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| Initial timing for Mopar EI https://www.slantsix.org/forum/viewtopic.php?t=50208 |
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| Author: | jimbo921 [ Mon Oct 29, 2012 7:58 am ] |
| Post subject: | Initial timing for Mopar EI |
I recently upgraded my ignition on my 85 D100 to a mopar ECU setup ditching the Lean Burn system. Question is, what do you guys run for initial timing with this type setup? I started out at 12* but it seemed a little bit sluggish so I upped it to 15* My goal is drivability and miliage with this truck. |
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| Author: | SlantSixDan [ Mon Oct 29, 2012 8:05 am ] |
| Post subject: | |
What distributor did you use? You'll eventually want to get things dialled in such that you run about 5 to 7 degrees initial timing. |
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| Author: | jimbo921 [ Mon Oct 29, 2012 10:20 am ] |
| Post subject: | |
Its a stock replacement for a 76-87 (as listed by summit) AAZ-30-3690. The pickup inside is actually an OEM Mopar one, I replaced the one that was in there "remanufactured" as it was damaged and cheaply made. Set the gap to .008 |
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| Author: | SlantSixDan [ Mon Oct 29, 2012 10:35 am ] |
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Oof. With a "remanufactured" distributor it's a total guess at what kind of advance curves it'll produce. :shrug: |
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| Author: | Reed [ Mon Oct 29, 2012 10:39 am ] |
| Post subject: | |
Quote: Its a stock replacement for a 76-87 (as listed by summit) AAZ-30-3690
Well, there is problem #1. The distributors used in 76 vehicles were standard vacuum advance equipped electronic ignition distributors. By 87 all slant six distributors were dual pickup lean burn units with no mechanical or vacuum advance. While the units are physically interchangeable, they are not functionally interchangeable. The years between 76 and 87 saw the shift from standard electronic ignition to lean burn ignition and many different vacuum and mechanical advance curves built into the distributors depending on vehicle application and emissions packages. There is no one distributor that will work optimally (and in some cases at all) for every slant six equipped vehicle manufactured from 1976 to 1987.Problem #2- why the cutoff at 76? Slant sixes could be ordered with factory electronic ignition as far back as 1972. Was 1976 the arbitrary cutoff year picked by the Summit marketing department? You would be better served finding an old unmolested Chrysler distributor and either using it as is or rebuilding it. Since you have in vested in the Summit distributor, I highly recommend you spend the time to take it apart and see what governor is install and lubricate the springs and weights. Then I would take the time to carefully map out the mechanical advance curve and find out how much vacuum advance is given by the vacuum pod and at what vacuum the pod operates. |
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| Author: | DusterIdiot [ Mon Oct 29, 2012 6:08 pm ] |
| Post subject: | Uggghhh.... |
For $50+shipping (about $12 USPS), I could have sent you one and given you the curve information with it....Heck, I could take your vehicle's information and recurve one to fit your truck's needs...for the $50+shipping...  Cardone is a crap shoot...the only thing that isn't a guess is the vacc. advance can...it's a 20 degree at the crank vacc. advance most cruise vacc readings (20" to 14")...after that, springs and governor are your best guess without an autopsy. -D.Idiot |
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| Author: | jimbo921 [ Mon Oct 29, 2012 7:39 pm ] |
| Post subject: | |
Well the truck is running beautifully now so I don't need to go crazy messing with the timing curve springs etc.. I do that enough with the other toys. This ones supposed to be a daily driver parts runner. I have a decent adjustable light but no spare tach to map out the curve. I guess maybe the more correct question would be where should the timing be "all in" on an otherwise stock engine? I assume the can is 20, how much is the mechanical advance? Assuming this distributor is a somewhat stock curve for let's say a 76 without leanburn. Where should I set the initial timing at? Go with the 5 to 7? Is 15 too aggressive? The more timing I can throw at my big block the better but it's quite a different animal. |
