Trouble shooting help - '46 Deluxe
 

Here's the basics:
'46 Deluxe - bone stock 6V 239 V8 (completely rebuilt 6500 miles / 8 years ago)
2 year old battery with clean connections
Grounds to frame and block with 00 cable
Distributor rebuilt by Third Gen 2 years ago - plug and coil wires replaced
Wiring replaced during restoration to OE spec
New fuel tank and lines during full resto in 2017/18
New radiator / water pumps in 2017 - no issues with heat or overheating

Background
Typically a ready starter after a few seconds of cranking - hot or cold

The Issue
Recently - like just this week - warm restarts are suddenly a problem.
Cranks as it should but doesn't fire. Fuel flow is good.

On the first instance, I used a jump box (after a few minutes of cranking w/o fire) and it started immediately. It has also started instantly if roll starting by popping the clutch in gear.

Today, I found that it will also start immediately if the ignition switch is moved to 'ON' while the starter is engaged.

What have I done?
Checked coil wires and swapped out the coil for a NOS version on hand (no change).
Coil does NOT get warm to the touch when in 'no start' mode
The coil I removed has been sent off to Skip for a rebuild.

Looking for wisdom from those who have been here before. What should I check?

I appreciate any inputs.

Re: Trouble shooting help - '46 Deluxe
 

Maybe it’s flooded? Have a ‘53 that has always been a bear at hot restarts. If I shut it off (when hot) and immediately hit the starter, it starts in half a revolution. If I let it sit for a couple minutes, it’s very hard to start. I have to push the gas pedal down almost all the way and crank it for 8-10 seconds, and then it’ll catch and start. I think I have gas percolating in the bowls (two 94’s), and that’s flooding it and it seems I have to clear that out to get it to start. I’ve blanked off the power valves, have insulators under the carbs, and no improvement. A couple of your scenarios sound to me like you clear out the flooded condition and then it’ll start. Good luck; hot restart problems are definitely a pain. I think with some flatheads, you just have to find a combination of steps that work, and then repeat. I just finished a ‘46 Merc and it starts beautifully under all conditions. Wish I knew what I did right!

Re: Trouble shooting help - '46 Deluxe
 

Thanks for the comments.

This flathead does have a certain procedure, as most do. Doesn't seem to be a flooding issue as it has started immediately without the typical over fueled behavior (smoke and engine sputtering until clear). In addition, this engine doesn't need any choke - ever.

Re: Trouble shooting help - '46 Deluxe
 

Like the coil, sometimes the condenser will work fine when cool and then fail when warm, giving weak spark. Condenser is cheap and easy to swap out, worth a try. When buying a condenser, might want to buy two; they are known to be bad out-of-the-box sometimes. And don't buy a NOS condenser; they will go bad just sitting on a shelf.

Re: Trouble shooting help - '46 Deluxe
 

This caught my attention. Try running a wire that goes from the battery to the distributor side of the coil, bypassing the resistor. If that works, wire up a momentary switch that you can toggle while cranking. For normal running the resistor is in play.

Ignition Switch to Coil Resistor; Black with Red 16
(also found as Red with Blue)
Coil Resistor to Ignition Coil; Red and yellow 16
Ignition Coil to Distributor Points. Black 16

Links for your wiring diagram, https://www.fordbarn.com/forum/showp...44&postcount=5

Re: Trouble shooting help - '46 Deluxe
 

Re: Trouble shooting help - '46 Deluxe
 

"Today, I found that it will also start immediately if the ignition switch is moved to 'ON' while the starter is engaged."
This is a mystery to me. Any electrical gurus want to explain this? Starter is still cranking, still pulling down voltage available to the ignition circuit. Dirty ignition switch making better contact while transitioning from off to on?

Re: Trouble shooting help - '46 Deluxe
 

Thanks for the input.

I failed to mention that this is a 59AB with the rabbit ear distributor - access is not easy, unfortunately. My plan will be to work the resistor angle first, swap out a fresh Skip rebuilt coil next, and go the condenser route if still battling the problem.


