It was chilly Saturday morning – 39 degrees. This is the coldest temperature we’ve seen in a long time. Donna found a free boot camp type workout group at a nearby school. She walked to the school while I wrote yesterday’s post. We had cloudy skies and rain showers off and on, broken up by brief periods of sunshine. We see fresh snow on all of the hilltops around us.

Snow on the hills

While Donna was at her workout, I watched the Moto GP qualifying for the race in Mugello, Italy. The Italians were cheering as their hero, Valentino Rossi, took pole position for today’s race.

After the qualifying, I walked over to the office to see if my package was delivered. They told me the mail had come, but all they got was junk mail, no packages. This wasn’t what I expected to hear. I e-mailed the shipper and he sent me the tracking number. The USPS tracking site showed the package delivered at 10am. I went back to the office and was told it wasn’t there and I should go to the post office down the street. It was a short walk.

I gave the tracking number to the clerk at the post office and told them the package wasn’t delivered as shown. They looked up the record and said their carrier scanned the package at 10am and left it in the mailbox. They tried to phone the mail carrier, but she was probably driving and didn’t answer. They took my cell number and said they would call me once they talked to her.

I walked back to the RV park office and told them what I was told at the post office. The guy in the office told me he walked out to the mailbox when the mail carrier arrived and she handed him their mail – it never went into the mailbox. He took his key and went out to the mailbox and opened it. The package was in there. Apparently after the mail carrier handed him the junk mail she realized there was another piece of mail. She put the package in the mailbox while he thought he already had all of the mail for the day.

By noon, the sun was shining and it was dry out. I’d had enough of sitting indoors and decided to work on the Spyder. The package I received was a set of custom made MSD 8.5mm Super Conductor spark plug wires for the Spyder along with two NGK iridium spark plugs. The original spark plug wires were causing an intermittent misfire on the front cylinder.

As soon as I had the tupperware removed from the Spyder, it began to rain. I covered the Spyder and went inside. Five minutes later the sun was shining again. The fickle weather continued as I worked – I would have 15 minutes of sunshine then a cloud would pass over dropping rain on everything for a few minutes before it cleared up again. I covered the Spyder and went inside five or six times while trying to do the work.

Spark plug wires – which are sometimes called high tension leads – are more complicated than you might think. Wire is wire, right? Well, not so in this case. Spark plug wires can carry more than 40,000 volts. This voltage is delivered to the spark plug every other revolution of the crankshaft in a four-stroke engine. The rise and drop of voltage can create electromagnetic interference (EMI) through induction or contact with the insulation of the wire.

The insulation on the Spyder’s original wire was breaking down. That’s why it would misfire – the voltage would leak past the insulation and arc to the engine case. Original equipment spark plug wires are usually a carbon conductor over a substrate of fiberglass or kevlar fibers wrapped in rubber insulation. This type of construction has high resistance and prevents EMI. It’s also cheap to manufacture. The down side is that the high resistance causes a voltage drop and can weaken the spark in the spark plug gap.

Low resistance gives a hotter spark but will create EMI. A solid copper core wire would give the hottest spark but the EMI that results would wreak havoc on electronic control modules and sensors. Modern engines have lots of electronic controls and need to be shielded. The answer is a spiral wound cable with a magnetic center core. This creates a choke that prevents the EMI, while high quality alloy in the spiral wound conductor provides lower resistance. Of course this type of ignition wire is much more costly to produce. The MSD 8.5mm wires I ordered are this type.

Spark plug wires with plastic heat shielding

The spark plug wires on the Spyder run from an ignition coil for each cylinder to the spark plug at the cylinder head. Some modern engines do away with spark plug wires by mounting ignition coils directly on top of the spark plug. These systems have their faults, but you don’t have to worry about a length of high voltage wire.

This is the spark plug wire that was arcing – shorting to ground and causing a misfire

It took some time to get to the plug wires – I had to remove the tupperware and the airbox assembly first. My efforts were broken up by the showers passing through. It took about an hour to get the old wires off. The original wires were housed with a corrugated plastic cover to shield them from heat.

Old wire and new wire – heat shielding removed

I removed the heat shielding from the old wires and put it on the new MSD wires. I measured the resistance of the wires – I expected the original carbon core wires to have 1,000 to 3,000 ohms of resistance. The wire to the front cylinder is longer than the one to the rear, so naturally it would have higher resistance. Remember, lower resistance is desirable as long as EMI can be controlled. The original front wire measured 6,000 ohms of resistance! This is not good. The shorter rear wire measured 3,700 ohms. By comparison the new MSD wire for the front cylinder measured 113 ohms. Huge difference!

With the old wires off, I replaced the original copper electrode spark plugs with NGK iridium electrode plugs. These plugs provide a fat, hot spark and will last at least twice as long as the originals.

Spark plugs

I coated the threads on the spark plugs with a special heat transferring anti-seize compound. This will make them much easier to remove next time without risk of pulling the threads out of the aluminum cylinder heads. I also put a thin coating of dielectric grease in the plug connector on the end of the spark plug wires to seal them and make them easier to remove as well.

New wires with heavy duty insulators at the coil end

I test fired the engine – it started immediately and ran smoothly. So I buttoned everything back up and put all the body work back on and took a little test ride. The difference is unbelievable. The engine runs so much smoother. It has to be felt to be understood, I can’t put into words how big the difference in the character of the engine is. Who would’ve thought something as simple as plug wires could make this much difference? With better combustion, I’m guessing fuel economy will improve as well. Job done.

This morning, Donna and I went out for breakfast. We walked down the road to the Lumberjack Restaurant. It was a treat – I had eggs Benedict and Donna had a veggie omelet with a home-style biscuit.

We may have a few more showers this afternoon. I’ll begin prepping for travel. Tomorrow we’ll pull out of here and head to Corning, California – the olive capital.