Help Me -before I go mad

[Karl]

Its not often I'm completely lost but this is it

I have been chasing an intermittent miss in the 34 which I can't find
Completely stock set up 6V Mike Driscoll Distributor Skip Haney Coil Uncle Max rebuilt Stromberg 48

Its a long story but I have completely hit a brick wall and I really need some help. I have had an intermittent miss for last 4 months intially was just a slight stumble at speed but has got progressively worse. A couple of months or so ago after 5 minutes driving the car began to buck and miss and even with full gas 30 mph was the most it would go As I slowed down to pull over died completely and would not start . My wife towed me home.

Found I had 4.3 Volts to the coil but absolutely no spark . Ok That's easy Coil or condenser. Since I have no way of testing the coil and on a 34 Taking the coil out is the easiest way to change the condensor I changed out both with a condenser that tested fine and a new Skip Haney Coil . Started right up but still continues to miss. Slightly lumpy at idle . but good spark to the plugs I have changed the condenser twice . I have changed the Distrib Caps , I've changed the plugs . I have checked and rechecked

Yesterday It did same thing (in the same place) after 5 minutes on load missing badly jerking and jumping and max 25mph at full throttle I pulled the choke didn't improve but back fired . After about 4 mins of this it came right . Tonight in the garage I have run it in the dark no shorts anywhere that I can see. I removed the plug leads and I have A nice juicy spark that jumps at least 1/4 inch to each plug. Suggesting to me that the ignition circuits are ok and the condenser/Coil is good

I did notice some garbage in the fuel pump bowl (Mike Driscoll rebuilt Fuel pump with a bowl) I have installed a fuel filter and Cleaned out the carb and all the carb lines even tried running my spare 97 and no improvement.

The only thing I can think of now is the plug leads or perhaps the surpressors on the leads for the radio -However I just can't see that multiple leads would all fail together -and then come right.

Have no idea what to do next

Help -Karl

[fordscript]

Sounds like might be the rotor....old originals do go bad, new repros are suspect. 4.3 at the coil is low enough, what is the generator charging? I don't know, but are Skips coils built to be 4.3 volts or 6? Just a thought.

[Mart]

I'd also be looking at the HT side of the ignition. The HT loads need to be low as the spark will try and find the path of least resistance. If you have resistor plug caps, ditch them. Make sure your plug gaps are at .025" no wider. On a helmet, the most likely culprit is the rotor. A new rotor, along with losing the resistor caps will probably fix it. You can put a couple of layers of shrink tube on the distributor shaft to help stop the rotor/shaft spark leak path.

My experience is mostly with the crab distributor but all the same things apply.

Mart.

[50droptop]

Agree, it’s likely the rotor. There is one more thing you can check on the helmet; the screw that sets the advance on the breaker plate. I had a similar situation and found the screw was stripped, allowing the breaker plate to move slightly. Sometimes it was fine, other times it wasn’t. While checking the rotor, be sure to check that screw as well.

[Terry,OH]

Remove the radio condenser at the ignition coil and check again.

[PeteVS]

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If it's missing while idling, try pulling the wires off the plugs one at a time to find the cylinder that doesn't make it slow down.

[Frank Miller]

Check your ignition switch and wiring to the coil. A loose or bad connection can cause what you describe. It might be getting worse as it heats up. Also if you have one of those resistors that varies with heat I'd look at that too.

[David J]

I have used Champion UD16 plugs for testing spark .
They have hollow stems and you can see the spark when running .
Easy to see any weak-dead ones .
Also easy to see if any intermittent spark .

On a completely different note my 34 was cutting out and losing power .
Couldn't find any obvious issues until loosening the gas cap cured it .
Never had that issue before and it turned out to be a plugged vent on top of the tank .

[Don]

Ever check for plugged exhaust!

[mcgarrett]

I'm sure you've checked it, but you mentioned you saw some trash in the fuel bowl. Are you sure you have good, strong fuel flow with no restrictions? I have a '31 Model A that was acting the same way as you describe; driving along smoothly then started bucking, backfiring, spitting, and finally dies. The trouble was trash, rust particles blocking good, strong fuel flow to the carb. I had to install a fuel sediment bowl to strain out the rusty stuff. Once I got the fuel to flow properly, it runs fine.

[51 MERC-CT]

Have seen similar conditions that were due to a cracked cork sediment bowl gasket (was sucking air not fuel)

[alanwoodieman]

remove/change the rotor, while you are at it insulate the shaft with shrink tubing or electrical tape

[deuce_roadster]

One more thing to check would be swap out the resister. It could be broken but making a connection enough to run but when it heats up breaks the circuit to the coil. Get a jumper wire with alligator clips and hot wire the coil from the hot side of the starter switch at the bottom of your steering column and see if it runs fine. That would tell you if it was the switch or resistor assuming no shorts in any of the wires.

