"Master(s), I am puzzled" - Dist. cap question

Hi Guys and Gals! Am trying to track down why I have no spark to the plugs (any of them) on my daughter's '56 Plymouth flat 6. I have good spark at the points, coil tested out fine plus power into it and out of it is there (both circuits). I swapped condensors and found no difference. Good electrical connections all around and all internal distributor wires are good. That leaves the cap. I didn't find any cracks or carbon trails and all tower plug wire and rotor contacts are in nice shape. Did continuity tests from all six plug wire tower contacts to their rotor contacts - all right as rain! However, I tried the coil tower to the rotor ****on and - NOPE! It was then I noticed that the rotor "****on" was actually a small cylinder (backed by a bronze coil spring) made of what seemed to be graphite (I pulled it out of the cap and actually made a pencil-like mark with it on a piece of paper!). I'll admit that electrical is not one of my best skills around cars so please school me, oh wise electrical masters, is graphite supposed to be a conductor and has this one broken down or ???? Many thanks in advance from this unenlightened student! Regards, Dave.

 

Have you tried a new rotor? They will sometimes track internally directly to the distributor shaft and ground out the high voltage from the coil.

 

You got sparkle comin outta the coil wire whilst crankin by any chance? If not no need to play wit da rotor. And yes graphite conducts.

 

Yes the ****on is a conductor. But in all honesty I have not ever checked one with a multimeter, not sure if a meter will have enough juice to overcome the resistance. Remember the coil will shoot out over 20,000volts it will jump any gap that your meter cannot.If you can check another cap and rotor the same way it may help you..
One question for you, Have you checked to make sure the rotor is turning when you crank the motor over. May be a bad timing gear or some such..

 

Thanks for the rapid replies guys! vonDyck: Thanks for the rotor "internal tracking" insight - I will investigate it! Old61: Yes, I have a good spark (will jump a 1/4" gap) when cranking it over. And graphite DOES conduct! Thank you! dalesnyder: Ah yes! Forgot about the 20,000 volts! Graphite must be a very GOOD (not to mention very DURABLE!) conductor! Yes, my rotor is turning fine. Thanks Dale! 440 roadrunner: Yes, a good spark from the coil wire when the engine is cranked plus I had the coil tested by a good local auto electric shop. Yes, I will probably try a new rotor and cap! Thanks!

 

the guy that says to try the rotor is proabbly correct, 40 year ago my spark went down to the metal clip on the inside of the rotor spark in but not to plugs, kinda a flat 6 mopar problem never see it anywhere else
that metal clip is a killer of SPARK!!!!

 

like someone else said..

Make sure the rotor is turning while cranking the starter.

timing chains go when you least expect it.........

then go from there.

 

eugene vik: Aha! So it can be a mopar 6 problem eh? Yes, I actually had a look at that rotor clip just now. I will definitely swap it out! Thanks for your input!
racer67x: I have actually just replaced the timing gears and chain and this is it's first attempted fire-up since. Yes, the rotor spins fine. Thanks for your reply! Regards, Dave.

 

Update: Popped in a brand new rotor today and........nothing! Guess that leaves the cap! Should have picked up the cap at the same time but the rotor was way cheaper with a definite possibility of failure plus, as we all know, electrical items are non-returnable. Will pick up the cap tomorrow. Stay tuned for further developments. Regards, Dave.

 

2nd update: new cap - no change! This is really getting stupid! I went back over everything and when I got to checking the spark at the plugs (screwdriver shoved into the plugwire end and held just slightly away from the plug, key on, and engine cranked with remote starter), my finger slipped off the insulated screwdriver handle onto the shaft and Wow! a shock! Not much of one, but a shock none-the-less. So there is something there even if I see no spark at the plug. The only other thing I can think of is that when I swapped condensors, I took one from what I knew was a working distributor. Other than that, I'm stumped boys and girls! I seem to remember many years ago that the way to test a condensor was to try and short it out against the dist. case. If it didn't spark, it was good - if it did, it was bad. Can anyone confirm this? Regards, Dave.

