I've got a few questions on setting the dwell on an E4ME and hopefully someone can set me straight. Is there an initial setting for the air bleed and the idle mix screws prior to setting dwell? I'm able to come up with infinate combinations of idle bleed and idle mixture screw combos that result in 25-35 degrees dwell. I've also noted that the dwell drifts between 25-35 degrees at idle; should I be concerned? The dwell meter needle bounces a bit, but that's expected. Thanks.

 

the needle will bounch some thats normal, Start with 3 turns out on the mixture screws then set the idle air bleed screw. I like to run the crew 4.5 turns out from full bottom. Thats where I found my Oldsmobiles liked to run the best. Odly enough my Camaro does too.

 

Kewl, thanks for the feedback. Sounds like I'm in the ballpark then, 3 1/2 on idle mix and around midway on the travel for the idle air bleed. I'm still curious about the wandering dwell, drifting from 25 up to 35 degrees. Should it be reason for concern?

 

When your setting the dwell do you have you meter in the 8 or 6cyl setting. Odd as it may seem the 6 cyl setting is the one you should be using if you are using the 8 it may be the reason it's waundering so much. Also makesure you have a good connection. I have to admit with the stock HO carb, my setting tended to wander alot more than with my Modified Olds carb. I wouldn't bee to concerned about it as long as it's not throwing any codes and there is no drivability issue with the vehicle. Also keep in mind that the stting is sensitive to load if you own a automatic car try putting it in drive and setting the dwell there. your dwell will vary if thing such as your cooling fans kick on or you A/C clutch is turning on or off. Things as small as your radio playing while setting the dwell will place a tiny but noticable oad on the altenature therefore causing your dwell to change. Just an FYI. Best of luck.

 

I use very slightly different starting points with equal success. I use what I call the "rule of 4." 4 turns out on the mixture screws, 4 turns out on the IAB. (Inside the carb I also put the lean stop out 4 turns as a starting point and then adjust the rich stop to whatever achieves the spec'ed 1/8" total travel of the M/C hanger).

 

Never thought of doing it that way. Before I had a dwell meter I used to adjust it by turning the mixture screws out 3 turns with the air bleed in all the way, then I would turn the airbleed out 1 turn every 10 seconds until I got to 4.5 turns. If the motor stumbled or the idle quality suffred I would turn the mixture screws out 1/2 turn and continue until I got to my goal or the motor's Idle quality suffered again. Only issue I ever had with that method is there was a 50/50 chance of passing NJ pollution tests.

 

Thanks for all the feedback guys. I did use the six cylinder setting. From the sound of things, I've got it set properly.

What is odd is that there are infinite combinations of idle mix and idle air bleed screw settings that will result in good idle AND the desired dwell angle. Guess maybe I'm overly curious is all . As for the dwell floating between 25 and 35 degrees, it is random in nature, taking maybe 3-10 seconds to move +/- 5 degrees. And yes, any load whatsoever definately does impact the dwell; IMO that's normal for things.

Thanks again guys

Bill

 

What's the importance of the 1/8" total travel ? I haven't measured it but my carb's not giving me any problems, either.