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MSD Electronic Distributor 8504 #1610079 04/20/14 11:38 PM 04/20/14 11:38 PM
Joined: Aug 2007 Posts: 2,356 Kentucky D dfsmopars OP top fuel
dfsmopars OP top fuel D Joined: Aug 2007 Posts: 2,356 Kentucky	Who is an expert on the MSD E-Curve distributor? If you have a good understanding of mechanical distributors (which I don't) it helps probably. I have an 8504 on my 5.9 Magnum and the options are too numerous. It would be nice to have them whittled down to a few. Who knows where this engine timing base should be using the dials in the dist and perhaps I can tweak from there. A dyno would be nice but that is not an option at the moment. Specs: Street (Spirited driving) .04" over flat top pistons Hughes .544 lift, 218�/228� roller cam (degreed) Roller rockers Iron X heads 9.5:1 compression 625 cfm carb SB Hooker headers 2.5" exhaust AT w/OD 3.55:1 gears 28.5" tires 4000+ lb b-body ‘72 Charger, 5.9 Magnum, Tremec 5 spd., Pro-Touring ‘14 Big Horn, Quad Cab, 4x4, 1500

Re: MSD Electronic Distributor 8504 [Re: dfsmopars] #1610080 04/21/14 12:23 AM 04/21/14 12:23 AM
Joined: Apr 2005 Posts: 12,271 Overpriced Housing Central RobX4406 I Live Here
RobX4406 I Live Here Joined: Apr 2005 Posts: 12,271 Overpriced Housing Central	It's pretty simple really. Using vacuum advance? Pick which one from the graph. See number on the vertical side of dial settings chart. If not using vac adv, just use the #1 line. Find the curve you want in the charts, I'd think 15 or 20, all in at 2500, 20 is G and 15* is K. Go across the top and find those letters. Set dials to the setting it shows, G = 0,7 K = 1,1. Initial should be anywhere from 14-20 depending on how much total the engine will handle and ease of starting when hot. You may have to compromise the total or initial timing number to get a happy spot that the 5* split in curves will provide. You need to find what the engine likes for initial and total timing. Then it's finding the curve that fits best. Either of the two suggested should get you in the ballpark to start.

Re: MSD Electronic Distributor 8504 [Re: dfsmopars] #1610081 04/21/14 12:49 AM 04/21/14 12:49 AM
Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska	Set initial with the vac gauge method. then set the total (checked with vac adv capped) to 35 (initial + mech), Then mix/match springs staying just under the pinging point up thru the gears on your hottest/driest day with the adv starting no less than 200 RPM above your hot in gear idle speed which is what the eng will see from stoplight to stoplight. Then plug in/adj the vac adv. CCW with a 3/32" allen wrench gives less adv at a given in hg vac amount & stay just under the pinging point in everyday driving under varying vac levels (load) on your hottest/driest day. #1 is do em IN ORDER live every 24 hour block of time like it's your last day on earth

Re: MSD Electronic Distributor 8504 [Re: RobX4406] #1610082 04/21/14 12:58 AM 04/21/14 12:58 AM
Joined: Aug 2007 Posts: 2,356 Kentucky D dfsmopars OP top fuel
dfsmopars OP top fuel D Joined: Aug 2007 Posts: 2,356 Kentucky	I am running vacuum because it being a street car and fuel economy is somewhat important on the Hot Rod Power Tour and such. Do I choose the vacuum advance curve or does the engine itself dictate that? If I choose curve 3 vacuum then that will limit the vacuum advance to 10�? What you are saying about the graph (which I have studied many times) makes good sense but curious why you say all in at 2500 rpm? Are you just getting me in the ballpark with that or is it just best to advance the timing really quick in this case? The cam comes in around 1800 to 2000 rpm. The stall is slightly more than that at around 2500. Based on your reply 4,7 or 5,1 would be a good start? That is 10� vacuum advance, with either 15� or 20� electronic advance. I know that once I grasp the concept of this thing like you have I will be able to utilize its benefits. ‘72 Charger, 5.9 Magnum, Tremec 5 spd., Pro-Touring ‘14 Big Horn, Quad Cab, 4x4, 1500

Re: MSD Electronic Distributor 8504 [Re: dfsmopars] #1610083 04/21/14 01:26 AM 04/21/14 01:26 AM
Joined: Apr 2005 Posts: 12,271 Overpriced Housing Central RobX4406 I Live Here
RobX4406 I Live Here Joined: Apr 2005 Posts: 12,271 Overpriced Housing Central	Quote: I am running vacuum because it being a street car and fuel economy is somewhat important on the Hot Rod Power Tour and such. Do I choose the vacuum advance curve or does the engine itself dictate that? If I choose curve 3 vacuum then that will limit the vacuum advance to 10�? What you are saying about the graph (which I have studied many times) makes good sense but curious why you say all in at 2500 rpm? Are you just getting me in the ballpark with that or is it just best to advance the timing really quick in this case? The cam comes in around 1800 to 2000 rpm. The stall is slightly more than that at around 2500. Based on your reply 4,7 or 5,1 would be a good start? That is 10� vacuum advance, with either 15� or 20� electronic advance. I know that once I grasp the concept of this thing like you have I will be able to utilize its benefits. Pretty much spot on. On the right track. Why do you want the vacuum adv all dumped in so quick. I'd use vac setting 1 to slope it in more gradually and dump it out gradually when vacuum drops.

Re: MSD Electronic Distributor 8504 [Re: dfsmopars] #1610084 04/21/14 04:58 AM 04/21/14 04:58 AM
Joined: Jan 2003 Posts: 27,471 So Cal autoxcuda Too Many Posts
autoxcuda Too Many Posts Joined: Jan 2003 Posts: 27,471 So Cal	Quote: Who is an expert on the MSD E-Curve distributor? If you have a good understanding of mechanical distributors (which I don't) it helps probably. I have an 8504 on my 5.9 Magnum and the options are too numerous. It would be nice to have them whittled down to a few. Who knows where this engine timing base should be using the dials in the dist and perhaps I can tweak from there. A dyno would be nice but that is not an option at the moment. Specs: Street (Spirited driving) .04" over flat top pistons Hughes .544 lift, 218�/228� roller cam (degreed) Roller rockers Iron X heads 9.5:1 compression 625 cfm carb SB Hooker headers 2.5" exhaust AT w/OD 3.55:1 gears 28.5" tires 4000+ lb b-body I don't know if they have corrected it. But my E-curve would not work with the MSD solid state coil. Traditional oil filled coil, worked fine. Frustrating to figure out. Last edited by autoxcuda; 04/21/14 05:10 AM.

Re: MSD Electronic Distributor 8504 [Re: RobX4406] #1610085 04/24/14 11:42 PM 04/24/14 11:42 PM
Joined: Aug 2007 Posts: 2,356 Kentucky D dfsmopars OP top fuel
dfsmopars OP top fuel D Joined: Aug 2007 Posts: 2,356 Kentucky	Robx, got it about where I think it wants to be. Started with 15* electronic plus 10* vacuum at 37* total timing. It ran good with the quick curve you recommended. Bumped it down to 10* advanced and set the total at 42* and it perhaps performed a little better on the top end but it certainly did not hurt it. So with the vacuum and electronic advance the initial is at 22*. Starts quick, no detonation and the dead spot at initial WOT is gone. Understanding this thing a little better. Thanks for the direction. ‘72 Charger, 5.9 Magnum, Tremec 5 spd., Pro-Touring ‘14 Big Horn, Quad Cab, 4x4, 1500

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