10 July 2006

Make a Point of Checking Points

Despite some bad weather, it had been a great day for the owner of a beautiful 1950 Austin Atlantic A-90 convertible. On its first outing, the bright red ragtop had taken First in Class and Best of Show awards at the 25th Anniversary British Car Field Days event in Sussex, Wisconsin.

The 100-mile ride from the car show back to Oshkosh had been mostly uneventful. Just north of the Milwaukee area, the skies cleared and what had been severe thunderstorm conditions turned into a bright sunny day. The car was driven home at a nice 50-mph pace and moved smoothly along the freeway with modern vehicle traffic passing safely in the left-hand lane.

The trouble started on the way back to the storage building. The Austin exited the highway, made it up the exit ramp, but stalled and backfired after turning left to cross the bridge over the freeway. As newer cars honked and made dangerous swings around the Austin, the owner struggled to get the engine to start again.

The car finally restarted, but driving the four miles to the clubhouse where it’s stored was no fun. Every stop sign brought additional stalling, sputtering and backfiring. The proud show winner was now definitely in “limp home” mode. Somehow the owner’s driving skill “brought her in,” but when he went to open the overhead door, the engine died one final time. The car had to be pushed back into her berth.

Many bad scenarios rushed through the owner’s mind. Had the freshly overhauled engine’s timing chain slipped or broken? Had a valve or rod bent? Was that expensive rebuilt carburetor a waste of money?

The problem ended up being the breaker points in the distributor. They had loosened and the gap had narrowed to about .002 inches. The owner discovered the problem while using a timing light to reset the ignition timing. Under normal condition with the proper gap setting, the timing light will flash brightly as the points open and close. In this case, the flash was very weak – the owner could just about see it. From this troubleshooting test, he pinpointed the problem and cured it.

Signs of bad points can actually be spotted by using only a simple clip-in-your-pocket type spark plug tester that sells for a dollar or two in most auto parts stores. If you use one of these tools to test how your spark plugs are firing, bad points will show up when you get flashes over all of the plugs that are regular, but low or uneven in intensity. This is a sign that the time has come to remove the distributor cap and reset, re-file or replace the points.

Breaker points are reset by measuring the gap with a feeler gauge and adjusting small screws until the gap is correct. The screws are very small and easy to lose, so work very carefully. Follow the procedures in your factory shop manual or a general repair guide to make the adjustment. It’s very simple.

If the points have pits or build up on them from an incorrect setting or over-use, it may be possible to file them smooth with a special point file. They have to be smooth so the gap will be uniform. Re-filed points may work for a good long while, but a need for points to be re-filed is a sign that you should start scouring flea markets for a new set.

Most classic car owners will want to put a new set of points in right away. These assemblies were made by many companies years ago and are still being made for the reproduction parts industry today for certain old cars. Quality counts, so stay away from very cheaply made contact points. Get the best ones you can find, even if they cost a few dollars extra. Parts manufacturers often offered a choice of standard or heavy-duty points. Get the heavy-duty type if you can.

If you put in new points and still have the signs of bad points, you may have a corroded rotor tip, corroded distributor cap electrodes, a cracked cap, a cap that is dirty or coated with oil, a bad condenser or a bad coil. However, in 90 percent of the cases of “sudden death” – such as experienced with the Austin – you’re likely to find something wrong with your breaker points.

John “Gunner” Gunnell is the automotive books editor at Krause Publications in Iola, Wis., and former editor of Old Cars Weekly and Old Cars Price Guide.

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