The singe point breaker plate rests on three bronze pads, and is held down with a spring steel clip. It's not the most accurate system, and does not swing through a perfect central arc, thus the dwell change. Chrysler was aware of this and gives an acceptable dwell variation in the shop manuals. The dual point plate pivots on a ball bearing, on center with the shaft. 300ly, Don ----- Original Message ----- From: Marshall Larson <yelof@xxxx> To: <chrysler300@xxxxxxxxxxxxxxx> Sent: Tuesday, December 17, 2002 9:51 AM Subject: Re: [Chrysler300] Distributor rebuild - where? > If the dwell changes when the vacuum advance moves the breaker plate, the > plate must be mounted excenteric to the shaft. Are you saying that is > the case? If it is, I didn't know that. > > Marshall. > > On Mon, 16 Dec 2002 19:45:06 -0800 "Don Verity" <d.verity@xxxx> > writes: > > Dwell is the time in degrees that the coil is building up energy to > > fire the > > spark plugs. More is better, to an extent. To much will leave you > > with a > > small point gap and they will burn rapidly, to little and you will > > not get > > enough coil saturation time and will wear the rubbing block on the > > points > > faster. The reason for duals is to get more dwell without the bad > > effects of > > a small point gap. Just before the first set closes, the second > > starts to > > open, so you get the combined dwell of both sets. Each runs at 28-32 > > degrees. With both running you get almost 40. I usually change the > > points in > > my G every couple of years. Back in the "old days" when all cars had > > points > > and were daily drivers, tune-ups were a twice a year thing. Changing > > your > > point gap will change the timing, as will point wear.Worn bushings > > on an > > electronic distributor won't effect dwell. If it's bad enough > > though, the > > reluctor will contact the pick up coil with bad results! Worn > > bushings in a > > point set up will definitely effect dwell because the shaft is > > moving around > > changing the point gap. On most single point systems, the vacuum > > advance > > will change the dwell also. Sometimes by 4-5 degrees. The dual > > systems > > breaker plate rides on a bearing and is much more accurate, usually > > within a > > degree. > > 300ly, > > Don > > ----- Original Message ----- > > From: Owen & Jo Grigg <ram300@xxxx> > > To: <chrysler300@xxxxxxxxxxxxxxx>; John Hertog > > <crossram@xxxx> > > Sent: Monday, December 16, 2002 1:15 PM > > Subject: Re: [Chrysler300] Distributor rebuild - where? > > > > > > > Hi John & all > > > > > > I am running a Pertronix unit on my 300C, doesn't seem to be any > > noticeable > > > difference in idle or performance. Haven't checked the dwell, just > > installed > > > the Pertronix and put a timing light on the crank. I thought the > > main > > > reason for correct dwell angle was to take the heat away from the > > > points....stop them burning out? Does it also effect ignition > > timing? Can > > > you compensate by turning, advancing/retarding the distributor? > > Could it > > > just be flogged distributor bushes causing problems on some cars > > with > > > Pertronix systems? > > > As you can see I'm a bit of a novice when it comes to > > distributors.....so > > go > > > easy on me ok. > > > What are the symptons I should be looking for??Don't much like > > changing > > > points, but if it makes more power....... > > > > > > Owen > > > > > > > > > ----- Original Message ----- > > > From: John Hertog <crossram@xxxx> > > > To: John L. Chesnutt <chesnutt@xxxx>; > > <chrysler300@xxxxxxxxxxxxxxx>; > > > Vath, Michael J. <mjvath@xxxx> > > > Sent: Tuesday, December 17, 2002 6:56 AM > > > Subject: [Chrysler300] Distributor rebuild - where? > > > > > > > > > > Hi Mike, > > > > > > > > The actual bushing is available from NAPA . I don't recommend > > the > > > > Pertronix - dwell is unacceptable, and cars I installed > > Pertronix on had > > > to > > > > be reconverted to points. As far as rebuilder, you might want to > > contact > > > Don > > > > Verity - d.verity@xxxx ; he has a Sun distributor machine, > > and can > > set > > > up > > > > the distributor properly as per spec once he has rebuilt it. > > Don's > > rebuilt > > > a > > > > few for me. > > > > > > > > John > > > > > > > > > > > > > > > > To send a message to this group, send an email to: > > > > Chrysler300@xxxxxxxxxxxxxxx > > > > > > > > For list server instructions, go to > > > http://www.chrysler300club.com/yahoolist/inst.htm > > > > > > > > To unsubscribe from this group, send an email to: > > > > Chrysler300-unsubscribe@xxxxxxxxxxxxxxx > > > > > > > > > > > > > > > > Your use of Yahoo! Groups is subject to > > http://docs.yahoo.com/info/terms/ > > > > > > > > > > > > > > > > > > > > > To send a message to this group, send an email to: > > > Chrysler300@xxxxxxxxxxxxxxx > > > > > > For list server instructions, go to > > http://www.chrysler300club.com/yahoolist/inst.htm > > > > > > To unsubscribe from this group, send an email to: > > > Chrysler300-unsubscribe@xxxxxxxxxxxxxxx > > > > > > > > > > > > Your use of Yahoo! Groups is subject to > > http://docs.yahoo.com/info/terms/ > > > > > > > > > > > > To send a message to this group, send an email to: > > Chrysler300@xxxxxxxxxxxxxxx > > > > For list server instructions, go to > > http://www.chrysler300club.com/yahoolist/inst.htm > > > > To unsubscribe from this group, send an email to: > > Chrysler300-unsubscribe@xxxxxxxxxxxxxxx > > > > > > > > Your use of Yahoo! Groups is subject to > > http://docs.yahoo.com/info/terms/ > > > > > > > > > ________________________________________________________________ > Sign Up for Juno Platinum Internet Access Today > Only $9.95 per month! > Visit www.juno.com > > To send a message to this group, send an email to: > Chrysler300@xxxxxxxxxxxxxxx > > For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm > > To unsubscribe from this group, send an email to: > Chrysler300-unsubscribe@xxxxxxxxxxxxxxx > > > > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ > >