I am corresponding with an owner Re: spark advance. As we all know, DMC decided to use only one centrifugal counterweight inside its distributors rather than two (Volvo used two on its imports to the exact same North American market). To compensate, DMC: - Bumped base ignition time from 10 to 13 degrees BTDC - Ran full manifold vacuum rather than ported vacuum to the advance diaphragm This oOf course leads to generally overadvanced ignition, so for better starting and cold engine performance DMC further: - Ran its vacuum through a thermactor valve and an idle cutoff solenoid before the distributor My question: Why did DMC find it necessary to reinvent the spark advance wheel? B28F has two centrifugal counterweights, 10 degree base ignition time (steeper advance curve), and only one vacuum line from a ported barb under the throttle plates directly to the advance diaphragm. What could be simpler? And again: Volvo imported its setup into the exact same North American markets, during the exact same time period (1981-1983). If their setup was good enough for the US government, shouldn't DMC have been able to use it too? BTW: US Volvos also came with a Y pipe and single catalytic converter. They used Lambda as well. More engineering from Dunmurry that causes me to scratch my head. Bill Robertson #5939 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/