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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Some issues on timing:<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><b>On the mechanical workings:</b> The old distributors (64) had a system that did, in fact, wear excessively (you were right, Ron) due to their design. How many people took the time to take their distributor apart and lube the wear points???? Ya, me neither! The newer distributors have a cam system that reduces the wear ALMOST to nothing. The weights actually ROCK on the reluctor arms and don’t slide - thereby ALMOST eliminating any wear. A very brilliant design! However, I have seen wear on the weights and reluctor arms. Considering the thousands and thousands of times they have “rocked” against one another, it’s not surprising there is some wear after some 40 or 50+ years. I still lube them when overhauling a distributor. The cams design has nothing to do with the “timing curve” of the distributor - only the mechanical longevity of the system. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><b>The vacuum issue: </b>When an engine is idling or being used under low power (i.e. high vacuum), it LOVES more advance. One way to see this is to change the vacuum hose from the tuned port (above the throttle plates) and hook it up to the manifold (full vacuum) below the plates. You’ll then see an immediate increase in RPM! This is because the engine is running more EFFICENTLY. You haven’t changed the throttle position at all, and it runs faster. You’ll have to turn the idle screw down to get back to your original idle speed. I have a graph that shows the advance changes of an engine. The ONLY REAL difference in having the vacuum diaphragm hooked up to either the tuned port or the full vacuum port is at IDLE. My personal choice is the full manifold port. Vacuum advance provides a far better “drivability” on streets. My dad’s ‘51 Ford had vacuum advance and that was long before anyone heard of emissions. Ford (and other manufactures) spent a lot of money on the design of their vacuum systems. I realize the Volvo didn’t have one for whatever reason, but the Alpine 4 Cyl. did - go figure. The 289 HI PO engine didn’t come with a vacuum advance, because it was designed for racing where there is little time “cruising around on streets.” That is not to say that a vacuum distributor wouldn’t work for racing. I have no doubt Ford saved money by not having a vacuum distributor. They did, however, make a dual point distributor. The only purpose of dual points is to give the coil more time to build up its voltage (rise time) at high RPM. Electronic triggers don’t have that problem.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><b>Speaking of ignition:</b> I just came back from SEMA. Two companies I enjoy talking with each time I go are Pertronics and MSD. With regard to voltage, the Pertronics rep said all their units - the I, II, and III - can handle 12 volts to the module. The only time there was an issue was with a 4 cyl engine. For some reason (he said he wasn’t an engineer and couldn’t explain it), they had to have a resistor after the module and before the coil. Their Ignitor III looks interesting, as it has multi spark and a revlimiter. I haven’t had any personal experience with it.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><b>Concerning spark plugs:</b> MSD really likes Iridium plugs! I haven’t had any experience with them; but, if I wanted to change to different plugs, I would certainly look into them and would ask what heat range to use. Another thing they said was that they are backing down on having the larger gap sizes on plugs (.045+) because at higher engine speeds it’s harder to jump the gap (6AL). Thus, it’s better to go back to the lower gaps like in the .032 area.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Well, so much for my ramblings!<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Jerry Christopherson<o:p></o:p></p><p class=MsoNormal>9473187<o:p></o:p></p><p class=MsoNormal>TAC Insp #58<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Jerry Christopherson<o:p></o:p></p></div></body></html>