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Hello- > When I recently checked my timing, for some reason I clipped the pickup onto > the other leads as well and discovered that no.3 read 5 deg adv as opposed > to the 7.5 deg of no.1! I had heard that this was a rumoured feature of our > engines as it would make no.3 run cooler. Well, kinda... running more retarded than what is needed actually makes you run hotter. Distributors fitted to engines with oil coolers whose exhaust air was directed to cylinders 3 and 4 retarded timing on #3 by 4 crank degrees (usually written in spec books as 2 distributor degrees). This was because #3 ran hot, and therefore needed less advance to start with, and it was more prone to detonating. This was to "even the playing field," so to speak. > Thing is, I'm using a Pertronix > contactless ignition module! So what could this mean? Is it possible that > the pertronix magnet ring has a diplaced magnet for no.3 (there is no > orientation marking so it would be pure chance that it ended up in the right > place!) Nah. > or could it be that there is a mistake in my magnet ring which again > by chance I fitted in the right place? Likely. > Or perhaps the Pertronics relies on > the lobes of the dist cam to control the magnet flux so the timing is still > controlled by the cam? No. > Anyone know? The Pertronix relies on its own magnets. However, the Pertronix places four magnets in a circle with a very small radius. Result? A slight inaccuracy translates to a massive timing difference. What you are seeing is common with Pertronix modules - they aren't very accurate. I prefer Compufire - the discs have magnets placed in a circle with a much larger radius and they seem to be more accurate (from the ones I've gotten). When used in a blueprinted distributor with all slop carefully taken out of it (i.e. better than new), the timing is pretty danged nice. That runs a close, close second to a Mallory distributor, but still quite a distance behind a crank-triggered setup. Take care, Shad Laws LN Engineering http://www.lnengineering.com ------------------------------------------------------------------- List info at http://www.vwtype3.org/list | mailto:gregm@vwtype3.org