Fried PerTronix? Need sanity check

[Scout Hokie]

Ok so hopefully I've done my homework but as they aren't giving pertronix units away for free, I'd really like a sanity check from you guys. I've got a 1974 Scout II with a 345. As I received it, it does not have a gold box installed. The po did some very inventive wiring so I've gutted it all and installed the ez wire 14 circuit kit. Based on what I've read, the distributor looks to have been upgraded to the pertronix ignitor and my best guess is that its a Holley with curved breaker points (included a photo). The cap has female plugs on top and half moon shaped contacts beneath. They've installed an accel 'super stock' yellow coil. On the (+) coil terminal there are 2 wires, 12v b+ switched ignition and the red wire from the distributor/pertronix. On the (-) coil terminal there are 2 wires, the black wire from the pertronix and the tachometer signal to an autometer gauge. I've disconnected the condensers. So here's where the trouble starts....

I had to remove the intake manifold to replace the gaskets and thus, the ignition coil. Prior to this job, the truck would start and run without issue. I re-installed the intake manifold and went on working on a couple of other odds and ends. I had installed a new radio so I had the key in the on position to get some tunes but since the ez wire kit has the coil toggle switch on the fuse panel, I religiously kept it in the off position in these situations. Well maybe I had a brain fart or hit the switch on my way out of the truck but after messing around for about an hour I went to start the truck and nada. Would turn over just fine but no fire. I stick my head over the carb and its getting fuel, no problem. So I go through the steps. Coil has 1.5 ohm impedance. Disconnect the coil feed to the distributor cap, turn the truck over and I get spark from the coil. Removed a spark plug which is a champion plug unfortunately but its brand new so no fouling or carbon build up. Plug it up to a distributor feed and turned the car over. No spark. Tried it with 2 different spark plugs, no spark.

Also should mention that once I tried to turn the truck over and then noticed that the coil switch had been left on for about an hour, I noticed that the coil was quite hot to the touch. Inspection of the pertronix itself does not appear to be damaged due to excessive heat but I know that doesn't mean it hasn't been damaged.

Sorry for the long winded email but figured that anyone willing to help would like to have the detail. I did check battery power prior to my exercise, had 12.4-12.5 volts throughout (re-charged it after the radio drained it a bit). My assumption is that the pertronix got cooked. My other assumption is that I need the pertronix #1481 kit. Also as a sanity check, I've read that my setup does not need a ballast resistor since it has been converted to pertronix, would just like a vote of confidence that the ignition b+ to the coil is a-ok.

Thanks for all the help! Can't wait to get this Scout on the road.

 

[Scoutboy74]

Welcome to the forum. My thoughts on your issue are as follows: if your p-tron module is the first generation variety, and if it was subjected to an interval of continuous current input while the engine was stopped, then there is a good chance that it is fried. Your ability to find spark from the coil, but not at several random plugs is pretty telling. A p-tron module in this engine application does not require additional ballast resistance beyond what is provided by a coil as long as the coil has a primary resistance of approximately 1.5 ohms. I'm no fan of the champion plugs either, but there are others on this board who swear by them and who's opinion I respect, so that choice really comes down to personal preference in the final frame. I've personally witnessed an ihc 304 start and run, although very poorly, with no fewer than 4 dead spark plugs installed. I can't remember the brand, but I know they weren't bosch platinum, autolite 85', or ngk...all of which have delivered consistently great results in my binder engines, in spite of the occasional bout of raw fuel flooding.
How do you avoid this in the future? 1. Buck up for a p-tron II or iii with internal overload protection circuitry. 2. Use the acc position on your key tumbler for powering your tunes in engine stopped situations. That's what its there for. Its the best fail safe feature your vehicle has for protecting your sensitive electronic ignition components from human-caused failure.

