The MGA With An Attitude

This one started out as a discussion on the pros and cons of electronic ignition, which can be either inherently reliable or inherently unreliable, depending on your point of view. It soon turned to the general discussion of reliability of old British cars, and particularly electrical parts. Most "problems" you will encounter with your MG will happen because it is both old and neglected. The cure for both of these issues is to get the car into good condition once, and then keep it that way through a sensible maintenance program.

At 11:00 PM 4/1/02 -0800, Phillip Erikson wrote:
>".... It's just that I've used the Pertronix setup before in many of my cars, race cars included, and it works very well."

Indeed it does, when it's actually working, which is most of the time. It's just what happens on that one rare occasion when it doesn't work that bothers me. I have heard too many stories about electronic ignition modules of all brands and types which eventually fail and leave someone stranded on the road and sometimes inconvenienced for days before they can get the replacement parts. If you don't mind the cost of two complete sets of parts, and carry the spare set with you at all times, or carry parts to switch back to points if the electronic parts fail, then you will do just fine. And in the meantime you have less maintenance with the electronic setup, which is what draws most people to it. I just happen to be squeeky tight on cash when it comes to long term cost effectiveness, and also short on storage space when I hit the road for weeks at a time. And I don't like the idea of being stranded on the road, so I have a little different slant on this idea.

[You can find a more complete dissertation on electronic ignition in the Electrical section.]

>"Part of the charm of this list is seeing how others differ in their approach to solving problems they share with you."

Sure enough. I just happen to have different operating parameters and demands and expectations than some other folks. Not too many people have driven a 40+ year old car over 200,000 miles, or would take one on a long distance road trip. My number one point in judging reliability is the likelihood of the car getting me home and never being stranded on the side of the road. To that end I don't trust electronic parts as far as I could throw them. If my ignition contact points start acting up (usually worn out of adjustment from neglect) I can generally use a thumbnail to regap the points and drive on, with the opportunity to install new parts later at my convenience.

<SIDENOTE> My 1990 Chevy Lumina has had to be towed off the road twice in the last 20,000 miles due to electronic part failures. The first time garnered a $900 bill for replacement of 6 fuel injectors (including towing), apparently needed every 100,000 miles or so (which is just about equal to the cost of a complete new engine for the MG every 100,000 miles or so). That particular incident occured while my MGA was in the middle of the 19,000 mile Alaska trip (without any disabling incident). No way would I take that (then 7 year old) Chevy on a trip like that where it might have to be towed as far as 500 miles to the nearest qualified service shop. The second serious incident with the Chevy was due to a faulty crankshaft position sensor, only a $22 part, but dead on the road nonetheless, and difficult to diagnose without some computerized instruments. </SIDENOTE>

In general, small electrical and electronic parts have three common modes of failure that account for 99% of all operational problems. Coils wound with tiny wires suffer insulation breakdown and shorting between windings (fuel injectors and other small solenoids and proximity sensors and small servo motors). Any electrical part with a plactic body (most of them these days) can fail from deterioration of the plastic due to thermal stress, which commonly results in a short to ground through a crack in the plastic. And solid state circuitry, especially that which conducts high current (electronic ignition switching modules and driver switches for fuel injectors), can fail from degenereation of the electronic junctions in the heart of the device. All of these failures are related to age and heat exposure, and to some extent vibration.

After about 10 years and/or 100,000 miles these parts will start failing in a predictable manner (statistically speaking), and the more of these parts you have on your car the more often will be the failures. When you have dozens of electronic devices in the car, most of which are related to keeping the engine running, then you definitely are going to be inconvenienced in a big way sooner or later, and much more often as the car ages. You probably wouldn't want to carry a spare part for every electronic thingy in a new car, and the computer equipment necessary to diagnose any failure, so the alternative is to carry a cell phone and an auto club card and resolve yourself to the fact that you will be inconvenienced at some time (probably at the most inconvenient time) and the repair bills will be large. I firmly believe that the only way to make a post 1981 vintage car reliable after 10 years of service would be to replace every electronic part on the car with new parts (restoration sound familliar?), which may well cost more than the market value of the vehicle.

Additionally, electronic parts can suffer from other causes of failure, usually related to abuse or improper installation. With some electronic parts, if you just get the power polarity wrong it can fry the part. The Pertronics ignition module is a good example of this sensitivity. Hook that one up backwards and it can instantly go up in smoke. The end result may be that the part simply no longer works. A more serious result might be a dead short to ground, where subsequently hooking it up the right way can result in a badly burned wiring harness. With some electronic parts a loose or corroded wire connection may only cause it not to work, while some others might get fried internally with the same problem.

In the case of your MG, if you have one electric (or electronic) fuel pump, and you carry a spare or repair parts, and you have one electronic ignition module, and you carry a spare (or parts to re-install the original cantact points and condenser), the failures will be few and far between, and you will have your ass covered when it does happen. For any single day on the calendar the electronic part may be more reliable than the mechanical part, in the sense that the engine keeps running without any maintainance. But in the long run (decades of use) the electronic parts will likely be more expensive to install, maintain, and replace as needed. One key ingredient here is whether or not you pay for the labor. If you get knicked for a towing bill or just a few hours of shop labor at current rates, all economics are down the tubes.

