scottpeterd

Well, just finished my project to fix my vacuum advance. I am truly surprised what a difference it makes.

Last fall, before driving 3200 across the US, I knew my advance was leaking. But no time to replace it, as I was installing the drivetrain up to the day I had to leave. I had pulled the engine to regasket, install a new clutch, and rebush the shift linkage.

In my haste, I timed the engine to the standard 10 btc after install, plugged the vacuum line, and took off. Of course the engine wasn’t running properly, but it was better than it had been, as I had been unaware of the leak for some time.

One of the biggest symptoms was that the car was really rough idling and running when cold. This hit me in the Rockies, as it was close to freezing in the mornings.

This week, I finally got the advance installed, and retimed the engine. Yesterday took it out for the first time. It was about 36 F in the morning.

The difference was amazing. Engine fired up instantly, and idled smoothly. Unlike the usual 5 minute warmup before it could be driven, I could pull away after a minute. The engine had tons of bottom end torque, and pulled much more smoothly.

I had to close down the idle air screw, as it had been opened to maintain idle speed at the shop. So in addition to running with inadequate advance, the car was running lean.

Lesson learned. This simple little piece really has the capability to have major performance impact on the engine. I will now test it as part of my annual tuneup.