OK, Gearheads!

dolluper

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Jul 19, 2004
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Re: OK, Gearheads!

Yeah I remembered it was a bad coil <br />a MSD BLASTER SS it only crapped out when you hit it hard very strange sent it back and went through 2 more then the next was great still rocking Must of sent us the junk up here. A little birdie twigged my memory the guy who owns the car :D
 

kenimpzoom

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Jul 13, 2002
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4,807
Re: OK, Gearheads!

With all the backfiring through the carb, remember Holleys dont like that, you can blow up the power valve if it doesnt have the new style check valve in place.<br /><br />Ken
 

LubeDude

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Re: OK, Gearheads!

And the winner is?????<br /><br /><br />
Originally posted by dolluper:<br /> Yeah I remembered it was a bad coil <br />
Pdrm0034.jpg
<br /><br />I cant believe I was able to get a picture of this?<br /><br />Ya think just maybe this is the problem? It even does it with the coil wire in place.<br /><br />I never noticed it when I was doing the Compression test as I was turning the key, but when I hooked up the remote starter and turned the engine over while under the hood I could hear the snap, snap. snap.<br /><br />Sometimes its darndest things. :confused: <br /><br />Thanks all for you support on this one. Hey, I aint afraid to ask for help!!
 

dolluper

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Re: OK, Gearheads!

Nice picture, glad she's figgered , watch out those stock ones might do it again with the pertronix .
 

LubeDude

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Re: OK, Gearheads!

I ordered the pertronix coil that goes with the ignition. Ill paint it black so it looks somewhat original. Its all hidden under the shielding anyway.
 

LubeDude

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Re: OK, Gearheads!

Didnt have to paint it black, it came black, just peeled off the flamethrower decal, looks better on the computer monitor.
 

dolluper

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Re: OK, Gearheads!

Don't forget to turn your impact to the lowest setting when you install it :D :D
 

Skinnywater

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Re: OK, Gearheads!

:)LubeDude I'm glad a simple inexpensive coil rectified your problem. <br />Maybe you'll get lucky and after you run it a while the compression will come up on that low cylinder.<br /><br />I love it when gearheads get together and work out a problem. It's usually the most valuable and lasting lessons a gearhead gets are the ones learned among his peers.<br />And it's completely with-in that spirit that I'd like to take this a step further.<br /><br />As in the ASE tests.<br />Technician A says that a coil that is able to produce the kind of KVs shown in the picture is more than ample. With the secondary wire removed the spark is only completeing its circuit to ground. Technician A also says that if that spark is also present when the secondary wire is properly installed then there has to be to much resistance in the secondary wires, distributor cap, rotor, spark plug or a combination of that list.<br /> :confused:
 

magster65

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Re: OK, Gearheads!

Hey<br />Good news... now how about a picture of the car?
 

LubeDude

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Re: OK, Gearheads!

Originally posted by magster65:<br /> Hey<br />Good news... now how about a picture of the car?
Oh, "The Car" :eek: <br /><br />Try to get one up tomorrow. A picture that is. ;)
 

rayjay

Petty Officer 1st Class
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Jan 21, 2005
Messages
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Re: OK, Gearheads!

Once at the shop we had a Kaw 1100 coil arcing over to a rubber covered oil cooler hose. :confused:
 

LubeDude

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Re: OK, Gearheads!

Originally posted by rayjay:<br /> Once at the shop we had a Kaw 1100 coil arcing over to a rubber covered oil cooler hose. :confused:
Actually not unusual, there is a lot of carbon in some rubbers.
 

dogsdad

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Re: OK, Gearheads!

Great pic, Lubedude. Have you considered taking on photography as a profession? ;) <br /><br />As for Technician A...I'll throw a couple of things out there: first, it's one thing for the coil to be able to arc through an inch of air at atmospheric pressure, but to do it at 9, 10, or even 12 times atmospheric pressure is a different situation altogether, even with only a .030-.050" gap. If possible, the arc will take the path of least resistance. As the photo suggests, it may be a carbon track, dirt, or whatever---even cracks as Ken suggested.<br /><br />Second, Technician A is suggesting that if that spark is also present when the secondary wire is properly installed then there has to be to much resistance in the secondary wires. Kinda right, but mostly not because if you see what you see in the photo, there is no way that the coil will actually fire a plug, even if you did go to the trouble (wasting time) of hooking everything up to see what would happen.<br /><br />The point I am trying to make is that there are cases of too little resistance, and there are cases of too much resistance. It depends on the component. The arc on the exterior of the coil is a case of "not enough" resistance. Sometimes, if a plug or its wire has too much resistance, there can be cross-fire to another plug and is most apt to happen when the other plug/wire is not under compression.<br /><br />Good grief...I'm babbling. <br /><br /><br />-dd-
 

LubeDude

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Re: OK, Gearheads!

