47 V8 ignition mystery

[Old Henry]

Prior to starting my 10,000 mile maintenance Old Henry was running fine. I replaced all of the sparkplugs and was replacing the distributor contact points when I discovered that I could not properly gap the points because the peaks on the distributor cam were worn down too much. So, I ordered a remanufactured distributor from Southside Obsolete that looked like new when it arrived. Cam peaks nice and sharp. Since the remanufacture was some time ago I replaced the points with new ones and was able to properly gap them. After installing the new distributor the engine worked even better than before . . . for one short errand. Then it started skipping beats and fairly quickly was skipping a lot - missing cylinders. I put a timing light on the coil high tension wire and the spark was very inconsistent. I suspected possible problem with the new distributor rotor I'd installed so removed the distributor cap and examined it for any damage to it or the rotor. No damage to cap nor rotor. I then suspected the old condenser/capacitor I'd had on for a long time. Removed it and checked it. Still perfect but replaced it with another perfect one. Didn't help. I then took a short drive with the timing light on the coil wire shining in my eyes while I drove. It has smoothed out but some cylinders were still missing. Back at the garage the spark at the coil wire was smooth but at the spark plugs several were very intermittent. I suspected defective wires so last night, after dark, I ran the engine in total darkness to see if I could see any sparks from any wires. I saw none but saw some slight spark leakage from the base of the spark plugs to the block. Took another drive this morning hoping for a miraculous recovery. None. Several cylinders still not firing. It seems clearly an ignition problem but I'm bewildered.

What have I missed?

Any ideas of what else to try?

Any help greatly appreciated. Old Henry is still my daily driver.

[Ggmac]

Thinking , you should not have spark from base of plug to block . Either the blug isn’t completely tightened and grounded or the plug is bad and the spark is following the path of least resistance, the outside of the plug ? I’ve never seen that happen .
Still thinking , good one .

[Lawrie]

Craig,
I always have a spare set up distributor in the 33 .
You should get another distributor from some where and try that, some time the problems take a while to sort.
I would fit new spark plugs ,that is an easy thing.
Try another cap, and rotor.
change the condenser ,
put new fuel in
One thing I found on one of my misfire problems was the little brass straps that connect the points to the round low tension contact were bent out of shape and one was shorting out on the steel part the points spring screw goes into.
Lawrie

[TJ]

I suspect it's the condenser. Recently had an experience with a Chevrolet distributor and it
had some of the same symptoms. Changed the condenser and problem solved.

[JayChicago]

"saw some slight spark leakage from the base of the spark plugs to the block"

Is the gap on the plugs too large? I think should be about .025 for our 6 volt cars. Out-of-the-box plugs are usually much larger gap.

[Old Henry]

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Originally Posted by Lawrie

Craig,
I always have a spare set up distributor in the 33 .
You should get another distributor from some where and try that, some time the problems take a while to sort.
I would fit new spark plugs ,that is an easy thing.
Try another cap, and rotor.
change the condenser ,
put new fuel in
One thing I found on one of my misfire problems was the little brass straps that connect the points to the round low tension contact were bent out of shape and one was shorting out on the steel part the points spring screw goes into.
Lawrie

Thanks for you insights.

I did replace the sparkplugs checking the gap on all first.
I have just ordered new distributor caps (inner and outer) boots and wires.
I did replace the condenser. Didn't help.
I even checked those little brass straps you mention when I was installing the new distributor and bent them away to make sure they didn't touch ground.

[Old Henry]

Originally Posted by TJ

I suspect it's the condenser. Recently had an experience with a Chevrolet distributor and it
had some of the same symptoms. Changed the condenser and problem solved.

Yeah, I've solved ignition problems in the past by replacing the condenser so I tried that first. Didn't help.

[Old Henry]

Originally Posted by JayChicago

"saw some slight spark leakage from the base of the spark plugs to the block"

Is the gap on the plugs too large? I think should be about .025 for our 6 volt cars. Out-of-the-box plugs are usually much larger gap.

I checked the gap on the new plugs as I installed them. They were all correct.

The "glow" around the base of the plugs is, indeed, a mystery I don't understand.