 

Timing is ????? Put a light on #1 and check the mark..........???????

 

When I was 1st in auto mechanics cl*** in school, the flathead 6 was the 1st one we learned how to set points on.

So, are you still running the 6 volt battery? I presume you have enough voltage.

The most often made mistake with the flathead 6 was timing. If you have spark from the coil, and spark through the plug wires, the spark isn't getting to the plugs at the right time. Multiple sparks through the coil almost eliminates a bad condenser, a bad condenser may fire a coil once or twice, but will fail after a few sparks are delivered. If you have replaced the cap and rotor and are still not seeing a spark, what method are you using to check spark at the end of the plug wire? You need to remove a plug (try #1) and be sure the plug is grounded, with the wire attached, spin over the engine and watch the plug for spark. Unless its turning too slow or you have a bad plug wire, you should get a nice blue spark you should be able to hear and see.

Bring #1 cylinder up on compression and be sure the rotor is pointing a # 1 wire. I'm betting your off 180 degrees. Gene

 

Thanks for the new responses everyone! GMC BUBBA: Timing "SHOULD" be bang on as I lined everything up when I put in the new gears and chain, plus I took out #1 and cranked it over till it spit compression against my thumb and then I checked the crank pulley timing marks and the rotor location. All seemed in agreement. However, that still doesn't guarantee that it's right so I will check the whole thing one more time plus put a light on it to confirm. Thanks Bubba!
50dodge4x4: This '56 is bone stock (with 12 volts) and I have pirated the battery from our '63 Galaxie which is a big one (with lots of juice!). To test the spark at the plugs, I stuck a blade-type screwdriver into the contact of the plug lead's boot and held the metal shaft of the screwdriver alongside the top end of the plug. Then cranked the engine with the key on with a remote starter hooked to the solenoid. As I mentioned before, I saw nothing (at any plug) but did definitely feel it when my finger accidentally touched the screwdriver. I will try the "grounded plug" method you suggest plus (as mentioned above to Bubba) will check the whole timing setup again. You may very well be right that I'm 180 out (and very stupid!) Thanks Gene!
440roadrunner: I'm only holding the coil wire about 1/4" from a bare spot on the block, but the spark is blue and white, not what I'd call "really strong", but definitely there. The timing is via gears and chain, all just replaced. Will check the plugs and timing again! Thanks for your input!

Will try all your suggestions in two days as I became a grandfather (again) yesterday and have to go to the mainland and see my new little grand-daughter!

Regards, Dave

 

Enjoy that new graddbaby.

What condition are the plug wires in? I've seen wires short out through the insolation before reaching the plugs. I went to the spark plug to test wires because often the screwdriver in the boot resulted it the spark going someplace I couldn't see, or the connection between the screwdriver and the connecter in the boot was poor. That and I hated getting bitten. LOL. Gene

 

Maybe this need to go in the tech file for us flat head mopar folks.

Make sure that the coil wire goes fully into the wire tower. Also there is a wierd deal with mopar distributors they used at least three different ones, and the diffeneces are very subtle, but distributor caps DO NOT INTERCHANGE. As you can see in the pic the body heights of the distributors and the distance from the top of the body and the top of the rotors are different. The one on the right is from a 46 Plymouth, the center one is from a 54 Dodge pickup and the left on is from a 56 Plymouth. Also the points can be either above the shaft or below it depending on the dist number.

The short body needs a taller cap, so if you put the taller cap on one of the higher bodied ones, the rotor will not tough the center contact, so the spark will use it's energy jumping the gap in the cap ad have nothing left for the plugs. To be sure pull the dizzy and get the number off the tag, and take it to the parts store and make sure the application is correct. Also what is the engine number on engine i the car, it might not be the engine that came in the car. Not uncommon in these cars and trucks. Should be a P26 starting number for a 56. NUmber is on a pad on teh block above the genny and just below the head. Enigne codes ar P for plymouth D for Dodge T for truck S for Desoto, C for Chrysler (but these are the 25 inch long block) and I for industrial. But that still could mean the dizzy was switched over time. So pull the dizzy and take the nummber off the tag with you when you buy ign parts. Hope this puts you on the right track.