Thanks for the input. I'll give this a try and report back

Re: Trouble shooting help - '46 Deluxe
 

Hard to tell why this is true without more data, however it may have to do with the resistor. If the ignition is ON then a start is attempted, it’s possible the current flow heated up the resistor. Under heated conditions the resistor likely has more resistance than a cold resistor. If the engine is cranked and the ignition then flipped to ON, there may be less resistance in the resistor and starting is then more likely. This is a guess but it would make me want to check that resistor. Some of the newer repro resistors aren’t very good. I had a new repro act funny, found a NOS replacement and solved that issue.

Besides checking the condenser (another typical problem), if your running ethanol gas you could be getting bubbles in the carb or the fuel bowl could be boiling under high heat. Had this happen on my ‘39. I put a carb spacer in which helped but switching to non-ethanol fuel solved that problem.

Re: Trouble shooting help - '46 Deluxe
 

Thanks for your comments.

Interesting. I'm running a NOS resistor but it still could be misbehaving.

I've watched the fuel bowl and haven't seen any bubbles or had any vapor lock issues. The weather hasn't been at all warm and the engine temps have been unremarkable.

Re: Trouble shooting help - '46 Deluxe
 

[QUOTE=glennpm;2389411]
Try running a wire that goes from the battery to the DISTRIBUTOR side of the coil, bypassing the resistor.


Is this correct? I would have thought you would run the wire from the battery (non-grounded side) to the ignition switch side of the coil.

Re: Trouble shooting help - '46 Deluxe
 

You need a voltmeter to check this problem out. I would check for voltage at different locations in the ignition system starting at the distributor and working backwards.

Re: Trouble shooting help - '46 Deluxe
 

69a is correct in post #11

As I understood it, this is a warm restart problem. I don't think this is a voltage problem or he would have trouble with cold starts too.

BTW: I have tested five ballast resistors and watched them drop voltage as they get hot. They do increase the voltage drop as they get hot, but by only an additional 0.2 -0.3 volt. Negligable.

Re: Trouble shooting help - '46 Deluxe
 

Have you replaced or rebuilt your ignition switch? Does it feelloose when moving the lever ? It could be worn to the extent that when switched to the on position it doesn’t have the tension to give good contact , but when switching to the on position you’re actually putting a little pressure on the contacts , thereby giving it just enough contact for good continuity? Just a wild guess without my coffee…..
Good luck , Gary

Re: Trouble shooting help - '46 Deluxe
 

[QUOTE=69a;2389450]Running the test wire from the battery to the ignition side would be a way to see if the ignition switch is causing the problem. Running the test wire as I mentioned, would bypass the ignition switch and the resistor. To make a permanent change to bypass the resistor during starts, yes you would run a new wire from the ignition switch, to the distributor side of the resistor..

https://www.fordbarn.com/forum/attac...8&d=1747482702

This change will give you battery voltage for starting and not a reduced voltage for protection of the points.

Glenn

Re: Trouble shooting help - '46 Deluxe
 

Thanks for the reply.

The ignition switch does not have any play and the connection block behind it was replaced with a NOS piece. I will inspect and check all of the contact points based on your comments.

Re: Trouble shooting help - '46 Deluxe
 

Suggest you place a voltmeter on the wire from the ignition switch to the resistor, see if the voltage dips badly. when the start fails and try it again when the start works well. The starter pulls max amps when it first starts once running the amps are much lower. Your battery should be checked for CCA.

Re: Trouble shooting help - '46 Deluxe
 

What range of voltage should I expect when starting?

Re: Trouble shooting help - '46 Deluxe
 

Could be a dirty ignition switch. The contacts inside those switches get dirty and burned over time causing a high resistance to the ignition. Try placing a jumper wire from the Batt terminal to the Coil terminal on the back of the switch. I’ve had to remove and clean the switch in my 40 a couple times for these very symptoms.

Re: Trouble shooting help - '46 Deluxe
 

Good to know. Thanks!