[Old Henry]

Just to make sure the problem wasn't in the new plugs, I switched the plugs from the cylinders that were firing with the ones that weren't. The problem stayed with the cylinders, not the plugs. So, they're all OK.

Because the distributor was creating reliable spark from the coil but the sparks weren't making it to some of the plugs, I decided to bite the bullet and replace all wires, distributor caps (inner and outer), and boots even though I could not see any sparks in the dark from the wires. Hope it fixes the problem. All of those new parts ain't cheap.

Thanks to all who made an effort to consider and advise.

[Seth Swoboda]

Why not send your new distributor so someone like Michael Driskell to time and check out on the distributor tester? When you get it back it will be timed and ready to bolt on.

[Old Henry]

Originally Posted by Seth Swoboda

Why not send your new distributor so someone like Michael Driskell to time and check out on the distributor tester? When you get it back it will be timed and ready to bolt on.

I will probably do that very thing while waiting for all of the wiring parts to come.
What is Michael Driskell's contact information please.

[Seth Swoboda]

Originally Posted by Old Henry

I will probably do that very thing while waiting for all of the wiring parts to come.
What is Michael Driskell's contact information please.

www.thirdgenauto.com

844-327-5988

When you get it back, bolt it on, have fun.

[Ggmac]

This spark plug glow at the base is bugging me . If its still together, I have a simple test you could try . Take a jumper leade and attach to the base of the spark plug (while its in the cyl head and ready to run ) take that leade and attach the other end from the plug base to a solid ground on the motor . What I’m trying to do is eliminate the possibility of the plug NOT BEING GROUNDED when installed in the cyl head . Never had nor heard of this situation, but also never had a glow or spark from plug base to ctl head either .
Just a way to eliminate the potential of it being not grounded. If the cyl starts to fire , we’re on to something.

[Brian]

St Elmos fire? You're not, by chance running resistor type plugs are you Craig?

[pistonbroke]

The glow around the plug base is an odd one for sure, but I'm going with too much resistance in the plug wires. If they are carbon fiber they may have fractured when you did your tune up. Not leaking anywhere just not passing the amount of current if any needed. Just my two cents, Tim

[Seth Swoboda]

If you have carbon fiber plug wires, remove them for the original type plug wires. A second benefit of changing to original is that carbon fiber plug wires on these cars just look ugly.

[35fordtn]

If its a old Reman, the point contact plunger could be froze. Common issue. Also if you replaced the points and used anything except NEW standard FD6770 or Echlin CS47, plan to replace the points. NOS points and other brand points have weak spring tension. Send it in if you need and we can throw it on a Sun Machine.

[Old Henry]

Originally Posted by Brian

St Elmos fire? You're not, by chance running resistor type plugs are you Craig?

Originally Posted by pistonbroke

The glow around the plug base is an odd one for sure, but I'm going with too much resistance in the plug wires. If they are carbon fiber they may have fractured when you did your tune up. Not leaking anywhere just not passing the amount of current if any needed. Just my two cents, Tim

Originally Posted by Seth Swoboda

If you have carbon fiber plug wires, remove them for the original type plug wires. A second benefit of changing to original is that carbon fiber plug wires on these cars just look ugly.

The sparkplug wires I've been using are exact reproductions of the originals with copper cores the same as the ones I just ordered here: https://cwmoss.com/products/spark-pl...e-sets-1946-48

[Old Henry]

Originally Posted by 35fordtn

If its a old Reman, the point contact plunger could be froze. Common issue. Also if you replaced the points and used anything except NEW standard FD6770 or Echlin CS47, plan to replace the points. NOS points and other brand points have weak spring tension. Send it in if you need and we can throw it on a Sun Machine.

I'm sending the distributor to Michael Driskell today to get checked out. I did replace the points with new ones from NAPA that have always worked well for me but it doesn't hurt, as long as I'm replacing virtually the whole ignitions system, to get it thoroughly tested.

[corvette8n]

Professionally fixed and tested it the way to go, I sent mine to CharlieNY and found out the shaft was bent. After being repaired I only had to bolt it on and drive it.