage your MG toys, if you are still driving them folks! Merry Christmas one and all, Glenn
Glenn

Oh goody. I'll get to try out my new snow blower!
Andy Bounsall

I'm just wondering whether the different degrees of reliability people are experiencing with the SU pump is something to do with the methods SU have used in the past to dump the inductive energy in the solenoid on switching. If no method is used, as on the very early SU pumps, then this energy is dissipated in the arc created at the points on switching, increasing the temperature and therefore removal,transfer or oxidation of the metal of the points. Later on, SU incorporated a condenser wired across the points to help absorb some of this energy and extend the life of the points. Later still they replaced the condenser with a diode across the coil which gives an improvement over the condenser. I don't know the dates of these improvements but if someone has a pump, say, with a diode in it this could explain the improved reliabilty compared with someone having an earlier version of the pump. I have recently dismantled my pump, supposed to be 1960, and there is neither a condensor nor a diode in it! Perhaps other peoples pumps are so deprived? If someone has regular trouble with their pump it might be worth checking whether they have a diode in and if not put one in. Even if there is a diode there it might be worth assuming it has pinged and replacing it.

When you think about it switching inductive loads on cars of this vintage is always problematic and leads to unreliability. Just think how often the ignition points have to be cleaned.

Also the Lucas Windtone horns have problems caused by inductive switching but as these are not used too often their failure is infrequent and even then they don't stop the car. I was cleaning up a couple of Windtones I took from an early 1950s Riley recently to put in my 'A' and I noticed that Lucas had built in a resistive dump for the coil energy whereas in the later MGA Windtone (1960) there is no dump used at all! This was a retrograde step but I suppose Lucas were trying to save a bit of cost.

But when all is said and done do we really want a car that is 100% reliable? When you think back and try and recall memorable car journeys they are always the ones where something went wrong with the car. You don't remember the journeys made today in modern cars because they are so dull and boring, just like the cars themselves.

Cheers Mike Moore
m.j. moore

This thread was discussed between 14/12/2005 and 15/12/2005

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