 

[Scout Hokie]

Scoutboy - really appreciate the input, actually most of the 'homework' that I did on the subject was via a thread on here in which you provided quite a bit of guidance for troubleshooting, so thanks for that too! Just to ensure I chose the correct pertronix, was my guess that the #1481 being my huckleberry correct? Definitely a great suggestion on the ignition switch too, I really thought it was strange that the radio only came on in the on position. That would help keep me from worrying about the coil toggle on the fuse panel.

 

[Scoutboy74]

You're welcome. The 1481 would be an identical replacement of what you have now. With nazi-like, anal retentive effort applied towards ensuring that the unit is not energized while the engine is stopped, it should deliver years of reliable service. Now, if you simply add a '9' to the front of the '1481', you have the product number for the more guuder p-tron II version that is made to fit the Holley curved point distributor. Either module is available for purchase here via the IHPA web store. Always nice to support the vendor who supports this forum when possible. the p-tron II version is $40 more on the web store.
You currently have the power source to your myoozik makin' box connected to a switched 'on' source. If you relocate that power feed to a source that is hot in the 'acc' position, it will also be hot when the key is 'on' with the motor consuming defenseless hydrocarbons.

 

[Scoutboy74]

Hey, before you make your purchase, go ahead and remove your current module and snap a pic of the internal distributor housing. I just want to make sure that your distributor is a points version and not the Holley electronic aka gold box. What I can't tell conclusively from your pic is if there is a breaker cam or a reluctor wheel under the black center spool. Don't fret if your plastic dust cover comes out in chunks. It looks brittle and the integrity has already been compromised. You can discard it if you'd like. Another thing I noticed is that at least in the angle of the pic, it looks like your vacuum advance canister is oriented nearly all the way towards the passenger side cylinder bank. It May be that your timing is a bit retarded. Now that has nothing to do with you not getting any fire at the spark plugs. I'm just saying that when you get it running again, it wouldn't hurt to throw a timing light on the situation to see where your timing is set. If its around zero degrees, you could easily advance the timing 8, 10, maybe even 12 degrees to put a little more pep in the ol' girl's step. First order of business is to get it running again. You can fine tune later on.

 

[Scout Hokie]

Fantastic, all great recommendations. I do believe I May have had a little collision with the distributor vacuum advance when I was lowering the oh so lightweight intake manifold into place. Nothing drastic but I noticed it did move a bit so for sure, need to check timing after I get this sorted.

Speaking of getting this sorted, the plot thickens haha. Yesterday when I tried everything, the battery was at around 12.2 volts so I decided to really let it charge and try testing it again. Had the battery at just over 13 volts and guess what, I'm seeing sparks at the spark plug! However, they seem very weak. With my wife as my assistant, I took some readings at the coil while she bumped the starter. With the coil on, battery at 13v, I'm reading 10 - 10.5 volts when reading across the coil + and -. When she bumps the starter, I'm getting really low readings, down to the area of 5-6 volts. I'm thinking I'm not getting enough juice to the pertronix. Last night, it must have been just not enough juice for me to even see the spark at the plug. So, does the 10-10.5 volt reading at the coil indicate that I have a drain somewhere? Or is that ok but is the coil toast and only giving me the low output? All I know is it ain't right, haha.

Also, your mention of the acc issue made the light bulb go on over my head and thinking, of course it should be that way, like I mentioned I rewired every inch of the truck with the ez wire kit so I determined I must have wired the ignition switch on the column incorrectly. I'm finding conflicting info in the ez wire manual vs. The Scout manual. I've tried them both and tested them by reading voltage at the power feed to the radio, not the radio constant. I've attached crude sketches of the wiring that I've tried, labeled whether its the ez instructions or my own research. Neither work. In both cases, I only get power to the radio when the key is in the 'on' position. Next question is, do I have a bad ignition switch?? When I bought the truck, the po had removed the plastic cover around the column and I saw all the makings of an electrical scavenger hunt going on so I'm thinking its possible that it was doa when I bought it. Thoughts? Oh and I have that dashed line on the 'research' sketch to indicate that those two points are connected but forgot to add it to the ez wire one, just my error but it appears from what I've seen and read, that those two posts are connected anyway so doesn't matter which the +12v is supplied to.