What about if none of the wires wire connected to anything? Which they were not.
 

dogsdad

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Re: OK, Gearheads!

In that case, there's a low-resistance path, and it's on the exterior of the coil in your photo.<br /><br />Maybe I could have said it better---the insulation on the wires, the ceramic (or whatever it is) material the coil tower is made of, all that stuff, should be high resistance in order to contain the high voltage output of the coil. The lowest resistance present should be path that you want the spark current to take, all the way to the plug gap. When the resistance of the insulation on your spark leads, for instance, is lower than the resistance of the spark gap, you tend to have arcing spark leads. The problem is that the spark gap of the plugs is a very high resistance, and especially when the combustion chamber is under compression because air is an insulator---and moreso under compression.<br /><br />Make sense?<br /><br />(I'm not a pro gearhead, though I know a bit about engines and such, but I am an electronics guy and electricity is my thang!)<br /><br /><br />-dd-
 

dolluper

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Re: OK, Gearheads!

If too much current goes through a wire, it can overheat and melt. The amount of current that a wire can handle depends on its length, composition, size and how it is bundled. Let's take a quick look at how each of these properties affects the wire's current-carrying capacity: <br /><br />Length - Each type of wire has a certain amount of resistance per foot -- the longer the wire, the larger the resistance. If the resistance is too high, a lot of the power that flows down the wire will be wasted; the energy lost as heat builds up in the wire. Ultimately, heat build-up limits the current-carrying capacity of the wire, as the temperature must not get hot enough to melt the insulation. <br /><br />Composition - Automotive wire is usually composed of fine copper strands. Generally, the finer the strands, the lower the resistance and the more current the wire can carry. The type of copper used has an effect on the resistance of the wire, too. <br /><br />Wire gauge - The wire gauge, or size of the wire, also determines how much resistance the wire has. The larger the wire, the less resistance. The smaller the gauge, the larger the wire -- so a 16-gauge wire is bigger than a 24-gauge wire. Wire gauges go all the way down to zero, which is also called 1/0 (one aught). Even bigger than 1/0 is 00 (2/0, or two aught), and so on. The diameter of a 4/0 (four aught) wire is almost half an inch (1.27 cm). <br /><br />Bundling - The way a wire is bundled affects how well it can dissipate heat. If the wire is in a bundle with 50 other wires, it can carry a lot less current than if it were the only wire in the bundle. <br /><br />When a high tension electricity passes through a cable it builds up a surrounding electril field that frees oxygen into the surrounding ai r and it forms OZONE this OZONE attaches to rubber and will make rubber detearoriate
 

kenimpzoom

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Jul 13, 2002
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Re: OK, Gearheads!

I am a bit confused.<br /><br />So lube, did the new coil actually fix the problem?<br /><br />Are you saying that with the coil wire on the coil and grounded, the blue spark was still there?<br /><br />Ken
 

Skinnywater

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Re: OK, Gearheads!

Kinda right, but mostly not because if you see what you see in the photo, there is no way that the coil will actually fire a plug, even if you did go to the trouble (wasting time) of hooking everything up to see what would happen.<br />
DD, I was with you until here. Keep in mind that coil was capable of producing great performance.<br /><br />Remember LubeDude said;
I dont think its a weak valve spring, it runs strong all the way to 6,000. Only pops at initial acceleration.
That OEM coil has approximately 150:1 ratio of primary to secondary voltage. The application of 12 volts on the primary will produce a maximum of 18,000 volts on the secondary. I say maximum because there is a cycle time or rise time of the coil. If the coil is asked to fire before fully charged then something less than the maximum voltage will be delivered.<br />That rise time or saturation will be severely less at 6,000RPM and mixture density would burden a weak coil far greater than at crank speed or initial rich mixture acceleration.<br />And the Pertronix switching actually allows the OEM coil to charge more efficiently.<br /><br />That is an excellent picture LubeDude captured. That’s why it says so much. It shows a dual current path that is not indicative of a carbon track. The ionization gap as shown is closer to 3 inches than 1 inch.<br />Even at atmospheric pressure more than sufficient voltage was available to ionize the gap and the amperage flowed across the gap creating a fine, thin blue arc that typifies a strong spark.<br /><br />Keep in mind also;<br />
....It even does it with the coil wire in place......
For sure, every leak as shown from the coil secondary is a misfire. Not a "pop on initial acceleration" but a substantial misfire.<br /><br />As in? dit,dit,dang,dang,...dit,...dang,dang..,dit,dit....,dit at 4,000RPM and flat fall on it's face at 6. <br /><br />LubeDude is it still fixed? Did you inadvertantly change something when you replaced the coil?<br />I know coils are cheap but you might want to hold on to that one for a spare though. ;)
 
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