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Resolving No Spark redux


wagoneer
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I’ve come to terms with the limitations of my own abilities and beating my head around a problem with the ignition not sparking even though it did earlier. Alas that is not the foca point but rather sometimes you just need to pick up the phone and phone-a-friend or pay a mechanic 2-3 hours to solve the problem and tech me.

 

Problem is none of my local mobile mechanics wants to work on our classic cars as they don’t know them.

 

Anybody in the Raleigh NC area that can help me out for an afternoon of beer and wrenching, or know a mobile mechanic in this area?

 

What do you do when you need help? Id rather not tow it to a shop if I don’t have really really have to.

Edited by wagoneer
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If you can take a break from the problem for a while that might help. Clear you head. Find renewed interest maybe? I tend to stop, drop and read. Double down and research the theory so I can think logically and problem solve my car troubles. I am not a mechanic. I am just stubborn and cheap so my cars have never visited a garage. Time and tools. I can throw tons of my time at a problem. My hourly rate is free. If I need a tool, I find a way to get it. 

 

Although I have been to Raleigh NC, I live a long ways away. Otherwise I'd love to come an help you out.

 

Is it your 1950 Chrysler that won't spark sometimes? Do you want some more tips on what to check?

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Here is a simplified diagram of how the ignition system works.  And a color coded way to check the distributor for shorts that I put together in an earlier post trying to help someone with a similar problem. Maybe this will help.

 

  Orange - This wire is there to ground the body of the dist to the points plate.  Check for continuity.  

 

     Yellow - Check this with the points open.  The wire from the coil to the points, the copper strap from the condenser to the points and the points should not be grounded to the body of the dist.  The copper strap should be insulated so it will not touch the dist body.  This could be done with heat shrink tubing. 

 

     Purple - There is an insulating bushing here to insulate the points from the body of the dist when the points are open.

 

     Red - This is the wire from the coil to the points.  It appears to be there but it is stuffed down in there somewhere.  Reroute or replace this wire so that it does not ground to the body of the dist.

 

     Blue - This is where the wire from the coil connects to the dist.  Check this through connection to make sure it does not ground to the body of the dist.  You may consider replacing this wire also.  It looks a little worn.

 

     Green - This area looks a little tattered.  When you reassemble the dist I'm sure it will look and function better.

Ignition System Go By.jpg

Carl's Distributor With Comments.jpg

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Thanks guys. The funny thing is that after 8 months, I put it back in as original and it fired pretty much right up

 

See this beautiful first start up: 

 

 

I then proceeded to try to tighten it and it stopped starting up for some reason.

 

Then it wouldn't start and I got a huge backfire - 

 

 

That was it. Then I tried again and no spark.  I tried flipping it 180, I tried tighten the connections, even replacing the lead from the ignition coil.

 

 

 

I'll try to bench test it next but I'm running out of time, which is why I would prefer to some seasoned experienced hands...

 

 

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What exactly did you "tighten up"? Just the coil connections? Does this car have Prestomatic or just Fluid Drive? There is a mechanism to kill the spark on downshifts with the former; maybe a short in that circuit? Check the inside of the distributor cap. Is the little button that contacts the rotor intact? If all that is okay, double check that the points are opening.

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Do you have a volt meter or test light?  Start with are you getting power to the coil?  If no, then problem upstream.  Pull the distributor and find number 1 tdc on compression.  At this rate, based on the poor quality of ignition parts, you might want to try a new condenser and possibly new points and set the gap.  Examine the small wires in the distributor and make sure they are not broken/frayed or otherwise grounding out (except for the ground).  Reinstall the distributor with the rotor pointed at the number 1 cylinder and make sure all your wires are in the right firing order.  You seem to be almost there without needing to get someone to come out.  On a side note, on the timing video, idle seems high, and there is likely a chance you were into the mechanical advance at that point.

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  • Solution
On 8/18/2022 at 12:52 AM, joecoozie said:

Your right it’s 12 BTDC not after.
 