Also, I'll take a pic of the innards of the distributor as well, even though it appears the pertronix might be ok, I'd like the info for the future since I'm bending your ear!

 

[Scout Hokie]

Update: realized I was making a mistake, I shouldn't have been taking voltage readings from the coil + and coil - but should've been coil + and ground. So, made more readings. Battery was at 13.1 v. With ignition at on position, voltage at the coil was dead on 12 v. While bumping the starter, the readings were at 9 - 9.5 v.

 

[Scoutboy74]

Yes!!!! I was just in the process of scolding you about that, but now I don't have to. The only time you need to probe across the coil terminals is when you are measuring the primary resistance with your meter set to measure resistance in ohms. All wires should be removed from the coil terminals for that test also.
How far do you have the spark plug electrode away from a metal surface when you check for spark? You should allow an air gap of roughly 3/8ths of an inch. If your spark won't jump that gap to ground, then it won't be strong enough to ignite the air/fuel mixture.
Your fuse block should have a circuit dedicated and labeled for your radio power feed. The sii ignition switch is the uber-common delco/remy design that was utilized in elevendeebillion GM vehicles during the 70's and 80's and utilizes a molded plug with female blade terminals that only fits one way onto the corresponding male blade terminals on the switch. Its possible that the switch bracket is out of adjustment just enough to prevent your plunger rod from fully engaging the switch contacts when you rotate the tumbler to the acc position. This would also throw off your other switch detent positions in a similar fashion. The first thing I would want to verify with a simple 12v incandescent test probe is the presence of current from any of the wires exiting your ignition switch when in the acc position. Confirm that any hot wires you find in acc go cold when the switch is turned off. That would be your accessory feed to the fuse block. Clear as mud?

 

[Scout Hokie]

Well I actually was grounding the spark plug itself so I was just looking for arcs between the electrode and the tip itself. Should I remove me fancy alligator clip grounding system?

Now that you mention it, the switch bracket does look like its been mangled a bit! Someone appears to have had plenty of coffee one morning and went to slamming a steering column in place. I had a feeling that the Scout switch was the standard GM switch so I'll roll with that. Not only that, but it lines up with the schematics in the manual.

 

[Scoutboy74]

Yeah, try it again without any part of the spark plug actually touching metal and the electrode positioned with a small air gap to ground. That's the same way you want to test your coil high tension wire for spark too. A good spark will shoot the gap. If you find that your iggy switch needs replacing, just know that there are two versions...tilt column and non-tilt column. They appear similar, but they aren't interchangeable. Your switch must match your column design.

 

[Scout Hokie]

Welp, I'm officially con-fuzzed. Didn't take any voltage measurements but I'm sure the battery was at a healthy 13+ v. Laid the plug down on a rubber glove with the electrode about 3/8 of an inch from ground, shut the lights out in the garage and bumped it over. Spark! Seemed to be consistent and rather bright.

So I've got fuel. I've got air. And it appears I've got spark...??????

 

[Scoutboy74]

Well that's great! Button everything back up. You say you think you bumped the distributor enough to rotate it. That means two things. One, the bolt that is supposed to lock the distributor in place is loose. That shouldn't be so. And two, you've retarded your spark timing. Try rotating the distributor in the other direction, just about halfway for now. You May have to loosen the bolt in order to get it to rotate freely by hand. Then be shure to snug it back down. Then turn on the juice and see what shakes loose. If you have air + fuel + adequate spark at anywhere close to the right time, the damn thing has to fire up. That's one of them universal laws of the universe deals, so says the good folks at the department of redundancy department.

 

[Scout Hokie]

Well, the Scout lives again! Buttoned everything back up last night, turned the key and it jumped right to life. Let it run for just a minute and shut it down. Tried starting it again and it wouldn't start. Now I didn't check battery voltage before the first attempt but based on recent testing, it should've been at 13.1 v or so. Went and checked the battery after the failed second attempt and it was at 12.6 v. Why in the world wouldn't this truck start with a battery at 12.6v?