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| Author: | DusterIdiot [ Mon Oct 29, 2012 7:53 pm ] |
| Post subject: | Timing... |
It's really a subjective topic... For most cars total timing of 47-52 is about right for a street/mileage build... Since trucks have to "haul" and are much heavier (power to weight ratio), your timing has to be more restrictive, and come on a bit slower to keep from pinging. So you may need to limit total timing to more like 43 degrees, and the curve may need to come on a lot slower...(i.e stocker springs). It's hard to say what you have until you take the pickup plate out of the distributor, that part number is the same for 1973-1975 dizzies, and 1976-1980 dizzies...so, if you got a 1974 governor it will advance 0-30 degrees as measured from the crank...if you got lucky and got a 1976 distributor then we could guess that it may limit mechanically at 22 degrees ("714" standard distributor)...maybe 18 degrees (Feather Duster, or 1977+ super six distributor governor), maybe you got lucky and got a 1977 slant six truck governor and it's a 26 degree limit. Until you autopsy the dizzy, or track the curve mechanically, we can throw darts at it all day...  -D.Idiot |
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| Author: | jimbo921 [ Tue Oct 30, 2012 4:22 am ] |
| Post subject: | |
Now it makes sense. I wish I asked the question when I already had the dizzy apart and laying on the bench though! No biggie I'll probably pop it out this weekend then. I still need to finish cleaning up my wiring a little and replace my valve cover gasket anyway. |
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| Author: | frank79912 [ Mon Dec 10, 2012 4:48 am ] |
| Post subject: | timimg |
I am running 6 degrees on a 83 d150- a833 manual 2.97 gear with a 74 A1 Cardone reman along with GM hei ignition.New timing chain, hottest NGK plugs I could find ( worn out oil burner that is rich) and only under extreme low speed load or hot high speed accel do I get a trace ping.Runs great otherwise.Condsidering...... |
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| Author: | olafla [ Mon Dec 10, 2012 8:54 am ] |
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Quote: Problem #2- why the cutoff at 76? Slant sixes could be ordered with factory electronic ignition as far back as 1972. Was 1976 the arbitrary cutoff year picked by the Summit marketing department?
This is a sidetrack from the topic of the thread, but it seem that most of the automotive aftermarket manufacturers and retailers believe that mother Mopar stopped turning out RWD cars after the A-body disappeared in 1976. The large-body Furys, Monacos, Cordobas and Chryslers seem to have dropped dead, and despite the performance of the 360 4-bbl Aspen/Volares, F/M/J-bodies are obviously just damaged goods not worth to mention. Gee, I wonder if Mike Jeffries know that... Olaf |
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| Author: | DusterIdiot [ Tue Dec 11, 2012 6:02 am ] |
| Post subject: | Uh no... |
Quote: This is a sidetrack from the topic of the thread, but it seem that most of the automotive aftermarket manufacturers and retailers believe that mother Mopar stopped turning out RWD cars after the A-body disappeared in 1976.
Not really, you can get al the typical speed parts for the late 360's or 318's, but the real fine point here is that 1975+ have smog controls of one kind or another and many jurisdictions in the US will not allow aftermarket mods of these cars if they are to be driven on a public road, The large-body Furys, Monacos, Cordobas and Chryslers seem to have dropped dead, and despite the performance of the 360 4-bbl Aspen/Volares, F/M/J-bodies are obviously just damaged goods not worth to mention. so the aftermarket manufacturer has to list them only for cars that don't have to pass an emissions test in the major metro area....so you have to look for parts for a 1976 Duster under 1974 Duster, etc...that being said the late mopar cars were also built for comfort and not looks so much as the muscle era died after 1974, so they aren't popular with a majority of the nostalgia crowd (making them cheaper and easier to pick up a wheezy 1978 Dodge Magnum for instance)... -D.Idiot |
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| Author: | olafla [ Tue Dec 11, 2012 2:32 pm ] |
| Post subject: | |
Thank you very much for that info, D.Idiot. That was a reason that I was totally unaware of, but it explains a lot! Olaf |
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