I decided to bench test my distributor and it works as expected ; that tells me it’s a wiring issue. I was getting an issue with very intermittent spark like on the car; i checked some grounds and adjusted the points gap a bit , and I think I had power reversed and voila 

 

 

 

tomorrow we get the whole car to fire up.

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8 hours ago, Sniper said:

Better double check that dwell, it seems awful low.

It does look low and I was going to adjust it more but it’s set right on 20mm. At 18 it was having issues and I’ve had it higher so I’m second guessing my dwell reading .  I’m getting myself a bt-162 native 6v dwell meter on eBay for conclusive.

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20 mm?

 

 

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3 hours ago, wagoneer said:

20mm

 

First, there are no specifications listed in the FSM that involve anything metric.  You probably meant 0.020"

 

Dwell is specified as 34.5 to 38 degrees, so one of those two measurements is off, either the points gap or the dwell reading.

 

 

 

 

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@Sniper @DJ194950 yes I meant 0.020 inches per the book and the feelers.


I got some time to look at it last night again, and an interesting observation occurred:

 

After experimenting and taking out unnecessary connections to confirm spark, I think it comes down to a grounding of the distributor issue (my current theory).

At which point is the distributor grounded to the vehicle and what is the purpose of the cork casket shown in the pictures below? 


 

After installing distributor, double checking spark plug wires, and coil wires are tight - a test start produced after a few rotations a giant boom right out of the carburettor but that’s about it. It sounded like it almost wanted to start, but then nothing afterwards. (Square one)

 

I simplified the system to do the same bench test method but with the car as the platform (engine rotation instead of drill, starter, and car wiring, etc). - I removed trans relay connections and I connected the coil directly to a spark plug that I grounded directly to the engine ground …. Nothing - no spark. 

tried with a second coil … nothing.

 

The only thing that I can think of now is maybe the distributor ground - is distributor grounded like in my experiment.

 

 

There is a small cork gasket at the base of the distributor I guess to provide insulation against the body . I had before in my failing experiments and in the mean time it disintegrated.I  made a replacement out of cork sheeting though  I suspect the distributor is NOT grounded .

 

Maybe that is why I'm getting intermittent spark on first install and backfires? Grasping at straws...

image.jpeg.68fa8d904230ae29923244bfb5d4d876.jpegimage.jpeg.fa7c30aad827f3f6190be136b37827f1.jpeg

 

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The timing plate that bolts to the block and distributor is your ground.  the cork gasket is there to prevent oil leakage.

 

If you are backfiring you either have the timing off or a valve hanging open.

 

A compression check will sort out the valve issue, if any.

 

You can always add a dedicated ground wire to the distributor, or even a jumper for testing purposes, to sort out any distributor grounding issues.

 

I still say your dwell is way too low based on the meter readings

 

 

 

 

Edited by Sniper
typos
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3 hours ago, wagoneer said:

After installing distributor, double checking spark plug wires, and coil wires are tight - a test start produced after a few rotations a giant boom right out of the carburettor but that’s about it.

 

After reading through the post ..... are you certain you did not remove & re-install the plug wires in any way from the distributor cap ... or plugs?

 

It is a common theme that #1 plug wire goes at 7:00 O'clock on the distributor cap.

This is only true if the last person to disassemble / re-assemble the engine installed the oil pump correctly.

 

This was my mistake when I first bought my truck & looking for first start.  ..... The wires were shot, I ripped em off & tossed em in the trash.

When the new wires arrived I looked at the pictures in the book & installed them .... #1 @ 7:00 'clock.

I felt confident I knew how to follow a picture & never mentioned the new wires while trying to troubleshoot the no start.

 

The distributor is slotted & either right or 180 out.

The oil pump is geared. If it is installed 1 tooth off, this moves your #1 plug wire on the cap .... mine is at 6 O'clock others are at 5 O'clock or even further off.

