The Stovebolt Site Forums The Shop Area The Electrical Bay Starting conundrum

Ok, here's one for you guys...

I switched to Petronix (hated it...didn't work work a crap), and decided to put traditional points and condenser back in (which is what used to work so well). However, I can't get it started, and I have this nagging feeling that I'm missing/forgetting something.

I have new plugs in, properly gapped. I've tried two coils, two sets of points, two condensers (still no starting).


I have the distributor wire hooked up to (-) side of coil, ignition to (+) side of coil, all of the plug wires are new, point is gapped properly. I can't time it yet because I can't get it started; however, I think it should still start, just have to be timed properly. There's gas going to the carb, blew all passages out in carb; am getting spark to plugs, even put new dist. cap on. Still; nothing. I have NO idea what to try next. Any suggestion? Thanks

is is possible that the firing order is wrong...or the cap is 180' out.....1-5-3-6-2-4, remember that the crank turns twice to 1 rev
of the cam, maybe timed on #6 rather than #1.....

Did you set the timing "statically"? If you have, ignore the following.

Turn the engine until the #1 cylinder is on the compression stroke. You can find this by checking the valves or by pulling a plug and putting your finger over the plug hole while you (or someone else) moves the crank back and forth near TDC/UDC (rotate the harmonic balancer or the flywheel). Once I find this, I line up the pointer on the clutch-housing to the ball/mark (bb?) in the flywheel.

Then, make sure that the #1 ignition wire is where the rotor is pointing. Check sequence: 1-5-3-6-2-4

Yeah, you boys are on to something, and I wonder if that's why the petronix didn't work well. I ve always had plug wire sequence correct, but think the rotar isn't pointing at #1 spark plug when at TDC. I would just pop the dist. cap on, make sure plugs were in right order, then started it and timed with a timing gun. So, again, how do I get TDC without having to pull off valve covers? I didn't understand exactly from previous post how to do it. Thanks again guys.

Hy Starsfan, do you have a Ballast resistor in your setup? Have you checked for voltage at the coil with a test light, use the housing of the distributor as ground. If the light does not light, then use a different source for ground, if the light lights now then your distributor housing/point plate is not grounded, if the light still does not light then you have a power problem. Use a test light with a good size bulb, I like to use an 1156 bulb for these tests because it actually requires some current to make it light. Don't use a digital meter, they will react to milliamps of current, which is not enough to make a lightbulb light. If your light does not light, your problem could be anywhere from your ignition switch to the connection at the coil, I've seen wires with broken conductors immediately outside of a terminal cause a lot of electrical gremlins. You could try hot wiring the coil directly to the battery to see if that helps. Maybe whatever this problem is is what caused your Pertronix setup to perform so poorly.

I do have a ballast resistor, but I'll try your suggestions. Thanks.

I did something different this time, and just remembered it. This time I took out the distributor to replace the bolt that tightens distributor shaft (for timing purposes) I bet I dropped the distributor back in (as somebody suggested above) 180 degrees off. I'll try again tomorrow and let you guys know how it turns out. Thanks again.

One more question. Is another wayto find TDC is to hand crank engine until BB lines up with pointer?

You have a 50% chance of that technique working. The crankshaft rotates twice for for each full cycle of the engine. That is why you have to check to see if you are on the compression stroke.

If you want to try yor luck, rotate the wires in the cap so that #1 and #6 are interchanged, along with the others. This will change the timing by 180 deg.

Just pull the #1 spark plug and put your thumb over the hole. Have someone tap the starter repeatedly until you feel compression pressure pop your thumb out of the plug hole. If the distributor is timed right, the rotor should be very near the #1 plug tower on the cap. If it's pointing toward #6, you've got the dizzy in 180 degrees off. Either rearrange the plug wires, or reposition the distributor.
Jerry

Thanks jerry

I had the truck for years, but have never had this level of stump-ness.

The rotor is pointing at 1 spark plug at TDC; all plug wires are in right order. I've check current, and have it all the way to ignition. My only question there is, "I only get 6 volts at the coil side of ballast resistor, the other side going to ignition is 12 volt.

