Right, I spent some time cleaning the corrosion off the cap terminals. Was pretty proud of myself! I even sandied up the br*** terminals on every plug wires making sure they are tight in the socket after cleaning the distributor sockets up, etc. I'm pretty particular about grounding, have 2/0 battery cables, I even bonded the cylinder heads together, and direct to battery ground etc. Distributor has a good solid bond with the block. After all this I figured there would never be any problems. The humidity has exposed the weakness somewhere though. Has to be the insulation. More dielectric in the boots will help, but hopefully OEM type plug and coil wires will tell the tale.
Yes, I would say so. 2/0 cable direct to block, starter, solenoid, + battery terminal. Another heavy cable from block to frame, and another from firewall to block. Both cylinder heads bonded together, and on to battery. I'm real particular about clean tight electrical connections = Happy Electrons. It pays to do this, and doesn't cost anything really other than time. That's why I'm bummed lol
Did you try a different coil? Be sure correct one, I ***ume external ballast resistor? If so when it's running be sure the power is going through it. That Pertronix Ignitor and Flamethrower coil puts out 40kV. Has it been running o.k. or is this new? That may be too much combined with the high humidity. Sent from my SM-S320VL using Tapatalk
Well I thought about that. Running with no ballast. It's a fairly new coil, less than a year. Epoxy potted Flamethrower, 1.5 ohms. The Flamethrower coil is capable of 40K volts, but it shouldn't ever get even close to that, especially at idle. It will definitely run a little hotter with full time battery voltage than a stock coil & ballast, for sure. That was one reason I backed off on the plug gap. It should keep the coil temperature down. You're right, it may be the older style materials, the closer spaced cap terminals of a point style distributor is more prone to this. But how to explain then, the coil itself - their coil - with extended tower, is alternately arcing from the coil wire boot to both pos + and - neg terminals. Gotta be the insulation materials of the coil wire there.
But how to explain then, the coil itself - their coil - with extended tower, is alternately arcing from the coil wire boot to both pos + and - neg terminals. Gotta be the insulation materials of the coil wire there. I agree about insulation. The problem is if something ever arcs it usually leaves a carbon track and then it's more likely to arc from then on. Pertronix has a great website with support answers. You may find it there otherwise I would call them tomorrow. Pertronix Performance Products Pertronix IGNITION PRODUCTS. Ignitor Electronic Ignition and Flame Thrower and Second Strike and DigitalRevLimiter Sent from my SM-S320VL using Tapatalk
Sure do, I should check a couple just for grins. I'm sure they are fine though, they are only a year or so in age and not too many miles. I think they were 7mm generic from Speedway. Install your own end, socket or male type depending.
Don't believe so, not at idle anyway. Checked the coil wire and the #5 wire (longest) they come in at 500 and 2000 ohms.
hmmmm, if you had a failed rotor, or a burned out or missing carbon ****on in the middle of the cap, wouldn't the spark try to travel from the center coil terminal or coil wire to whatever is handy nearby? Arcing across the top of the coil or cap seems to suggest the high tension current can find no easy path. unless it has a conductive film deposit or something dirty on it. also, is your rotor phasing pointing at a cap terminal when it fires, and is not aimed at the dead air space between terminals when it fires? WHY BE ORDINARY ?
Both are new, or near enough, and good quality parts. The rotor will sometimes burn through to the distributor shaft with cheap parts. That's something I need to check, I guess. Am running pretty high initial timing. This isn't a new thing though, what is new is the garage has been like a sauna for weeks, the humidity is off the charts in there. So it's definitely an "ignition tester" situation. Dielectric grease in the boots should help, but I kind of want to see how heavier insulation on new plug wires works out all by themselves.
I think you answered you own question. You have a souped up coil hooked your to full 12 volts. The engine you have was designed to with a weaker coil that runs on 6 volts and only 12 volts for starting. That’s causing your problem, with all that voltage ,it’s finding an easier path to ground than going to the spark plug. Either lower your spark out put or make the path to the plug more desirable . Bones
Have to agree with that of course, but are there really that many differences between plug wire insulation? The coil itself too is designed for full time battery voltage and therefore should not be arcing to the terminals tegardless of the system it is installed, unless it's "seeing" an easier path than moving on to the distributor. The plug wires are fairly low resistance and the plugs are non-resistor type. They were NOS and have some kind of crust between the shell body that might be presenting a leakage path to ground. They burn very clean though. They are supposed to be a cooler plug, and have a much shorter nose than what I was running but they don't act like it from the way they look.