[Kube]

I had a similar thing occur on a clients '40 a few years back. Pulled my hair out trying to find the culprit. Turned out to be one bad spark plug. Nothing visible amiss and ran perfectly when cold.
In all my years, that was a new one to me.

[uncle buck]

Originally Posted by alanwoodieman

remove/change the rotor, while you are at it insulate the shaft with shrink tubing or electrical tape

Can somebody post a picture of what is being suggested here?
Thanks, just trying to visualize it

[Hoop]

This is a worn shaft and that's masking tape ... all used to illustrate where the shrink tubing or elec tape would go.


distshaft.jpg

[Old Redneck]

The Coil Wire can drive you crazy. Do change it and test drive I seen that before. You want a solid wire not carbon wire.

[drolston]

Definitely not carbon "resistor" ignition cables. The cheap ones are also affected by humidity so that the problem changes with the weather. If you are running the spark plug wires through tubes, you may not be able to see the shorts, even at night. You can use the coil wound wire center ignition cables to for radio suppression without causing spark problems. Be sure to get 7mm spark plug wires, not 9mm, or you will have problems getting them to fit.

[tubman]

Originally Posted by Old Redneck

The Coil Wire can drive you crazy. Do change it and test drive I seen that before. You want a solid wire not carbon wire.

I had something like this happen as well. My very original '51 came with this black bakelite cylindrical doohickey in the coil wire. I think it was a suppressor of some kind. I started having intermittent problems, so I pulled the coil wire and replaced it with a chunk of Packard 440, which solved the problem. (The doohickey had a Ford part number on it.)

Not that this has any bearing n the O/P's problem, since the '34's had an integral coil, but I thought I'd mention it anyway, on the chance that he has installed an adapter and remote coil.

[solidaxle]

All good suggestions, but you're chasing your tail by taking short cuts. Why not do a compression test and hook up a vacuum gauge and go from there.

[Admiral]

I've had similar issues in the past with a crab-style distributor. One time there was electrical arcing through a bad reproduction cap. This was an easy fix, just replace the cap. Another time I didn't notice I had the spring/contact strip of one set of points touching the distributor backing plate, which caused it to short out, leading to all kinds of drivability problems.

[petehoovie]

Starting at your 5th paragraph - What 51 MERC-CT said in post #11 - "Have seen similar conditions that were due to a cracked cork sediment bowl gasket (was sucking air not fuel)."

I have also found that neoprene gaskets used at the sediment bowl do not seal as well as cork gaskets and are prone to leaking very easily....

[uncle buck]

Originally Posted by Hoop

This is a worn shaft and that's masking tape ... all used to illustrate where the shrink tubing or elec tape would go.


Attachment 429723

Thank you. It's been several years since I had my distributor apart. I had forgotten that the shaft was that way

[Karl]

Originally Posted by solidaxle

All good suggestions, but you're chasing your tail by taking short cuts. Why not do a compression test and hook up a vacuum gauge and go from there.

I Agree fantastic suggestions and has given me much to think about.
Vacuum test is a steady 18-19 inches a little low but has always been at that fiqure Compression equal across all the pots

Karl

[35fordtn]

Karl,
I’d certainly try it without the suppressors and a new set of plugs.

[dumb person]

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I have had this twice.
Once was a points plate not grounding well.
The other is a small amount of movement in the shaft. But it is not worn evenly. Almost like water got in and must have corroded only a small part and now it has movement, but only in one direction

This may or may not prove to be useful in your case.

[Tinker]

It's interesting. Running "solid" copper plug wires I'm guessing also. Which is what you want.

Could be fuel or a blockage/jets too small, since Idle is good and vacuum at idle.... but at top speed, no good. Could rig a vacuum so you can see it in the cab.

But you mentioned that it stalled and wouldn't start till later, Since you replaced plug and condenser. Try a new coil. Rotor or caps could be an issue.

Hows that for narrowing it down!! Best of luck! Post what you find out.


.

[Mart]

Stopping and not being able to restart until it cools down is a typical HT ignition failure. Had it with rotors and caps on a crab.
Actually I had a helmet that did that but I swapped it out for a crab and never got to the bottom of the failure.

Mart.

[Old Redneck]

Did you try another coil wire? Just because it looks good does not mean it is. A coil wire can drive you up a wall. I know first hand.

[Kube]

Originally Posted by Mart

Stopping and not being able to restart until it cools down is a typical HT ignition failure. Had it with rotors and caps on a crab.
Actually I had a helmet that did that but I swapped it out for a crab and never got to the bottom of the failure.

