I've had ignition issues with my '73 Dart [360 engine with the MP electronic ignition] for quite some time now. Generally the engine is hard to start and misfires when cold. Once fully warmed up it smooths out for the most part. Last year the orange box went out, so I replaced it with an oem unit I had laying around. Later the engine started to run rough and stalled sometimes when idling. I replaced the box with a new one, also replaced the ballast resistor. The first start after that was great; it fired right up without any hesitation. A week later it was the same old story again; hard to start and running rough. The engine is mechanically sound, doesn't burn oil, plugs [NGK] are new and look clear. [Engine was rebuild about 15.000 miles ago] Plug wires [MSD 8.5mm] are new. Wires 5 & 7 are separated. I've added a ground strap from the ignition module to the engine block, another strap runs from the inner fender to the right cylinder head.I just replaced the reluctor and pick-up inside the distributor. I noticed the new reluctor didn't fit as tight as the original one. I had some play on the shaft. Not much, but just noticeable. I adjusted the air gap between reluctor and pick-up, however I did notice when the distributor shaft was rotated 180 degrees this gap gets at least twice as big. I assume the hole in the reluctor is out of center? I made the air gap adjustment on the tight spot so the reluctor doesn't hit the pick-up.Anyway, I started the engine with the new reluctor & pick-up...it runs like crap now. Shaking and surging, sounds odd out the exhaust. Idles at about 1100 rpm instead of the previous 900 or so. I did carefully mark the base of the distributor so I'm positive it went back in at the same position. Will a varying air gap cause ignition problems?This distributor was bought new when the engine was rebuild.Any help would be appriciated, thanks.
the reluctor should be even all the way around...is there any possability the upper distributer bushing or the lower distributer bushing is bad..please check the shaft by wiggling it...if it wiggles... figure out which way the rotor is pointing... pull the distributer... stick a big screw driver into the middle slot in the oil pump drive gear... rock it back and forth.. it SHOULD NOT ROCK at all.. or perhaps a TINY amount.. you will need a bright flashlight aiming down the hole when you do this..i have found the flanged bushing under the oil pump shaft to be worn out or away... allowing the intermediate shaft to rock.. when i worked at an engine builder back in the mid 90s.. i ran across some intermediate shafts that did not have a proper finish where the shaft passes through the bushings.. if the bushing gets eaten out.. the shaft will rock.. and wear the bushings out in the distributer.. could you have a bad reluctor.. YEP... could be made overseas where they don't always have a clue...find a different brand... or stop by a napa store..
Wayne is right on both accounts, I would install a new distributor. The bushing should have zero play. Second when you gap the reluctor you need to use a brass feeler gauge. Other wise you can damage the relutor by making it magnetic. This can also cause box failures. Finally shaft bushing should be checked and replaced if necessary. Good luck Doc..
My mistake...what I meant was I noticed there was a little play between the [new]reluctor and the shaft. I haven't checked the shaft & oil pump drive gear for play yet. I did put in the old reluctor but it ran just as bad. When I had the distributor out of the engine I noticed the varying gap between reluctor & pick-up. Next weekend I will pull the distributor again and have a look. It did started to run real bad right after the new reluctor & pick-up went in, so something electrical went wrong I would think.BTW, where do I get a brass feeler gauge, I've never seen those anywhere.If you ask me this should be included when you buy a reluctor or pick-up...like when you buy a bookcase at Ikea, an allen wrench is included...Anyway, I let you know what I find out, thanks so far.
OEM/18 blades combination Tune-Up gauge with 6 wire gauges and 1 electrode adjusting toolPrice: $6.99Part Number: 25023 Alternate Part Number: 2206 brass blades sizes 0.006 In. (152 mm) to 0.016 In. (406 mm)12 steels blades sizes 0.010 In. (254 mm) to 0.026 In. (660 mm)6 wire gauges sizes 0.025 In. (635 mm) to 0.045 (1.143 mm)1 electrode adjusting toolsome of the other feeler gauges have one brass shim blade in the pack...by the way.. do you have a digital volt meter???set the digital multimeter to 2K ohm scale... 2,000 ohms..OHM the pick up coil... 500 to 1500 is expected.. but usually around 980 ohms is what you will get... now.. before disconnecting... change the meter setting to 2 volts AC... spin the shaft..you should get just over 1.0 volts AC... if you don't then the ignition module will not fire...with the distributer in.. hopefully you will get as close to 1.0 volts AC as possible..
Ok, today I removed the distributor again. I did the 'screwdriver test' to check for play in the oil pump drive bushing. I tried a few times but I don't see or feel any play there. There is some tiny play between the oil pump drive gear & cam gear [when rotating the screwdriver clockwise and counterclockwise] but it did not move sideways. Then the distributor...there is no side-play on the lower part of the shaft. The shaft on top has a tiny amount of play, but only if I really get a hard grip on it.The reluctor seems to be even all the way around, yet there is a varying air gap between reluctor and pick-up. I did notice the shaft [where the reluctor sits] is able to move up & down about 1.5 mm. [sorry, not used to inches...]I'm not sure if that's normal or not. Thanks again.
