Air-Cooled 911 Back in the Shop

The other day, my husband took our air-cooled 911 (964) in for preventive maintenance again. This time, just like last time, he asked the nearby shop, Be-Force, to handle the work.

I asked him, “Wait, didn’t you just have the air-cooled 911 serviced about two months ago? What’s going on now?”

Well, there’s no major trouble or anything. I just want to do preventive maintenance so we can confidently take it on long-distance grand tours anytime. This time, I wanted to replace the distributor belt and fix an occasional strange noise coming from the rear blower fan.

That was his explanation. I see…

What Was Serviced on the Air-Cooled 911

The air-cooled 911 was back from the shop in about a week, and my husband picked it up again. The maintenance work ended up being:

• Replacement of distributor belt, rotor, and cap
• Replacement of the fan and motor inside the rear blower fan
• Elimination of noise from the driver’s door
• Tension adjustment of various belts

I asked, “By the way, what exactly is a distributor? And what’s a blower motor? What happens when you replace them?”

First, the distributor (often called “desubi” in short) is a device inside the engine that sends electrical sparks to each cylinder at the right timing to ignite the fuel. If the electricity generated isn’t sent to each cylinder at the correct timing, the engine won’t combust properly, so it’s a crucial part.
The 964 has twin plugs, meaning each cylinder has two spark plugs. So, it needs to send electricity to 12 plugs (6 cylinders × 2 plugs) at the right timing.
To match this, the 964 actually has two distributors connected together, forming a shape like two distributors joined side by side.
There’s a small belt connecting these two distributors, which synchronizes their ignition timing. If this belt deteriorates and breaks, the ignition timing will be off, causing loss of engine power or, in the worst case, misfiring that can damage the engine.

Porsche 964 Distributor

That’s how he explained it. Well, I don’t know much about car mechanics, but I got the gist. I asked, “So, you replaced the belt because it looked like it was about to break?”

No, it wasn’t about to break or malfunction. But looking at the maintenance records, the distributor was completely replaced at 25,000 km back in 2001, and since then, it hadn’t been replaced for over 40,000 km in 18 years. So, as preventive maintenance, we decided to replace it.
Actually, the belt wasn’t that worn out, but the rotor and cap that distribute the electricity were worn, so it was better to replace them. (By the way, replacing the entire distributor is quite expensive.)

Porsche 964 Distributor Belt, Rotor, and Cap

I see. Then I asked, “What exactly is the blower fan?”

I don’t know the official name, but there’s a fan that pushes engine heat to the heat exchanger to warm the heater. Recently, sometimes it makes a loud “gar” noise. It doesn’t affect driving, but it’s unpleasant, so we had it replaced.
Replacing the whole unit would cost about 150,000 yen just for parts nowadays, but this time we used aftermarket parts for the motor and fan to keep costs down.

Porsche 964 Rear Blower Fan

The total cost for this inspection and maintenance, including parts and labor, was about 199,000 yen. He said it was a very reasonable price. After the maintenance, when he actually drove the car, he said the air-cooled 911 felt even better:

Maybe because we replaced the distributor rotor and cap, the engine’s pickup and acceleration feel noticeably improved. Also, fuel efficiency improved a lot. I haven’t measured it precisely yet, but I’d say it’s about 10% better.
The old cap and rotor were quite blackened and worn, so with new parts, the electricity probably flows more smoothly to each cylinder.
It’s really smooth now, and the more we drive this air-cooled engine, the better it feels. It’s quite different from when we first bought it.

He said that. Recently, I’ve been writing a lot about maintenance and upkeep costs, but for classic Porsche models like the 964, especially, regular and thorough maintenance is essential.

Wow, cars sure are expensive! lol