This is one of the charms of an old MG. They are very simple cars with very few electronic parts, so not as much to go wrong. The most persistent electrical problem with my MGA 1500 has been a turn signal that sometimes doesn't blink because of an intermittent relay contact. This particular problem will not affect the later cars, as the MGA 1600 does not have the turn signal relay unit. My MGA has been towed exactly four times in the most recent 15 years and 175,000 miles, twice when it dropped an exhaust valve head and punched a hole in a piston (but not since I started using Stellite exhaust valves), and once when the starter motor fell out, caught the ring gear and broke the crankshaft (loose bolts probably due to deteriorated threads in the aluminum gearbox housing, but not since I started using Helicoils in the tapped holes. The most recent tow was a result of dropping an intake valve and punching out a piston. In this case the valve broke at the keeper groove. This happened three times in one year after installing all new valves (only needed towing once), three different valves all from the same parts order, obviously defective parts.

Other incidences which did not require towing were another broken crankshaft (old age stress failure, driven gently for 40 miles after the break), a couple more dropped valves (driven home up to 150 miles on 3 cylinders), a broken piston (driven home 10 miles with a loud knock), another piston (with 100,000 miles on it) broken at the top ring groove (driven home casually 175 miles), several occurences of damaged con-rod bearings (driven home gently up to 150 miles after addition of two cans of STP in the crankcase), multiple cases of various electrical failures (mostly related to bullet connectors), and lots of other stuff I don't have space to list. The key point here is that in most cases the stock MG can be repaired on the spot or can limp home when required and will not leave you stranded. The primary ingredient in this case is simplicity.

The more complexity you add to a car the more likely it is to fail, and the more difficult (and expensive and inconvenient) it will be to repair. On the extreme end of this scale are the new cars with so many parts (especially electrical parts to make the engine run) that they are a veritable Pandora's box that can open by itself at any time without notice. Your old MG with electronic ignition, by comparison, will be about as reliable as any car on earth, so you can ignore all of my negative comments. Just do yourself a favor and carry a spare ignition module or a set of points for an emergency.

Just for kicks, here is a list of some things that my MGA has never had any problem with in over 300,000 miles of use in more than 40 years:

  • Roll up window mechanism, electric window motor, vent windows
  • External door handle or key operated door locks
  • Backup lights, 4-way flashers, Pop up headlights
  • Starter solenoid, Automatic choke, Electronic ignition
  • Power steering, Power brakes, Air conditioning
  • Overdrive or Automatic transmission
  • Positraction differential
  • Electronic engine control computer and related parts
  • Sunroof, Power antenna, Electric rear window defroster
  • Emissions control components
  • Electrical relays (other than that silly turn signal)
  • Anti run on valve, or fuel cut-off inertia switch
  • Button switches in door jamb, glove box, bonnet or deck lid.
  • Seat belt retractors, elecrtical interlock or warning buzzer
  • Torsion bars, springs or gas struts for the bonnet or boot lid.
  • Well, by now you should be getting the idea. The MGA doesn't have any of those parts. In fact it doesn't have very many parts at all that are not required to make it go down the road. Even the heater was a listed option when new and not standard equipment. The MGA's primary consession to complexity would be the dual carburetors, but then it is a performance part (and MG did happen to own the SU carburetor company at the time of production).

    I have added a few options to my car that have increased the complexity and maintenance requirements slightly, but mostly in the interest of performance:

  • Large front anti-sway bar (replace poly bushings every 100,000 miles)
  • Oil cooler (adds 10 minutes to R&R the engine)
  • Mallory dual points distributor (was cheaper than Lucas replacement)
  • 40,000 volt Lucas Sport Coil (great spark, same maintenance)
  • Halogen headlamps (visibility & safety, same maintenance)
  • Optional windscreen washer (original type, safety feature)
  • Battery cut off switch (reduces maintenance time)
  • Single 12 volt battery (reduces maintenance time and parts cost)
  • Intermittent wiper control (safety feature, currently on probationary test)
  • Slightly warm camshaft (20,000 exciting miles so far with no problem)
  • Spin-on oil filter adapter (reduces maintenance time)
  • Coolant recovery pressure cap and fluid bottle (no dribble and no bother)
  • K&N air filters in original housings (better filtering, same maintenance)
  • DOT 5 brake fluid (reduced cost of replacement parts)
  • Aftermarket electronic fuel pump (reduces maintenance)
  • Trailer hitch (no maintenance, just handy, and a little added weight)

  • Bottom line is that my MGA is about the most reliable car that I have ever owned, and the least expensive to operate for many years running. I have no hesitation about driving it 1000 miles or more on a minute's notice for an interesting club event, or seriously autocrossing it (regularly) on summer weekends. I take it on many long road trips (500 miles does not count, only a day trip), 13,000 miles around the country in 1989, 19,000 miles on the Alaska trip in 1997, and 3800 miles in 10 days for spring break to Key West in 2002. Just get the car in good condition once, and then give it whatever it wants for daily maintenance. It helps a lot if you assume the frame of mind to treat it like a permanent member of the family with the intention of keeping it on the road forever.

    Best regards and many happy miles of motoring,

    Barney Gaylord
    1958 MGA with an attitude

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