Re: Trouble shooting help - '46 Deluxe
 

Ken/Alabama has a good point about the ign. sw.. I had to do the one for my '46, as I was getting intermittent ignition problems. If your has not been apart, you will need to drill or grind away the "crimps" (look closely at the bolting flange) at the mounting holes to split the case. Take note of the position to the sliding piece (see arrow on pic) when you reassemble, because the slot in it has to align with the pin on the switch lever. After you have it cleaned, put a short piece of tape from the back plate to each side of the case to hold the sw. together until it is bolted in place. Put a bit of Vaseline on the sw. contacts before assembling.
Make sure the lever pin is in the sw. plate before tightening the bolts, or you will damage the switch.

Re: Trouble shooting help - '46 Deluxe
 

https://www.fordbarn.com/forum/attac...3&d=1747492935

https://www.fordbarn.com/forum/attac...4&d=1747492935

https://www.fordbarn.com/forum/attac...5&d=1747492935

Re: Trouble shooting help - '46 Deluxe
 

Switches can be bad. My car came to me with a full 1.0 volt drop thru the switch.

But then why does his car start OK when cold?

Re: Trouble shooting help - '46 Deluxe
 

It is the cold v warm restarts that is most perplexing.

Re: Trouble shooting help - '46 Deluxe
 

Quick test . When cranking with switch in on position, put a little pressure pushing in on the switch. If it starts you found the answer . Easier than getting under the dash .

Re: Trouble shooting help - '46 Deluxe
 

all solutions, IMO, must include address the "cold start success" vs "warm start failure" issue.

i would be thinking a short might be manifesting itself somewhere in the ignition system when wire resistances inevitably increase along with engine and engine bay temps.

Re: Trouble shooting help - '46 Deluxe
 

Any update FortyNiner?

Re: Trouble shooting help - '46 Deluxe
 

heat will increase resistance in just about any electrical circuit.

Re: Trouble shooting help - '46 Deluxe
 

After posting, my flathead time was suddenly interrupted with some family matters. Hope to return to tending the '46 soon.

Re: Trouble shooting help - '46 Deluxe
 

So, what happened...

Thanks to all who commented and contributed to my initial post. The benefit of experience is multiplied when shared.

After installing a freshly rebuilt coil from Skip's House of Magic, things seem to be all better. The weather here as been on the cool side, but restarts have returned to being nearly immediate. In addition, the cold start seems a bit more energenic (not at all a subjective assessment).

The 'why did that happen' element of this business with moving the ignition switch while cranking is going to get tucked away in the Dunno File - along with other mysteries of the universe. Such ponderings require mental lubrication best left for smarter folk.

The '46 will get a complete workout during the weeks ahead and should be up to the task.

Thanks again, Barners.

Re: Trouble shooting help - '46 Deluxe
 

Thanks for letting us know the end of the story. The classic failing coil; works OK when cool, starts failing when warm.

Original post said: "swapped out the coil for a NOS version on hand (no change)." Often NOS parts are actually used/bad parts removed from a car decades ago.

Re: Trouble shooting help - '46 Deluxe
 

Fair enough on the NOS.

When the Little Dearborn shop in Minnesota was selling out, I bought several lots. Included in the randomly organized parts grab-bags were supposedly NOS items. In the case of Little Dearborn, NOS was shorhand for No Organized System as broken, used, and rusty were unused, but accurate, descriptions.

Re: Trouble shooting help - '46 Deluxe
 

today i discovered why my car (1941 Ford Super Deluxe) would start only when cold. if it had been running for about 5-10 minutes or more and then shutdown, it would not start again until it cooled down a bit, and depending on a number of factors, that might take the better part of two hours.

anyway, the problem was a failing or failed condenser. neighborhood NAPA had one in stock for my diver's helmet distributor and coil!

Re: Trouble shooting help - '46 Deluxe
 

Thanks for the update. Too many here don't

I'm interested in what the primary coil resistances are for thee one you removed and the new one too. You can do this by measuring across the two terminal posts.

Thanks

Re: Trouble shooting help - '46 Deluxe
 

For better or worse, the misbehaving coil was one already sent off to Skip and has been rebuilt. So, no can check the before condition.