Mart.

Mart, I've been following this thread as well, I feel for the guy knowing first hand how frustrating this can be.
I agree with you 100% in what is probably the underlying issue.
However, and to reiterate a bit from my previous post, I had ONE car, a '40 coupe that acted exactly this way. It turned out to be one bad spark plug.
Yeah, we are grasping at straws here...

Ooops, just remembered one other nightmare I'd experienced that sounds a lot like this one. Car, another '40 would run for a bit and cut out just like this one is apparently doing. Turned out (after pulling most of my hair out) that a small piece of fuel tank coating had come loose and would get sucked to the pickup tube within the tank.
Engine would kill and after a while, it would start up again. Little while later, same thing...
Once the vacuum within the fuel line had dissipated, the piece of coating would let go of the pick up tube.

This car demands a very methodical approach to diagnosing the issue.
Seriously - I'd love to have this one in my shop.

[35fordtn]

Originally Posted by Kube

This car demands a very methodical approach to diagnosing the issue.
Seriously - I'd love to have this one in my shop.

Mike I agree, I wish I was closer to him! Given I built his distributor and FP, I am following this closely.

[Bruce_MO]

I'm with Frank Miller... had a similar intermittent spark problem. It was a loose connection at the resister/fuse block.


Good luck!

[Brian]

And from out of left field.....heat riser blown out in the inlet manifold...I experienced this, took me months to figure out....I changed everything electrical numerous times, so convinced was I that it was electrical. Like you, just about drove me mad.

[Hoop]

Karl,

Is this an original '34 distributor with original style strap points?

[35fordtn]

Originally Posted by Hoop

Karl,

Is this an original '34 distributor with original style strap points?

not to answer for Karl, but according to my computer records he has a Early with 11A internals built Feb of 2019

[FlatheadTed]

If can be many things but as suggested wire and alligator clips top of list , On a day out my 35 Coup had to be push started , as soon as I got back to the shop I hot wired it and it started right up after investigating I found a loose wire on the back of the switch ,the stud was not threaded right up ,for the sake of a little split washer .So voltage drop when hot ,

[Karl]

Originally Posted by 35fordtn

Mike I agree, I wish I was closer to him! Given I built his distributor and FP, I am following this closely.

Michael Most of the stuff on it is yours anyway so I trust it-Karl

[Karl]

[QUOTE=Hoop;1885102]Karl,

Yes -Karl

[Karl]

Originally Posted by 35fordtn

not to answer for Karl, but according to my computer records he has a Early with 11A internals built Feb of 2019

Sorry Michael I swapped it out for the old distributor . Which was running fine previously - made no difference -Karl

[Karl]

Just an Update
In desperation I took it to my normal shop to have it looked at . Normally I avoid that because even though my guy is pretty good most shops really struggle to understand the ignition system but just couldn't see the wood from the trees . He thinks he fixed it . What he did was monitored the voltage to the coil when he was driving with some long leads Apparrently the voltage would suddenly flucuate widely as he was driving .He found that one of the wires to the sensor for the Chex Oil Pressure sensor was hanging loose and was he suspected shorting out . He fixed this and it was all good on a test drive . However I had removed the Chex gauge as I was suspicious of it and replaced it with the normal ammeter . Hence the wires to the sensor were an earth wire and and a live feed which was not live anymore (unless the bare end of it was touching something hot under the dash) He also backed off the vacuum brake a little . I will test the car tomorrow -I'm not greatly hopeful but will see tomorrow -Karl

[BUBBAS IGNITION]

Cant believe no one has suggested a faulty condensor 11 a misfire and then a stall , then a restart looks like a condensor breaking down for sure to me !!!!!

[Terry,OH]

Bubba: In post #1 he replaced both the coil and ignition condenser, he did mention he had radio suppression so in post #5, I suggested he remove the radio suppression condenser on the coil and try it again. I agree it sounds exactly like a bad condenser. Years ago I bought a couple of ignition condensers from Mac's and both were bad out of the box. I am wondering what ignition condenser you use for the 33-36 distributor? By the way I no longer use Mac's condensers.

[tubman]

In case anyone i9s interested, we are just finishing development of a replacement '33-'36 condenser. These are made from scratch to the same standards as our "Trash Can Condenser" (which has proven to be very reliable over the last 5 years). It seems that replacements are available for these but they are of very inferior quality.

After a couple of false starts, I think we now have a quality product.