 

I'm only suggesting this is one of those gotchas you need to be aware of.

It really does sound like a miss location of wires backfiring through the carb.

 

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Yes the distributor housing is grounded. It is supposed to be. The entire block is grounded. Anything metal that contacts the block is grounded. Ground can be explained as simply the return path to the battery. The small wire from the coil cannot touch anything metal (ground), over the entire path from the coil to the breaker plate. This is the plate that holds the points, inside the distributor. The wire fastens to the breaker plate via the little tab sticking out of the side of the distributor. Is is isolated so it cannot make contact with ground. 
 

The little coil wire cannot make contact until the points precisely allow it. When the points close, the wire from the coil is connected to ground. If the exact millisecond that the wire is supposed to contact ground via the points is wrong, things don’t work right. A Boom out of the carb is a possible result. The Piston is supposed to be on stroke 1, travelling down. Intake valve open. Fresh mixture of air/fuel is being sucked in. The spark is surely not supposed to fire at this point. If it does boom! Combustion yes, but escaping noise and exhaust gases head up through the open intake valve, via the intake manifold to the carburetor.  This is a clue that your timing is wrong. Yet could it be valve timing? Timing chain sloppy? Broken? A sprocket retaining key sheered off? Put #1 at TDC, using timing pin hole and wood dowel, over #6 cylinder. View the valve tappets and lash. Are both valves fully closed? Do both tappets have some up and down wiggle room if you grab them? Both should. How much? The published spec amount of valve lash.  
 

Do you have a multi-meter? Use continuity setting. Check for path to ground at little wire from coil to distributor cap.  Confirm the wire only contacts ground when the points close. Perhaps it never contacts ground. A clue! Points are set too wide, not closing maybe.  Points set too close together? Not enough dwell time. Also no-bueno. 
 

By chance do any of your spark plugs show hairline cracks in the porcelain? How about up inside the distributor cap? Carbon track line? 


Saying that, the #1 thing I tell people to do first when troubleshooting a flathead Mopar: Compression Test. The results will guide you where to go next. 

Edited by keithb7
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  • 4 months later...

I've been away for a while, and I finally got to get back to this problem over the break, and I went back to basics and read the manual again. Lo-and-behold their are pearls of wisdom in the manual as well as the MTSC guides specifically the one on electrical system.

 

I tested for amps with ignition on to test the coil - seemed a bit low, so replaced it with another one that I had.

 

I took out the distributor and tested for internal continuity - across the points - zero ! Points were burned. I took them off and cleaned them up and verified continuity with points closed, and not with points open. 

 

Plugged it back in; verified wires going to right spot, and took one plug out and grounded it -- SPARK!

 

IMG_2231.png.e634589e5c064e1b39263191a8c15234.png

 

Oh happy day!

 

Plugged it back in, verified wires tight, connected my 6v timing gun (super rare find). 

 

 

 

Turns over and almost wants to go but not quite

 

IMG_2232.png.70690b5d50b056318b119a828a3a80bd.png

 

 

You can see the timing is waaaay off. The top white mark is +2 BTDC, and bottom white mark is about +12-14 BTDC ( where it was before).

 

I futzed with the dizzy rotating it around but couldn't get it to quite turn over (verified gas flowing).

 

Back to the book - I need to statically time the dizzy

 

 but one thing that is very annoying is my oil filler pipe gets in the way of rotating the dizzy and the vacuum advance nozzle hits it! My  BTDC is something like around 6 o'clock, but my dizzy is timing at +12-14. 
 

I suspect I may be 1 tooth offset on the oil pump b/c I don't have the rotational space to connect set it back to TDBC statically or with timing gun and points firing. 

 

There was a point in the other thread stating you could set TDC to whatever, but I think you are limited in where you can set the oil pump / dizzy teeth alignment b/c the oil filler pipe gets in the way.

 

 

Also it was super cool to use the timing gun at night.

 

2 steps forward. 

 

 

 

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