Bill, Could you provide us with a little more detail on your modification? I would definitely like to try that here. Especially as my 1981 car is exempt from Massachusetts emissions inspection. Thanks, Steelwings, 1559 ----- Original Message ----- From: content22207 To: dmcnews@xxxxxxxxxxxxxxx Sent: Wednesday, August 22, 2007 1:41 AM Subject: [DML] Clarification: DeLorean Spark Advance Before I get flamed out of existence, let me clarify DeLorean spark advance relative to its Volvo counterpart: The DeLorean ignition distributor has one centrifugal counterweight disabled. Otherwise it appears to be identical to Volvo F Series (mechanical advance spec's are one half Volvo's). To compensate, DeLo runs full manifold vacuum to the spark advance diaphragm. Of course this makes the engine extremely difficult to start and risks predetonation when the throttle plates are closed (max vacuum), so they stick a microswitch under the throttle plate linkage to operate a solenoid that cuts off vacuum spark advance when the plates are closed. And of course base ignition time is advanced 3 degrees before Volvo. In contrast, Volvo runs ported vacuum (same port as the purge signal to the charcoal canister) to the spark advance diaphragm. No microswitch or solenoid. Not only is this a much cleaner and simpler installation, but by virtue of having both counterweights active it actually yields more spark advance at higher RPM's (minimum vacuum), which is when you need it most. The whole DeLorean setup appears designed to maximize fuel burn at low RPM's, such as stuck in California traffic, not yield better performance. As I understand it the DeLorean distributor does have its missing counterwight inside -- it just isn't connected to the rotor hub. If the missing spring were replaced it should perform like a Volvo distributor (DeLo mechanical spec's are one half Volvo's). In such a state vacuum advance could then be attached directly to one of the throttle plate ports rather than the driver's intake rail. Otherwise, owners are stuck with DMC's rather convoluted setup. FWIW: I'm running a fully functional distributor and find performance to be quite invigorating. Bill Robertson #5939 [Non-text portions of this message have been removed] To address comments privately to the moderating team, please address: moderators@xxxxxxxxxxx For more info on the list, tech articles, cars for sale see www.dmcnews.com To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dmcnews/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/dmcnews/join (Yahoo! ID required) <*> To change settings via email: mailto:dmcnews-digest@xxxxxxxxxxxxxxx mailto:dmcnews-fullfeatured@xxxxxxxxxxxxxxx <*> To unsubscribe from this group, send an email to: dmcnews-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/