Monday, January 14, 2013

Aiming

As I mentioned in my last post, the difficulties with spark plug replacement on the Type4 engine are numerous. Angle, axis, access, occlusion, visibility...everything is stacked against you. After my first experience removing a single plug and then having to take a week to research, buy, and install corrective hardware, you can imagine I wouldn't be too thrilled with what the other three cylinders were going to yield.

I wasn't surprised when 2 out of three went hysterically awry.

But first, some good news to temper the hilarity of watching this engine continue to nibble chunks out of me.

I came back two days after installing the time-sert into the #3 plug bore, and backed the 19mm long-reach plug out of the bore and installed my compression tester fitting. With a charged battery, I turned the engine over five revolutions. I'll admit that I was nervous about tightening down too much on the compression tester threading...what if it got stuck? But there were no problems getting it back out and I was thrilled to discover that even with the moderately loose installation, I got 100psi on the cylinder! Woohoo! This is about 20 lbs under what the engine would have run new, and very good for an engine of its apparent age, wear, and long disuse. The 19mm plug went back into place and I was relieved to move on from the #3 cylinder which had caused me so much grief.

Right behind it, #4 (left, rear) and I was relieved that it was so much closer to the back door of the engine compartment. Easier access, right? It was. Right up until the moment when the old plug I was removing dropped out of the socket and down into the engine. By 'down into' I don't mean into the engine internals. It was now trapped somewhere between the engine mantling over the head/cylinders, and thoroughly out of view. This is the 'plug eating' behavior I had been warned about. There is an old gag among Bus people that a guy inherits a bus that his uncle could never keep running. When he decides to rebuild the engine, he pulls it out, and when he removes the mantling, a dozen unused spark plugs fall out on the ground. Uncle never could get the hang of getting those plugs in.

Now I know how uncle feels. Because I put the new Autolite 455 into the socket, and upon attempting to install it, the new plug fell out of the socket (you install the plugs vertically) and down into the same abyss. I lucked out: my inspection mirror (looks like an over-sized dental mirror scaled for an elephant) has a magnetic tip on a telescoping end. I extended it and probed around blind in the hole and finally latched on to something, hauled it carefully out. It was a new plug. A new (though dirty) Bosch Platinum. I went fishing again. This time I came up with the Autolite which I had lost down the pit. I was wondering if I stuck the magnetic tip down there again if I might pull up Jimmy Hoffa's union badge. I never did find the used Bosch copper core plug that had been installed and had fallen out of the socket.

This socket is specifically designed to hang on to spark plugs; it has a rubber o-ring inset inside it which makes a nice friction fit for most plugs. I put the Autolite back into the socket, and tugged on it. Solid. I maneuvered the socket back into place (distance, axis, axis, offset) by dead reckoning and bone conduction  up the extension, and felt the threads click into place, turned it down smooth, snug-n-a-tug. Pulled on the extension to release the socket and leave the plug....

The socket came loose from the extension. All I drew back was the bare stub. Now the socket was hanging on to the plug too well. Much wiggling and swearing later, I had the socket retrieved, stuck back on the end of the extension. Well, at least I had run out of ways that I could get bit:
  1. I've had the plug come loose from the socket and drop into the engine.
  2. I've had the plug refuse to come loose from the socket and left the socket on the plug.
How wrong I was. I moved over to the #1 cylinder (front, right) and had no trouble, but when I was down to the #2 (rear, right) I discovered the missing possibility: 1 and 2 together. A tug on the extension caused the old plug to come out, but the socket did not smoothly slide out of the access hole in the mantling; it caught the edge, and this specialty socket came off the end of the extension and the socket with the old spark plug fell into the void under the mantling. They may have fallen through a space-time rift, since ten minutes of probing with the magnetic end of my inspection rod and my most creative swearing did not draw it back into this world.

Call it a moral victory. I stopped at Autozone the next day and bought what I can only describe as the perfect tool: a 13/16 spark plug socket permanently locked on its own extension with a universal joint in it, and an embedded rare-earth magnet to hang on to the spark plug. If I lose another plug to this engine, it won't be for lack of the right tool.

The #2 plug installed swimmingly. With the injector seals arrived, installed and the injectors bolted back into place, all that is left is to reconnect the fuel ring, pressurize and hope the engine lights. Because I'll running out of ideas of what might be interfering with this engine starting now.

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