Tuesday, December 23, 2008

Maintenance ...

As we started doing the basic maintenance, we found some common, but easily fixable problems. The ignition system was in need of tuning up. First off, the plugs were shot ... the electrodes were worn down to small tips which resulted in an inferior spark. To add to our ignition woes, the distributor contact points were virtually non-existent! I'll be honest, I'm not very familiar with distributor based ignition systems, but my team mate (and Uncle), who apparently is, had never seen such a worn out cap and rotor. The worn out cap and rotor created a larger gap for the spark to travel to in its quest to find the right engine spark plug. These larger gaps in the plugs and distributor were definitely not helping.

Reluctantly, we decided to replace the timing belt on the Celica. From what I've read, the Celica's engine, the potentially powerful 3SGTE, is not a interference engine, which means if the connection between the valvetrain of the engine and the crankshaft/pistons is broken, the pistons will not slam into the open valves. This is probably due to the relatively low compression of the turbo engine (~8:1 comp. ratio) or perhaps due to valve relief cuts in the top of the pistons (although most mass produced engines don't have these relief cuts). This means that if the timing belt snaps, the engine will not work, but it won't be internally damaged. However, we wanted to replace the belt since it might end our racing experience prematurely.

So onward we went to expose the timing belt hidden underneath a mass of piping, wiring, covers, and an alternator. In the process of this quest, we stripped the main crankshaft bolt (oops ... time to weld on a bigger bolt!), lost some assorted bolts, and found that the timing belt we had was for the wrong engine (thanks Napa.)

There was an unexpected surprise when we finally uncovered the timing belt. While it was in decent shape, we found out the intake camshaft was one tooth off. The mechanic who performed the headwork 60,000 miles ago must have accidentally timed the camshafts improperly. The car had symptoms of a hesitation at idle and high engine speeds, which could be explained by an intake camshaft off by a tooth.

We installed the correct belt, put the camshafts into the proper position and buttoned up the engine. We flipped the ignition, and the car seemed to run even worse! Hmm...

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