Distributor issues?

[Oystercopy]

Hey guys.

I've had a runnability problem with this car for about 4 years. Threw a whole lot of parts and money at it over the years. The engine has had a "stumble" for a long time. It runs very rough and even misfires/backfires a lot during acceleration. I've replaced (literally) everything on this engine (ignition-wise) except the distributor itself. Ignition coil is a new MSD, so are spark plug wires, plugs, rotor and cap. Ignition module was replaced also. The problem (seemed) to start when I had the new cam kit put in. I don't believe it was anything in the kit that caused the problem (itself) although we did have a weak valve spring that has since been replaced.

I understand that distributors can go bad, I've just never had reason to replace one, and I'm also not sure I need to get one that is specifically for this engine and even the cam? Do the shafts wear out, causing issues? My car has the upgraded electronic ignition so no points.

Any help appreciated!
OC

 

[Challenger RTA]

KISS. Keep It Simple Sam. Variations on the phrase include "keep it super simple", "keep it simple, silly", "keep it short and simple", "keep it short and sweet", "keep it simple and straightforward", "keep it small and simple", "keep it simple, soldier", "keep it simple, sailor", "keep it simple, sweetie", "keep it stupidly simple", or "keep it sweet and simple"

Been there done that!
Distributor related
Firing order correct, I check mine a number of times and thought it was correct. Low and behold the 10th time or what ever, two were switched. It happens!

1 You changed the distributor cap but is it good. Lets say it is. Spark jumping in cap.
2 Are the spark plugs good? I would aways suspect that. Small cracks can't always be seen.
3 Are the spark plug wires good? They can be check with a meter. that dose not always indicate there bad. A megger would if you have one. It's not fool proof, to much area to check. I have found them by looking at the engine running in the dark. Not that you'll see a lightning show. Look for halos or small arcing.
4 Distributor clamp ground.
5 Air gap set correctly for reductor and pickup.
6 Coil getting the correct voltage all the time. Bad connections. Bulkhead connection, wires, switches. Bad coil, correct MSD coil? Temporarily. Put a jumper wire from battery to resistor run wire side only. Blue. Take it for a drive. Try on alt stud too.
7 Battery and alternator voltage good?
8 Vacuum advance working.
9 Yes the distributor busing does go bad. Check for play.
Borrow one and swap it out, then you know!

 

[Challenger RTA]

new cam kit put in

Wiped a lobe?

It runs very rough and even misfires/backfires a lot during acceleration.

Choke not opening correctly? Accelerator pump? Carb issues.

 

[Oystercopy]

Thanks for all of that Challenger RTA.. Yes, everything was new/checked except for the distributor. I was hoping to find out exactly how you can tell (if you can tell) when the distributor is actually bad. And again, its the only ignition component that hasn't been replaced, and there were no changes whatsoever in performance when they were replaced. Carb is new as well. Just sold the old one last week, which was never bad. I wish I could "borrow" one from someone, but no one around here seems to do much Mopar. And even if I find someone, the people I know would not be willing to "lend" me one to test with; they're not very friendly that way, unfortunately. So my only option is to order one from Summit or Jegs or someone, but I don't think they're returnable once you've used them. And I have dropped a TON of $$ on this car and trying to be a little conservative with my spending, if possible.
Thanks again.

 

[Challenger RTA]

Below it's not mopar but they work the same.

 

[Challenger RTA]

distributor shaft play

does anyone know the amount of shaft play i should have in my 3874598 distributor? apparently there is what looks to be about an 8th of an inch of up and down play. that seems excessive to me. i guess i should also describe why we are looking at the distributor. we have been experiencing a...

www.forabodiesonly.com

Dave's Place - The Lost Art of Maintaining a Mopar Distributor

 

[Challenger RTA]

There is a Bluetooth distributor. In for a Penney in for a Pound. $500

Chrysler

Fully electronic timing control. Tuned with your smartphone or tablet. Wireless Bluetooth connection

progressionignition.com

 

[Ricks72Chlgr440]

There is a Bluetooth distributor. In for a Penney in for a Pound. $500

http://[URL]https://progressionignition.com/products/ols/categories/chrysler

[/URL]

I am running one of those Progression Ignition distributors and love it!

 

[halifaxhop]

Can be a ton of things, first Mopar electronic?, also you need to see where the distributor curve is at they are all different. Almost sounds like a MP ignition kit was put in, really a fast curve for the strip really and the new ones have clone ECU's that are junk. Are the bushings in it OK also? And also are the ignition components compatible? Mopar module or a clone? Lets start there.

 

[halifaxhop]

How to tell a "fake" ECU from a real one

There are a ton of fake ecu's out there two easy wats to tell at a glance are the height of the transistor, usally the fake ones are around 3/8" high and a real one 5/16 or so. Another way to tell at a glance is if there is printing on the...

www.forabodiesonly.com

 

[Oystercopy]

Thanks for all the replies people. As it turns out, the guy who put the cam kit in now believes we actually DO have a problem with cam timing (which I always suspected) and wants to go back in and check that. Either that he put the cam in wrong (timing) or we may have had a lobe or two go flat since it was installed. Either is a possibility. Will try to update this post once we find out what's going on...

 

[540HemiCuda]

If you have a cam lobe going away, you will likely also have lifter noise due to more clearance than the lifter can account for. Is there? And there are some really cool inspection cameras that attach to your phone that you can use to inspect the cam by pulling only the valve covers rather than pulling the intake. https://www.amazon.com/Inspection-Borescope-Pancellent-Endoscope-Smartphone/dp/B0CC27QRQ6

And do you have an inductive timing light? If so, clamp it to where you can see the flash and drive the car (if possible with it hooked up to one plug wire at a time) and if the spark is erratic, you will see it in the flash.

What ECU are you using? There have been problems with them for decades now.

 

[Ronbo73]

I use a ready to run distributor from Summit. That way I don't have to worry about the ECU or ballast resistor etc. It was just my preference.

 

[540HemiCuda]

Check the curve in that distributor. The aftermarket distributors are usually too slow. They do that for the same reason that most aftermarket carbs are too rich............Both settings are safer for the average installer. But are certainly not optimized for a particular application. Big blocks especially like a lot of initial and a fast curve, usually only limited by the combo's tendency to detonate.

For instance, I have my initial at 26* and it's all-in by 1,800. The bigger the cam, the more initial it will like.
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