New distributor install

[Ttrammell_58]

Removed engine from 911T, sent out for rebuild. Removed junk Marelli distributor. Rotor position not recorded. Obtained 123 dizzy as replacement. New Permatune CDI and coil. New wires and plugs gapped .045 per Permatune. Engine set at TDC #1 compression.
Dizzy installed per instructions, no start.
Question: must rotor be installed in one specific location, i.e. must distributor gear be engaged in only one exact spot? If so , is there a method to find correct location?

[Tom]

No experience with that particular engine, but in general when installing an old-school distributor like that, you need to set the motor to TDC #1 on the compression stroke, and then point the rotor toward the #1 spark plug wire on the distributor cap.

[dr bob]

Quick questions, follow-ons to Tom's TDC #1 compression guidance --

-- Do you get any spark at all? There are some handy tools that fit in the wire, but it's usually easier to just pull a plug wire, attach to a spare/old/anything plug. Hold or rest that plug against an engine ground, and crank the engine. Verify spark/no spark.

-- If you see a spark, there's a reasonable chance the engine was at TDC #1 on the exhaust stroke. In my experience, there's a 50% chance of getting it right the first time, and close to 100% chance of getting it wrong. Easy to solve by removing the distributor, rotating the crankshaft 1 full revolution, then installing the distributor again with rotor pointing to #1 cylinder. Follow the Permatune instructions for setting initial timing. From foggy memory, you can do that by turning the distributor and watching for spark at #1 wire.

-- If you didn't see any spark at all from that first test, go back through your wiring and connections. Look hard at ground connections.

***** Use extreme caution while tinkering and testing with CDI ignition. They pack a really nasty jolt if you happen to be the ground path for a spark. I'm pretty sure I suffered signafekant brayn demege early in my tinkering adventures. There's a very reasonable chance the jolt will kill you if it passes through you the wrong way. Don't Risk It.

Stranded thought -- Wire leads dressing is critical with electronic ignition boxes. One critical detail is that they really struggle with basic metal-conductor "performance" ignition wires. It took me a bit of head scratching to figure out that resistor-type plug wires were needed for my engine to actually run with a CDI upgrade.