Vacuum Advance
Thread Starter
Instructor
Joined: Jan 2007
Posts: 233
Likes: 41
From: Simpsonville SC
Vacuum Advance
I have made good progress dialing in my timing on my 78 L-82. I followed Lars recommendations on setting total mechanical advance and the engine responded well to this. The only thing I still notice is I have a little 'chug' during off idle driving. I suspect I am getting too much vacuum advance. I don’t see any numbers on my advance pot to identify what I have but I get about 10deg. of advance when it’s active. I’m thinking of getting an adjustable vacuum advance pot. Does anyone have experience with these and do they work?
Thread Starter
Instructor
Joined: Jan 2007
Posts: 233
Likes: 41
From: Simpsonville SC
Well, disconnected the EGR, no difference still chugging at off idle. I disconnected the vacuum advance and the chug went away. So I assume I need to tweak the vac advance of just leave it disconnected. I can't tell what vacuum can I have installed because I see no numbers on it. I also don't know the specs of what was supposed to be on the car originally. Lars document on vacuum advance that lists all the different ones doesn't show the vacuum or advance deg. for a stock 78 L-82. Anyone know this information?
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Well, disconnected the EGR, no difference still chugging at off idle. I disconnected the vacuum advance and the chug went away. So I assume I need to tweak the vac advance of just leave it disconnected. I can't tell what vacuum can I have installed because I see no numbers on it. I also don't know the specs of what was supposed to be on the car originally. Lars document on vacuum advance that lists all the different ones doesn't show the vacuum or advance deg. for a stock 78 L-82. Anyone know this information?
Drifting
Joined: Dec 2002
Posts: 1,946
Likes: 28
From: Long Beach CA
Don't bother with the adjustable vacuum advance canisters. They're a pain to set up correctly for the right amount of advance and vacuum levels. The one I had only lasted about a year (not all that many miles) and the diaphragm inside broke.