any chance of having an old distributer cap????? you could cut the top out.. so you leave the 8 terminals for the wires... with the open cap installed.. you can now.. with the rotor on.. see if the gap from the tip of the rotor is the same all the way around... you may have to wrap the housing with layers of masking tape to get the cap to fit snug and centered... some caps are molded from patterns taken from caps... instead of a direct machining process.. some fit too tight.. some fit too loose.. need to find the brand that is just right.. tape is just for the test.. now you can measure it as you rotate it.. or just laying the distributer on its side on the work bench.. spinning the shaft... seeing if the shaft is bent??? causing the reluctor to wobble.. create some kind of block to fit under the end of the shaft.. to check the distance...you could also.. if you have a big chucked power drill.. attach to the bottom of the distributer shaft... SPIN... does the shaft run true???? you could also use a piece of hose on the shaft... with a clamp reducing the side of the hose to the largest drill bit that will fit in the chuck...~~~~~~~~~~~~~~~~~~~~~~~~~~~up and down motion in the upper section of the distributer is expected.. if you pull the reluctor.. the vacuum advance... the breaker plate... the felt washer from the end of the distributer shaft.. you can with some long thin nose pliers.. grasp the wire retainer and extract it.. this allows you to separate the upper shaft above the advance weights.. there is an article on recurving and modifications in the HOW TO or the TECH section...you just might want to find another reluctor first... drop it on... it could have been smashed.. distorting it...
check this article.... http://www.moparmusclemagazine.com/techarticles/engine/mopp_0301_mopar_electronic_ignition_system/viewall.htmlperhaps this will help...
Thanks for the fast response...No, I don't have an old cap...Interesting article.You got some good ideas, I may pull the distributor again to check that shaft.I did notice the air gap between reluctor & pick-up varied, no matter if I used the original reluctor or the new reluctor.i'll let you know if I find something else.
What are we talking about here? a 40+ yr. old distributor. The reluctor can vary due to a worn bushing in the distributor. Chances are you will need to replace the distributor with a new one to solve your issue. Good Luck
It's about 10 years old...but in either case you're probably right. I might as well just get a new distributor.
I finally got my distributor [see my other post 'Mopar distributor'], but this thing is worse than what I got. I put in on the engine but it runs just as bad...I have just send this distributor back to Summit because it has play on the shaft, a loose pick-up plate and an uneven air gap as well. While I was working on the engine I put a socket on the crank pulley bolt and turned the engine over to watch the rotor. It seems to have play on the chain since the rotor doesn't turn right away; I could turn the wrench on the crank bolt about an inch or so in both directions before the rotor moved. I'm still not sure I found my culprit, this engine was just idling beautiful less than 1000 miles ago. Timing chains/gears don't wear overnight, do they? I was gonna say a [slightly] worn timing chain doesn't cause hard starting and misfiring but maybe it will. But the worn chain doesn't explain the bad running/misfiring right after the reluctor and pick-up was changed so something electrical is going on as well I would think.I'm pissed off and relieved at the same time. Pissed off because this is a rebuild engine with only about 15.000 miles on it, relieved because I found a weak spot. Were to go from here, should I replace the timing chain/gear first and see what happens?
a few more things.. pull your distributer.. with a flashlight... and a big flat screw driver thats long enough to reach into the engine thru the distributer opening.. stick the screwdriver into the slot in the distributer drive/intermediate shaft... while watching.. turn the screwdriver back and forth.. you should NOT get side to side or front and back motion from the gear.. if you do.. then there is a flanged bushing under the intermediate shaft that needs to be replaced..back in the early and mid 90s.. one brand of new intermediate shafts were exposed to water and reclaimed by shot blasting.. this ruined the polished section where the bushing rides.. this causes the tool steel shaft to eat away the bronze bushing.. allowing the gear to drag the bottom of the distributer shaft around in directions it was never designed to .. this wears out the distributer shaft bushings .. change your timing chain set...you may want to drop your pan if you can get room .. so you can clean out any broken plastic gear teeth... what???say.. i worked on a dodge van last night.. no start... spark from the coil but not from the individual spark plug wires.. and this thing was misfiring before it failed to start...wow.... this is what i found..reluctor... notice the keyways are NOT both equal... if you have the reluctor on the wrong way... the rotor tip will be away from the cap terminals when the spark is generated... causing you a misfire..B and RB engines have a distributer rotation in one direction.. LA motors have a distributer going the other way... look at the arrows on the top of the reluctor.. if the shaft turns left.. position the reluctor with the pin on that side... right.. use the other.. follow the arrows..pickup coils are easily replaced.. 20 minutes on a good day...
Thanks...I already did the screwdriver test; there is no visible play on the shaft below the distributor. What is that part you are holding in your hand, it's a bit of a foggy picture...Looks like a ballast resistor. I already changed mine last year. Can I [temporary] bypass the ballast resistor?What brand timing set do you recommend?
the fuzzy picture is a mopar ignition rotor.. that the burned area went thru and stole the spark preventing the engine from starting.. bypassing the ballast resistor... probably not a great idea.. the newest modules don't use all 5 pins.... the electronics have been upgraded... some people have bypassed the resistor and changed the coil by using the chrysler electronic distributer with a 4 pin GM HEI module... on a heat sink... all you have to do is get the polarity correct from the pickup coil... so the rotor is pointing toward a cap terminal when the spark is discharged... not between the cap terminals. the pickup coil and reluctor are just a signal generator... to cause the module electronics to open and close the connection to ground for the coil... i wonder if there is excessive play in the brand new distributer... if a piece of manufacturing tooling broke and they just grabbed a replacement and shoved it in.. or if the incorrect bushing was sourced..as for what brand....cloyes is usually a great brand.. but the usual quality of other brands seems to be decent.