Tuesday, July 13, 2010

Muscle Car Tuneups and Diagnostics

ABOVE: Right tool: The OK Spark tool is quite handy. If you do any project car searching, you need this tool. Simply cranking the engine with this tool in place will show you a lot about the ignition system. BELOW: Reviewing the basics: The cap and rotor are the primary culprits for ignition troubles beyond spark plugs. Replacing the plugs, wires, cap and rotor will almost always get it running.

Tuneups and Diagnostics
Jefferson Bryant
Unless you are one of those “hermetically sealed, never driven” musclecar collector types who has forgotten what musclecars were all about, you enjoy driving your car.

The article featured on this page is from the February 2010 issue of Musclecar Enthusiast Magazine.
Click here to read the free digital edition of Musclecar Enthusiast now.
Whether it is a long road trip or just the occasional weekend trip for dinner and a movie, your musclecar needs to run right. In the modern age of computerized engines and fancy tools, real-world, old school tuning has been lost. Unless you remember all the ins and outs of tuning and diagnostics, you may need a bit of a primer. While one page is way too short to get into much detail, I have a few tips and tricks, and a really neat tool that will make tuning much easier.

Engine not running smoothly or not firing at all? Before you get flustered, pick up the Spark Plug Sensor from OK Spark. This handheld sensor not only tells you if you have a spark, but also will tell you if the plug is firing. No more shocks (we have all been zapped by the coil using a screwdriver in the plug wire), no pulling plugs, no guesswork. The tool works with engine running or just cranking. It is a no-touch system, too — you just place the sensor near the plug and it takes a reading. The tool has a “real-time” setting for watching the readings, and a “snapshot” setting so you can attach the clip to a wire, crank the engine and then look at the results, which is great if you are by yourself.

If you are getting voltage to the plugs, but no spark, then your problem lies in the plugs. Chances are you have a few plugs that are fouled or worn, and this tool helps you find the ones that are not working so you can inspect and replace them, saving you a lot of time and headache.

If you are not getting voltage, then the problem lies in the plug wires or the distributor. The OK Spark works at the distributor cap, too, so you can see if you have voltage there. If not, then you have an internal issue.

The first thing to check is the cap and rotor. Pull the cap, and look at the contacts on the cap and the terminals on the rotor. If they are worn, it will be fairly obvious, as there will be a lot of carbon deposits and the terminal contacts will be uneven and show a lot of wear. You can always take them down to the local parts store and compare them to new parts if you are unsure.

Points taken
The next spot of trouble, and one that will really throw a lot of enthusiasts, are the points. Points-style ignitions are reliable, but they do need adjustment and replacement from time to time. Since most musclecars have points-style distributors, let’s review a trick for setting the points.

First, you need to see if the points are burned. Burned points will have an obvious burn mark, accompanied by some pitting on the contact pads. Replacing the points and condenser is fairly easy and in most cases, there is no need to remove the distributor. Setting the points is not hard, but what if you are on the side of the road? In a pinch there is a trick to getting the points back in line. If you don’t have a spare set of points in your travel tool box, keep a piece of 500-grit sandpaper. Use the sandpaper to lightly file down the points, removing the carbon and softening the pitting. This will usually get the points to fire again. Now you need to adjust the gap. A business card or matchbook will get you to the approximate .019-inch gap needed for most points systems. Put it back together, and you have a spark.


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