I am running a 56 enginne with a 54 Dodge truck dizzy in my 46. I tried to use the tall 46 cap on the taller 54 dizzy and it made me dizzy till ai had all three on the bench and noticed the difference.

 

i have a 1960 yale forklift with a flat 6 chrysler ind. engine and was having issues from sitting and it turned out to be poor ground to the block. try running jumper cable from dist. body to battery ground, positive if your system is stock and see if their is difference.

 

Did you remove the distributor and reinstall it? It's very easy to get it 180 degrees out of time; in which case, all the component parts will work but it won't run. Someone already suggested using a timing light; that would tell you whether it's backwards.

 

a dist 180 out should still put spark to the plugs. At the wrong time but still thee would be spark.

 

Back from the mainland and our new grand-daughter is a total cutie! Gonna be a foxy lady for sure! 50dodge4x4: The plug wires look fine Gene (mind you, never judge a book by it's cover!). I was toying with the idea of replacing at least one to see if there is a change and I will try the "grounded plug" trick (plus all the other good suggestions) if the rain ever stops here! Non-stop the last three days! Thanks for your further help Gene! plym_46: Read your PM before checking this thread. Thanks for the dist. tutorial complete with pics! Definitely a candidate for the "Tech" file! If the rain ever stops, I will check the block # but believe it is the original engine in a bone stock car (doesn't even have seatbelts (yet!). Thanks for your help! 440roadrunner: So true, unfortunately trying to find a knowledgeable parts guy nowadays is like trying to find a virgin in a cathouse! lol! 55dude: Thanks for the "dist ground" tip! Will add it to my list to try! Arthur1958: No, I didn't pull the dist., just all the plug wires when I pulled off the head. Yes, will hook up the timing light when the sun comes out. Thanks!

And thanks again everyone for your further input! Will post a followup after the flood stops! Regards, Dave.

 

Latest update (Sat. Nov. 21st.). The sun came out long enough for me to try the lastest batch of suggestions none of which, unfortunately, brought any positive results - ****! The maddening thing about this whole problem is that this engine ran like a champ before the timing gear replacement. I lined up the marks on the cam and crank gears (double-checking it three times!) when replacing the gears and chain and didn't touch the dist. during this time as I only removed the plug wires to pull the head to check #1 intake valve. Before I replaced the head, I made sure both #1 valves were closed, the piston was at the top, and that the timing marks on cam and crank gears were aligned.

So, yesterday I went through everything ONE MORE TIME and have come to the following conclusions.

1. The engine is timed correctly and the rotor is turning fine.

2. A good spark is getting to and from the low tension terminals on the coil. There is a decent spark when the coil high tension lead is grounded to a bare spot on the block (it will jump a 1/2" gap).

3. There is a very good spark (white and blue) at the points (which appear to be in good shape) when a screwdriver blade is inserted between them. I also put a test light on the breaker arm which produced a very bright glow. That said, I did notice that WITH THE POINTS CLOSED, I couldn't get a test light to glow at the point contact opposite the one on the breaker arm. COULD THIS BE MY PROBLEM?????

4. The replacement dist. cap and rotor I bought are exactly the same (visually and dimensionally) as the old ones.

5. There is no spark leaving any of the plug wire towers on either the old cap or the new one.

6. When I swapped condensors, I used one from a dist. (Ford flathead) that I knew was good. It was an Echlin ("Made in Chicago" stamped on it).

The above conclusions lead me to the remaining possibilities:

1. Somewhere in the dist. there is a short.

2. The condensor that I thought was good, is not!

That's about it guys! Any more thoughts, theories, or suggestions?