Also, I took more pictures of the dist. Without the dust cover. Not the best pictures in the world but maybe this will confirm the type. I'd like to have that info for a rainy day.

Do you reckon that my coil is nearing the end of its life based on the fact that it doesn't provide enough punch unless the battery is juiced to over 13v?

 

[Scout Hokie]

As a follow up, lets just say for giggles and grins that I decide to go with a new coil to see what happens. I know there is no reason to get a coil that puts out eleventy-billion volts but is there an advantage to getting a coil with lower impedance? Currently I'm at 1.5 ohms, could dropping the impedance on a replacement coil help boost the output to the distributor? I'm a mechanical engineer so I greatly appreciate this lesson in sparks, haha.

 

[Scoutboy74]

well, the Scout lives again! Buttoned everything back up last night, turned the key and it jumped right to life. Let it run for just a minute and shut it down. Tried starting it again and it wouldn't start. Now I didn't check battery voltage before the first attempt but based on recent testing, it should've been at 13.1 v or so. Went and checked the battery after the failed second attempt and it was at 12.6 v. Why in the world wouldn't this truck start with a battery at 12.6v?

well that's sorta cool. At least we know your p-tron didn't fry, which is the most spendy part of this deal. You really shouldn't see a stored surface charge in a battery above 12.8v. Its only common to see a higher number while the alternator is turning. So any surface charge above 12v should be sufficient to fire your ignition provided enough cranking amps are reaching the starter and the voltage drop at the coil is within spec.

Also, I took more pictures of the dist. Without the dust cover. Not the best pictures in the world but maybe this will confirm the type. I'd like to have that info for a rainy day.

I still can't tell from those pics. What's hiding my view is that black (magnetic?) item under the rotor. I've never purchased or installed a p-tron myself, so that's why I don't have the proper nomenclature for that item. Anyway, underneath it, there will either be a breaker cam (for contact points) or a reluctor wheel (for electronic ignition) a breaker cam will have very subtle ridges corresponding with the number of engine cylinders. A reluctor wheel will look sort of like a miniature martial arts throwing star with very pronounced ridges that correspond with the number of engine cylinders.

Do you reckon that my coil is nearing the end of its life based on the fact that it doesn't provide enough punch unless the battery is juiced to over 13v?

the coil May be failing in the wake of being overheated. You should remove the high tension wire from the center of the distributor and air gap test for spark from the coil. Maybe do it several times. You should see a strong, bluish spark every time.

as a follow up, lets just say for giggles and grins that I decide to go with a new coil to see what happens. I know there is no reason to get a coil that puts out eleventy-billion volts but is there an advantage to getting a coil with lower impedance? Currently I'm at 1.5 ohms, could dropping the impedance on a replacement coil help boost the output to the distributor? I'm a mechanical engineer so I greatly appreciate this lesson in sparks, haha.

no, definitely not. 1.5 ohm is ideal for a v8 engine with the p-tron module. That's roughly 8 amps when you divide your volts by your resistance. So a coil with a little higher primary resistance would be safer than one with a lower measurement.

 

[Scout Hokie]

Will do, I'll take another look at the distributor now that I have a better idea of what I'm looking for. I really appreciate you taking the time, there is a wealth of information in this forum on the subject but sometimes there is no substitute for being able to discuss your actual situation and walk through it with someone who has the knowledge. I believe I'm on May way. Hoping I can get it running and put my wife in it so she'll support the purchase of a Holley 0-7448 hahaha. Thanks again, I'm going to go ahead and take the steering column out so I can straighten the ignition switch out and hopefully get that acc 'mode' to kick in.