[FlatheadTed]

Karl ,We see these problems almost daily in our shop ,here's one

[Phil Gillespie]

Originally Posted by FlatheadTed

Karl ,We see these problems almost daily in our shop ,here's one

Ted send it down south, I'd gladly work through it over 10 years!
Great looking car
Phil NZ

[Karl]

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Originally Posted by FlatheadTed

Karl ,We see these problems almost daily in our shop ,here's one

Ted after things settling a little the problem is back but not as bad.
Almost everything I could change has been changed The only thing left is the spark leads -I have a set of on the way from Michael Driskell so will put those in and see how we go. -If that doesn't work I'll take a week off work and drive it up to Auckland and let you sort it -Karl

[Karl]

Finally I think I'm getting somewhere. As mentioned by a few posters here already I think the problem is on the radio interference resistors on the end of the spark plug leads. I have noted that when i have been pulling the plug wires off to check for spark when running I have been getting a shock through the resistor bodies on some of them. Today I replaced them with a new set of NGK 5000 Ohm resistors. Just for interest I checked the resistance on the old resistors they were all over the place they ranged from 9000 ohms to 48000 ohms -not sure if this is the cause off the problem but seems to be running better .

[koates]

Karl, I think you have hit on something here. 48000 ohms is way to high. I have the original type right angle plug resistors on my 34 Ford and they are rated at 15000 ohms which is about a standard for these units. Never had any problems with them and the glove box radio works great. Regards, Kevin.

[Tinker]

Karl, you going mad yet?

[Karl]

Originally Posted by Tinker

Karl, you going mad yet?

Yep getting worse Missing back again . The next step is to replace the Spark plug leads with a new set from Mike over this weekend and see what happens then. I plan to replace them with out routing them through the conduits until I'm sure that they fix the problem.

If that doesn't work then I wonder about fuel starvation (as my mechanic did blow back through the lines (as well as fiddling with what he thought was a short) and was good for a while that is he thought he had fixed as it drove ok for 20 mins ? Coincidence ) if there is some gunge in the tank I guess it could block the fuel uptake - So the next time the missing and bucking starts I will pop the clutch turn the key off and coast to the side of the road - and then see if the fuel pump glass bowl has an air gap at the top

If that doesn't work then I'll buy a Chev! -Karl

[tubman]

Karl - Please don't go to that length. You may be on to something with the "gunge in the tank" theory. I had exactly that problem with a '36 I bought about 30 years ago. Until I was able to get around to dropping the tank, etc. I found that if I never let the fuel level go below half a tank, I didn't have the problem. Whatever it was must have been mostly floating around in the tank and if there was enough gas, it kept it away from the pickup.

I also had a friend who was able to score a very nice '67 Nova hardtop with the same problem. Sure enough, there was a rag in the fuel tank. That was the good news; the bad news was that it was a 6 cylinder/Powerglide.

[Mart]

Ok I'll give my opinion.

If you consider the ht side of the ignition as "weak", in other words, the spark will try and go astray before getting to the plug, try and reduce resistance where possible.

Solid core wires, solid connections to the plugs, (no resistor caps) and spark plug gaps no more than .025".

This will give the spark the best chance of ending at the plug tip instead of finding an easier path somewhere else.

If the cap, or rotor have been compromised and have been giving problems, they will probably keep doing it.

New cap, new rotor, leads and connections to plugs like I describe and all should be good.

If it is the ht side that is giving problems. If it is points, condensor or coil I can't say, but believe me, the ht side is often overlooked and I had lots of problems all around the ht side. (ht = high tension).

I had lucas, helmet and crab all with these problems. solid leads, no resistance caps and tight plug gaps sorted it out. But it had to be backed up by replacing the compromised rotors and caps.

Mart.

[FlatheadTed]

Yes I could help ,

[Karl]

I found you -you little #%#%# !

Update form my last post I drained the tank and found some thin membranous stuff in it ? POR 15 tank lining or perhaps vanish -I fiqured it might be blocking the intake in the tank causing intermittent starvation-Before pulling the tank and cleaning it -I by-passed the tank and fuel line and applied a line direct to the fuel pump and ran it into a can of clean gas inside the car - Still missed !

My neighbour has always suspected the spark plug leads so i changed those out yesterday and went for a test run today. Still missing and fact missed to the point were it wouldn't keep going . Luckily occurred on a straight stretch of road so before it died i pushed the clutch in and turned the ignition off and coasted into the side of the road. (I wasn't worried about steering lock as I was going slow and didn't need to turn the wheel ) . Looking under the hood and there you are an air fluid level in the fuel pump bowl. Its sucking air at the fuel pump bowl -Just as one of the early posters suggested on here !- So next weekends job is to fix that -One of the few non original parts i have on my car is the fuel pump with a bowl - Given the varnish in the gas I might stick with it for now -Karl

[petehoovie]

Yup! - Posts #11 and #22....

[Tinker]

Glad you figured it out! Napa sells sheets of cork.