Many thanks in advance!

Regards,
Dave

 

My take on the entire problem after reading every post is :

If the engine ran well before the timing chain and gears and now wont start, THEN we have a timing problem. Many after market gears are installed wrong and i have certaintly fought a few of them.

If ya feel that the distributor does in fact have a problem, i can offer this....
Ship me the distributor and coil. I will dis***emble ,clean , adjust and test the distributor under load on the distributor machine and return for no-charge other than shipping.

If that helps ya get er to me.........

www.bubbashotrodshop.com

 

Take GMC Bubba up on his offer.

You mentioned rain and lots of it many times, Any chance that you could have moisture related problems ?

Its difficult to remember but when a new problem shows up one should always look at the last thing that was fixed first. Not always directly related, but work done maybe in the proximity of the new problem.

If you have spark out of the coil and it does not come out of the distributor then your problem starts at the coil end of that coil wire. Check everything methodicly and one piece at a time.

Also remember that new parts are not without flaw, JUST because they are new doesn't mean they are in good working order. Unless you are doing a complete rebuild Never change a part unless you have deduced and proven that it is in fact bad, that only leads to frustration and blows the beer money.

 

I would take Bubba up on his offer.
If not, how about cutting the old distributor cap in half from top to bottom.
Then you could look inside and maybe see the problem.

Is there any chance a Ground wire or strap got left off when you did the motor work?

 

Bubba: The gears and chain were NOS from Andy Bernbaum's, although I guess NOS can be wrong too at times! Thank you for your very kind offer! If I can't find anything with the latest round of help, I will definitely take you up on it! 31Vicky with a hemi: Good point with the "moisture" observation! That possibility did cross my mind early on but I haven't noticed any evidence of any when removing the different parts multiple times (interior of cap, wire connections, etc.). Yes, a check of each component from coil wire all the way to and including the individual plug wires is in order. I'm not always good about proper "piece by piece and in order" diagnosis and often just jump to the main components as possible culprits. You'd think I'd have learned after all these years! Thanks for your input! 440roadrunner: Good stuff! Many thanks! I will try each and every one! No, unfortunately there are just about no good parts people left in my area and I couldn't have got my parts from the dist. number. Just young kids who don't know past the not-so-far-back listings in their catalogues and don't know spit about older vehicles! That said, at least the young gal who served me did go in the back and manage to find an older listing for my car. The replacement cap and rotor are BWD Engine Management Technologies (which I THINK used to be Standard and/or Niehoff???). dale snyder: Yes, Bubba will be my last hope! Good point with cutting the cap! (I almost feel like cutting up the whole car but my daughter would disown me plus the guilt afterwards would kill me!). No cables or straps not hooked up. I did replace the front engine mount biscuit which meant that I could remove the chains on either side of the engine that a former owner must have put on to control engine vibration! Thanks for your help Dale!

And thanks again everyone! The HAMB ROCKS!! Stay tuned for the next installment! Regards, Dave.

 

Lets do one more test ..........
Take a compression test,,,,,,,,,,,,,good compression cam is correct timing,,,,,,,,,low or no compression is ( or could be) cam out of phase............

Bubba

 

A good trick for checking cam timing (to double check or verify your timing marks) is to lay a short straight edge across the intake and exhaust lifters of #1 cylinder. You need to be able to determine when #1 piston reaches TDC. Turn engine over by hand until exhaust lifter is almost completely down while the intake lifter is beginning its upward movement. Lay straightedge across tops of lifters - should sit flat on both lifters AND piston must have reached TDC. If the piston is not anywhere near TDC, your cam is timed incorrectly. Also your distributor rotor should be pointing to #6 cylinder when #1 is on valve overlap. Is your diz perchance a 1/2 turn out?
BTW, the straightedge method was what Chet Herbert instructed his cam installers to use to "degree" his performance cams. (I prefer the dial indicator and degree wheel/lobe center method myself).