 

[Scoutboy74]

You're welcome. My knowledge is limited, but growing little by little. I do the best I can with what I've got.
Lowering the column will allow better access to the ig switch, but it isn't necessary. I've never messed with an sii column, which btw is a saginaw column common to a great many GM vehicles of similar vintage...anyway, I can't comment on how easy/difficult that process is. I have replaced and adjusted the ig switch in my Scout without touching the column. I think I removed a couple of my instrument pods so I could look and fiddle through the vacant holes in the dash above the column. Just be sure your battery is disco-ed before you try to handle the pod that houses your ammeter gauge. You don't wanna make sparks and let any precious smoke escape from inside the cabin. I don't think you're wrong to be suspicious of the switch, however, you should first do some electrical probing on the harness between the switch and the fuse block to see which wires light up your test bulb in the various key tumbler positions, primarily acc. If none light up in acc position, then you can see about adjusting or replacing the switch.

 

[Scout Hokie]

Well, installed a new coil and the Scout starts effortlessly! Upon closer examination of the old coil, it appears to be leaking its oil. Probably started when I cooked the sucker but it appears that was the issue. I guess I didn't totally fry it but hurt it enough to degrade its performance. Seems to be in great shape now. Fiddling with the ignition switch, its giving me indications that something just ain't right. I crawled under the steering column and pried the connectors off just enough so that I could attack the connection points with my test light while still leaving everything attached. The rod from the ignition switch moves like I would expect it to but in the acc position, I get no 'fire' to any post except for the ones powered by b+. Switch to run and everything comes to life (I made sure to have the coil on/off toggle switch to 'off' during my testing, hahaha). It appears to me that something is amiss with the spring(s) or something in that acc position. I mean the rod translates past the acc position on its way to run and everything works in the run position and the start position. If it were just out of alignment or something, I would expect that I would get fire to the acc connections at some point in the rod travel, maybe not right at the acc key position but it should become hot somewhere before I hit the run position. Anyway, look out IHPartsAmerica.com, an order is coming your way!

 

[Hondo]

Just my 2 cents worth, always try and go with the ignitor II or iii. Took my truck in for new tires and the moron left the ignition on while they were changing the tires and killed the ignitor I (same guy who told me my truck was "stupid" because he couldn't figure out the e-brake was on). He no longer works there.

 

[Scoutboy74]

well, installed a new coil and the Scout starts effortlessly! Upon closer examination of the old coil, it appears to be leaking its oil. Probably started when I cooked the sucker but it appears that was the issue. I guess I didn't totally fry it but hurt it enough to degrade its performance. Seems to be in great shape now. Fiddling with the ignition switch, its giving me indications that something just ain't right. I crawled under the steering column and pried the connectors off just enough so that I could attack the connection points with my test light while still leaving everything attached. The rod from the ignition switch moves like I would expect it to but in the acc position, I get no 'fire' to any post except for the ones powered by b+. Switch to run and everything comes to life (I made sure to have the coil on/off toggle switch to 'off' during my testing, hahaha). It appears to me that something is amiss with the spring(s) or something in that acc position. I mean the rod translates past the acc position on its way to run and everything works in the run position and the start position. If it were just out of alignment or something, I would expect that I would get fire to the acc connections at some point in the rod travel, maybe not right at the acc key position but it should become hot somewhere before I hit the run position. Anyway, look out IHPartsAmerica.com, an order is coming your way!

Good on ya! I think overall you got pretty lucky on this deal and you learned in the process without it breaking your piggy bank. Also keep in mind that if your dizz is a Holley curved points as we believe, but have not yet confirmed, you can always revert back to breaker points in a pinch. For that you would need to have an approximate 1.8 ohm ballast resistor in place to interrupt the switched b+ to the coil and a bypass resistor feed wire from the starter solenoid 'r' terminal that would run either to the coil + terminal, or the coil side of the ballast resistor. Six of one, half-dozen of the other for that wire routing. Actually, taking the time to set things up so that you can easily make the switch over to points in the event of a p-tron failure way out in bfe is a wise, boy Scout be prepared fall-back. Points aren't sexy, but if they get the engine fired up and get you home...they're a damn sight sexier than pushing the sumbitch or paying a hook to come tug on it! Know wut I meen, vern? I can baby step ya through the process for a clean setup if you want to do the leg work at some point. Not really much to it though.