Anyway, I've tried two coils, two sets of points, two rotors, and two condenser. I have no idea what could be wrong. plugs and points all gapped correctly. Have new dist. cap also. I'm getting gas to carb, blown out all of those passages, as well. I'm at a total loss. Man do I wish I never would have put in that petronix...that was the beginning of all of my problems.

sounds like you may be missing the starter to coil resistor bypass wire, try like 3B said, put a wire direct from the battery to the coil + while trying to start

Bill

so you mean to bypass the bsllast resistor, which would effectivey take the wire straight from ignition to + side of coil?

question: what is resistor bypass wire? thanks

yes - depending on your particular setup, the resistor bypass will come from the starter or ign sw and give a full voltage route to the coil only when starting, then when you let off the starter, the voltage is applied to the resistor for the run condition - if that setup is missing [maybe changed when the pertronix was installed] then you may not be getting anything other than that weak 6V to the coil when cranking, could easily cause spark to be too weak to fire

Bill

The ballast resistor will drop the voltage to the coil primary whenever the points are closed and the ignition switch is turned on. When the points are open, you'll see full battery voltage on both sides of the resistor. It's normal to see about 9 volts at the coil with the engine running, down from about 13.5-14 V. at the battery terminals. 6 volts at the coil with the engine not running, points closed is about right.

What type of starter setup do you have, key start or stomper? The 12 volt stomp starter switch will have a small terminal on the side that needs a wire attached from it to the downstream side of the resistor, or the coil (+) terminal. That wire provides full battery voltage to the coil during cranking, bypassing the resistor. If the voltage to the resistor drops during cranking because of the extra load of the starter, voltage to the coil might not be sufficient to provide a good spark without the bypass.

The solenoid-operated starter for the key start system will have a small terminal on the solenoid cover labeled "I" (ignition). This terminal does the same thing as the bypass terminal on the stomp switch, providing full battery voltage to the coil during cranking.
Jerry

Edit: Is it possible that the wire from the coil to the distributor is getting grounded to the distributor housing? Turn the engine until the points are open, or just place a piece of paper or a business card between the points. The voltage at the (-) terminal of the coil, or the connector on the side of the distributor should go to battery voltage. If it stays near zero, you've got a grounded primary wire in the distributor, doing the same thing as the points staying closed all the time- - - -no spark.
Jerry

Hotrod, I've got a stomp starter. I'll try your recommendations in regards to determining the grounded distributor wire issue. Question: How would the (-) side of the coil get voltage if the points are open? I thought they would only get voltage if the points are closed. When all is said and done, I think this'll be a good educational experience; I feel this (coil, condenser, points, resistor, et al.) is definitely my weak point when understanding the truck; I've put in new rear end, transmissio...no problem; but I'm no eletrical engineer.

Update: I do have current when I test the +side of coil, then ground it to the distributor. Again, a vexing issue. I know it's one of those things that, when it's fixed/discovered, will be a big 'Man, I should have thought of that' moment--but at this point, it's really got me stumped.

As well, I bypassed the resistor, taking 12 volts from switch straight to (+) side of coil...to no avail.

Just so I understand, the wire going from side of distributor is supposed to go directly to (-) of coil, correct? Also, I have wire going to (-) side of coil to tachometer...but I've had that for about 6 years, and it's never caused a problem before.

Hy starsfan, just to eliminate one more thing, remove the tach wire until we find the problem. Check the fixed point to see if it's grounded, there should be a wire between the point plate and the distributor housing, this is required because the point mounting plate moves with the advance mechanism. With the points open and the ignition on, you should have current right down to the movable point. Hope that helps.

Thanks, 3B, I'll unhook tach wire for now (I'll do it this weekend, unfortunately I'm out of town on biz until then).

But regarding the point mounting plate, I'm not sure I understand. The point mounting plate has the bolt that goes through dist. and inside dist. cap that the points and condenser are hooked to; on the outside of the dist., of course, is the "rest" of that bolt onto which the wire is connected that leads to the (-) side of the coil. Is there another wire connecting the point mounting plate to the distribuotr housing? Also, I don't understand the part about the point mounting plate moving with the advance mechanism. I thought the entire distributor moved with the advance mechanism.

But, back to the aforementioned wire, there's one connecting the point mounting plate to the distributor? The only thing I have connected to the distributor is the (-) wire to the coil, and, within the distributor, the condenser and points to that bolt which extends through the distributor housing (which, again, is connected to the (-) side of the coil. Thanks again.

P.S. I know this issue has comething to do with the way I put the distribut back together after pulling out the Petronix unit. Again, prior to putting it in, the truck purred.

Hy starsfan, I'll go dig out a six cylinder distributer just to check everything out, but I think you're correct about the whole dist. turning, rather than just the point plate, I guess I've been working on V8s too much. Anyway the electrical checks are still applicable.

So am I missing another wire at distributor? I've got one going to (-) side of coil, and the points and condenser connecting to bolt in dist. cap. Thanks

Hy starsfan, I'm not sure at this point if anything is "missing", but I'll look into it today.