 

Sorry Guys! Haven't been on for a while (putting up Xmas decorations in-between all the rainy weather!) Bubba: A compression test? - GASP!!!! That's what started this whole mess off in the first place! But then it was my fault with too long an adapter on the plug end of the tester hose! OK, I'll TRIPLE check the adapter length this time! Thanks! von Dyck: Thanks for the new method! I did verify TDC (on the compression stroke) with both valves closed and the timing marks all lined up when the head was off. No, the dist. rotor is bang on and has been checked multiple times.

To everyone - latest update Mon. Nov. 30th: Tried the last round of help to no avail! The plug and coil wires are all the carbon-filled (radio resistor) ones so I tried replacing the coil wire with a solid core and tried to get the test probe down between the wire and the tower but couldn't get the test light to glow. Even at that there was no change with the new wire. I may need a thinner probe or something to reach down all the way - I was getting VERY discouraged at this point! I pulled the dist. and took the top end apart (points, condensor, closely checked wires for breaks in insulation, etc.) but only found the points were pitted which dressed up nicely with a point file. Close measured the caps and rotors (old and new) and all were fine. All cap's rotor ****ons are hitting the tops of the rotors and rotor ends are very close to all plug tower contacts. I'm ready to give up! Maybe I need to take a sabbatical until the new year! Thanks again everyone for all the suggestions! Regards, Dave.

 

Please stop testing stuff (primary ignition) that is PROVEN to WORK!!!
If you have a nice spark out of the coil wire to ground when you are cranking it over, this proves that the gears are turning inside, that the coil, points, condenser and the distributor are working. What you are lacking is the distribution of that spark!
The voltage goes from the center of the coil through the coil wire (All proven good!)into the center terminal of the cap, to the rotor. The rotor aligns with the correct spark plug cable tower and the spark jumps the gap between the rotor tip and the tower contact. If the cap and rotor are not touching in the center, it will have to jump. Check this by placing a little dab of grease on the center of the rotor and installing the cap. Remove the cap and check to see if the grease has been disturbed and transferred to the cap. Clean off the grease!
Next, the voltage can follow a carbon trail on the cap or the rotor to ground. New correct parts should solve this.
Next, the cap and rotor may have too much of a gap at the tip to let the voltage jump. Correct parts should also fix this.

 

I agree. Everything has been checked so many times, its got to be frustrating.

The problem has to be between the coil wire post on the distrubitor cap and the wire posts on the cap, or bad plug wires. It can be no place else. The issue is cap, rotor, or plug wires. Incorrect timing may keep it from running, but will have nothing to do with getting the spark to the plugs. Without spark at the plugs, it will never run.

Plug wires are a pretty simple test, they are either good or their not. At this point, we are only concerned that current can go through the plug wires.

From this point, make sure the coil voltage can go through the coil post on the distributor cap to the top of the rotor. A simple test light connected to a power source and grounded on the insid of the cap will determine this. All you need is to have current flow through the coil post.

Next, check the same thing on the plug wire posts. Again, all we want to know is if current is going through the plug post(s).

If boh of these are good, all that is left is the rotor and the air gaps. He told you above how to test the air gap at the top of the rotor. Do that. You can also check the air gap at the rotor end and the plug terminal inside the cap by the same method. Apply a little grease on the end of the rotor, install the cap, turn the motor over by hand 2 revolutions and see that each post has some grease on the plug post. If in doubt add some grease at each plug post and see how thick the grease is built up. Be sure to clean up all the grease.

If everything tests good, the rotor has to be shorting out to ground.

I'll bet when you get this thing figured out, you will never forget it. Gene

 

Since all of this makes no sense to me, let me ask all the experts a question..
Is it possible that the rotor tip is not aligned with the distributor cap contacts when the points are fireing.. For example the rotor is in between two posts on the cap when the coil is fired. Can this happen somehow. I have never seen it. It would explain the mans problem.