Electricity will take the path of least resistance. Possibly the wires have deteriorated to the point where they have increased resistance?
Electricity will take the path of least resistance. It travels through the wire and jumps the spark plug gap. An oscilloscope can be used to determine spark plug gap by the height of the spike when each cylinder fires. In your case, the electricity can't get to ground through the spark plug so it builds up to a higher voltage until it has enough voltage to go past or through the wire boot or dielectric grease and to ground via the clip on the cap. It could be a resistor spark plug that the resistor has failed. It should cause a miss on that cylinder.
New plug wires should be here today. Looks to me as if voltage was blasting through the rotor to the distributor shaft. I have one of the later blue rotors I can try.
looks like the rotor may not match the cap in height. should be a shiny spot where the carbon ****on rides.
Yeah there is one, it just doesn't show up very well in the picture because I tried to make the carbon track the focus. We'll see if a blue Motorcraft rotor makes any difference? It's made of a different type of material with a hollow scoop below ****on area.
If the rotor is burnt through, you wouldn't have spark jumping from a plug wire tower to the cap screw.
It's not burnt through. But, you should be able see the carbon track or etched appearance in the pic pretty clearly, kind of a half circle.
Fresh wires, cap and rotor seemed to have solved the issue, no arcing that I can find. The insulation on the "old" wires was only a year or so, though deteriorated in some spots due to heat. Everytime I try to cheap out on anything it always comes back to bite me. We'll put everything on the scope soon and see if things look better on the patterns. Edit: The scope traces at least display properly now in parade and superimposed and generally behave like they should near as I can tell, all that previous shorting/arcing to ground and general wire ****ery must have really confused the machine. Can't interpret scope patterns too well but every cylinder secondary trace looks the same, and the primary waveform displays properly now. REALLY great tool to have, and they are dirt cheap these days.
The scopes are really cheap now a days Picked up a snap on vantage 2 a few years ago with a ton of accessories, books etc for a bottle of rye !! I don’t use it a lot but it does come in handy at times.
That auction site. They can usually be found cheap at yard sales but I was lazy and just waited till one went up BIN that included the manuals and the cord connections and inductive pickup. These are usually missing. The Heathkit that I bought was sold either as a kit or factory wired so it can be a roll of the dice on the kit versions. They will need some work on the power supply typically. Cool thing was it took about 2 minutes after hooking it up to figure out the ignition had some real problems. I was first going to take it into a shop that has a scope that was recommended to me. Seemed to me though, for about the same price as a diagnostic session I could get my own scope. Now that things are squared away, I still might take it in and have someone who really knows what they are looking at put it through the paces and see what's what, and maybe get a little instructions what to look for with the waveforms. IO-20
Ok, took it for a spin and it runs pretty smooth out on the highway, but it backfires fairly regular at idle. Never did that before. Guess it's gotta be crossfire somewhere, but I can't see anything in the dark. Maybe try moving the wires around?
The thing about scopes was keeping them working. Whether by poor design or intended design, they seemed to need leads quite often.
What specifically was the problem? The pickup? I can see maybe in a shop environment, where they saw heavy use, getting dropped or banged around. Most of us weekenders types , they didn't see too much use. This worked in my favor at one angle. Was worried the unit I bought might have been rat-fvbked of the tubes, I looked over a schematic before it shipped and saw some of the vacuum tubes it used are also very popular guitar and hi-fi types. Uh-oh. Was glad to see it had its full complement of tubes, including, two Mullard 12AX7s, I swapped those out with some good but very tired Telefunken to my Dynaco stereo tuner - and these are fresh as a daisy and sound great. The "civilian" scopes just didn't rack up a lot of hours. A series of highly unlikely events (ha ha) led me to make a mistake. Backfiring - had two of the new plug wires swapped!! Duh. I knew it ran ****ty but I couldn't believe I made such a rookie move. Sure runs better running on all 8. Jeeze.
The Jalopy Journal
