Sunday, July 12, 2009

Timing and carb adjustments

The car starts and runs great then its cold. But once the choke gets down to the last 2 notches, the engine won't idle and slowly dies.

I have a 009 distributor (0231178009) with a Pertronix electronic ignition, and I've read that since its a mechanical advance only, that its best to set the timing to 28 - 32 degrees BTDC (going to the right of TDC). I don't have degree markings on my crank shaft pulley so I had to figure out how far 28 - 32 degrees would be. Here is how I figured that out.

Pulley dia. is 7"
pi = 3.1428

7 * 3.1428 = 22" (21.9996")
22" / 360 = .0611" for each degree
.0611 * 30 degrees = 1.8333"

So to find 28 - 32 degrees BTDC, I messure 1.8333" to the right of my TDC, and placed a mark on the pulley.
( I used white finger nail paint, thanks honey! )

I also have read that the 009's are not all calibrated the same, so the max advance on each might very. The best way to get it set is to use a timing light, and rev the engine up until the 30 degree make stops moving. Then rotate the distributor until the mark is lined up to the seam of the engine case. Tighten the distributor screw so that it doesn't move.

Next I need to adjust the carb. I followed the directions on a couple of web sites. I won't describe the entire process, you can check that out at these links.
Rob and Dave's aircooled volkswagen page or VW Tech page (has a picture)

The end result, a nice smooth running engine ... nope! Still runs the same way. Starts and runs fine when its cool, but as soon as the choke gets to the last 2 notches, when left to idle, it dies. When the engine is warmed up, it still starts fine, just won't idle.

Back to the drawing board.

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