The entire distributor moves for vacuum advance on the stovebolt engines. Below the breaker plate, there is a set of centrifugal weights, so the cam assembly moves to advance the spark from engine speed changes just like a V-8. It's possible for the stud that goes through the housing to get grounded, creating the same effect as the points being closed all the time- - - -no spark. That's why it's important to get the points open, and then check for voltage at the terminal on the outside of the distributor housing. With the points open, voltage will go all the way to the insulated point so full battery voltage will be measured at all connections from the battery to the insulated point. There will be NO voltage differences anywhere in the system until current starts to flow when the points close. It's like pressure in a water hose being the same all the way to the nozzle until water starts to flow. No flow- - - - -no pressure drop.
Jerry

Thanks, Jerry. But what's the insulated point?

Hy starsfan, the "insulated point" is the moveable point, the fixed point is grounded to the breaker plate, hope that helps.

Perfect. Thanks.

Getting back to the distributor being grounded issue, what's holding the distributor in place? The only thing I see is the bracket (for lack of a better term) that the distributor slides through, which is connected to the vacuum advance. It's the bracket that you loosen, then tighten, when you're timing the engine. I guess ultimately the question is: how does the distributor get grounded properly (other than having to connect another grounding source, like a wire from it to, say, the engine block)? Thanks

It's a bad design, with several possible points of contact, the housing against the block, the gear drive between the camshaft and the shaft, and a couple of other places, but nothing that's really a good ground. Adding a very flexible ground wire that doesn't rely on a moving connection is the best solution to the problem, but if you want an original-looking restoration, it's necessary to depend on an unreliable ground for the points.
Jerry

Thanks; yeah, the added ground wire definitely sounds like the way to go.

If you've got a set of test leads from a discarded voltmeter, etc., a piece of one of them will be flexible enough to handle the constant motion of the distributor housing without breaking the strands of the wire. Regular primary wire won't last long before the strands start breaking up from metal fatigue. Be sure and solder the connections at the terminal ends for the best conduction.
Jerry

When I test for voltage at the (-) side of the coil, I get no voltage. I get 12 volts to switch side of ballast resistor, 6 volt on other side of resistor, but no voltage at (-) side of the coil. The wire from the ballast resistor DOES go to the (+) side of the coil, right? I've tried a couple of coils, in the even one is bad.

Also, I connected a ground wire from the clip screw that holds dist. cap on top of distributor, then connected it to the engine block.

But, again, I have no voltage to the points. I don't know what is going on. In all of my years of owning, and working regularly on, the truck, I've never, ever had a stumper like this one.

P.S. Does the coil need to be plugged into top of dist cap to get the voltage to (-) side of coil? Mine wasn't. Is that why I didn't get voltage to (-) side of coil?

Be sure the points are open when you test for voltage. If they are, and you still get no voltage on the (-) side of the coil, you've got an open-circuited primary winding in the coil, or the wire from the coil to the distributor is grounded somewhere.

Take the distributor cap off, rotate the crankshaft until the points open, and test for voltage at the distributor side of the coil. No voltage- - - -take the wire off the side of the distributor and check it for voltage again with the wire connected to nothing. There should be voltage there now. I believe the connector that goes through the distributor housing is grounded, giving the same result as the points being closed all the time. It happens pretty often.
Jerry

I'll give it a shot and let you know. Thanks

One more thing, though. If I have no wire hooked up to the negative side of the coil, I should get 6 volts at the (-) post of the coil...again, with no wire attached to the coil on the (-) side. Of course, the wire from ignition will be hooked up to the (+) side of the coil, right?

Nope, you will get the full 12 volts, because no current is flowing. Unless the voltage has somewhere to go (ground), the full applied voltage goes all the way to the end of the circuit with no drop. Resistors only drop voltage when current is flowing through them. (Yep, I had a terrible time understanding that principle back about 40 years ago in Air Force electronics school! Just about everybody does!)
Jerry

Huh, then I wonder if something is wrong with my resistor, because I measure 12 volts at the switch side of resistor, and 6 volts at the distributor side of resistor (and, of course, the engine isn't running). So you're telling me there should be 12 volts all the way to the (-) side of the coil? Thanks.

OK, one more time- - - - -IF the current is flowing (the (-) terminal of the coil is grounded) you'll see 12 volts at the upstream side of the resistor, 6 volts or a little more at the (+) coil terminal, and 0 volts at the (-) coil terminal (ground). IF THE POINTS ARE OPEN AT THAT TIME, YOU'VE GOT A BAD DISTRIBUTOR CONNECTOR! With the points open, take the wire off the distributor and see if the voltage at the coil (-) terminal changes. Please, please, please- - - - - -take the wire off of the side of the distributor! The short is right there where the connector goes through the distributor housing! I've seen this problem dozens of times!
Jerry