31 Roadster - Won't Restart / No Spark

[Coach Mike]

I drove my 31 Roadster to a family house for about 15-minutes and ran fine. I shut it off and it sat for about an hour. When I got back in the restart was hard and stalled out. I've got fuel and air but no spark. I think that there may have been a short on an exposed wire. It happened in the past too and couldn't find the issue but after sitting for a few days I got spark and it started / ran fine.

Help!

[RawhideKid]

I think the first thing I would check is the wire between the distributor top plate and bottom plate, then maybe turn the key on and see if the ammeter wiggles any.

IF you have a battery cut-out switch, wiggle that, or a fuse, wiggle/change that.

Corrosion is not your electrical friend. Check for any of that.

You didn't say if it is stock 6v Pos ground, or something else. A bit more info could also help.

My wooden nickle worth.

[Jacksonlll]

First loosen the gas cap and listen for a hiss.

[Patrick L.]

So if you're sure the problem is electrical then just start at the points and work back until the problem is found. It shouldn't take too long.
Look for 6v at the movable point arm when its open [and 0v when points are closed]. Keep working back thru the system/circuit looking for the open circuit or short. The lead between upper and lower plate can be a problem, so can the distributor primary lead from the coil as can the ignition switch. There are a number of places to look but the system is simple and work each connection back thru the circuit. A wiring diagram helps and maybe someone will post one.

[1955cj5]

Here's one....

[eagle]

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A classic example of: if it fixes itself, IT AIN'T FIXED.

[Coach Mike]

Thanks for the good info. It is still a 6v posative ground. The last time this happened I noticed that there was no movement on the ammeter and no spark. A few days later I went out to check spark and it fired right up. Would an exposed wire short out the system causing no spark and then a few days later be OK? I found that exposed wire coming off the generator rubbing on some metal

[Jerry in Shasta]

Also consider HEAT. Is the condenser failing? Is the coil failing under the heat and load?

These are two things I always carry as spares, most notably the condenser

Just my W.A.G. at the problem
JB

[Patrick L.]

Originally Posted by Coach Mike

Thanks for the good info. It is still a 6v posative ground. The last time this happened I noticed that there was no movement on the ammeter and no spark. A few days later I went out to check spark and it fired right up. Would an exposed wire short out the system causing no spark and then a few days later be OK? I found that exposed wire coming off the generator rubbing on some metal

Of course, problems can be intermittent. Especially considering how much the wires are moved within this system. The insulation fails in the primary leads that can cause an unwanted ground/short or the wires can fail from years of use causing an intermittent open. A condenser or coil can fail especially when warm, but, that doesn't happen too often. Your problem will most likely be wiring/ connection or even dirty points contact.

[BILL WILLIAMSON]

Don't forget to grab your trusty old TEST LIGHT & poke around, MANY problems can be located with them. Make SURE the bulb in the test light is GOOD!---LOL
Once at work, we put a FLASHING bulb in Joes' test light!!! They're sometimes used as a WARNING light, on Old Tractors.
Bill W.

[JonC]

I think Jerry in ... is right, I bet coil, Sometimes heat soak raises temps higher after you turn it off. HOPE YOU FIND IT.

[Coach Mike]

I did some testing according to Patrick and the manual and everything has 6v until I got to the points. I put paper to hold points open and couldn't find voltage. Condenser?? The condenser wire looked good but couldn't get to lower plate wire that RawHide suggested. I also double checked the ignition switch and that toned out fine.
Jon C - I checked both sides of the coil and it was at 6v

[Patrick L.]

So if I understand correctly you checked for power at the switch and it seems fine ? But, nothing was checked from/between the switch to the points ? And, there is no power at the open point arm ?

You need to remove the upper plate. Generally the problem can be found in the jumper wire from the upper to lower plate or its connection. This is a special very fine strand wire which may have been replaced with an improper stiff wire that has broken or worn thru the insulation. Also I've seen condenser connections come loose [ generally thats just the opposite in that they are hard to remove the screw.]. Another trouble spot is the primary cable from switch to the distributor which is generally armored. The inside insulation will break down over the decades causing a ground/short or the wire can break causing an intermittent open. Any of these can be fixed quite quickly if the right parts are in hand. While its apart for peace of mind you may want to install one of the ' burn-out' proof condensers especially if other parts need to be ordered. There were some poor quality ones being sold for awhile and its possible you may have one. Another possibility is a bad coil but it doesn't sound like your problem. I think You've located the problem as talked about earlier in the paragraph. But, an oil filled coil does not like to tipped upside down and can cause an intermittent problem.

[Coach Mike]

I have checked everything between the switch and the points and everything had 6v until I got to the points. I'm leery about taking the top plate off because I'm assuming I'll have to re-time it? I have a timing wrench on order. Is that accurate about having to re-time it if I take off the top plate?

[RawhideKid]

If you remove the points plate, unless you adjust the points, you will NOT need to retime it. Remove the rod from the steering column, twist the plate counter clockwise and hold your hand over the plate because the spring below the plate will want to push it up at you.

Then all you need to do is check the wire for breakage or a bare spot to rub against the inner distributor housing. While you have the plate up, check to be sure the housing around the armored cable is not touching the inner plate, meaning it is screwed in too far.

[BILL WILLIAMSON]

Many folks are scared to remove the upper plate, to check the pig tail wire. It's NOT complicated, just take your time.
Everyone should have an old junk distributor, just to practice on. Just take it apart & put it together & see if you have any PARTS left over--LOL
Bill Tinkerer

[RawhideKid]

HAHAHA!! Thanks Bill, a real confidence builder!

Keep up the good work.

[Big hammer]

Originally Posted by RawhideKid

If you remove the points plate, unless you adjust the points, you will NOT need to retime it. Remove the rod from the steering column, twist the plate counter clockwise and hold your hand over the plate because the spring below the plate will want to push it up at you.

Then all you need to do is check the wire for breakage or a bare spot to rub against the inner distributor housing. While you have the plate up, check to be sure the housing around the armored cable is not touching the inner plate, meaning it is screwed in too far.

My cam will not let me remove the plate without removing the cam :-(
Next time I may open up the center hole.

[Bob C]

Originally Posted by Big hammer

My cam will not let me remove the plate without removing the cam :-(
Next time I may open up the center hole.

You don't want to do that because your point gap will not be consistent.
You need to peen it like Marco's picture if it is loose.

Bob

[RawhideKid]

Originally Posted by Bob C

You don't want to do that because your point gap will not be consistent.
You need to peen it like Marco's picture if it is loose.

Bob

Right Bob.

Sorry, I forgot all about needing to remove the cam before removing the upper plate. Forgive me, my bad.

So, why not try this, put the crank handle in, using the rotor to get the line up of the #1 TDC and turn the pin around, drop it into the cam gear indent and remove the point cam then. You will only need to use the test light to set the cam back in place when you finish. It really isn't brain surgery to set the ignition timing on these motors, just need the test light.

More spinning of that wooden nickle.