Hi, took my car out for a drive today and on return I opened the hood to check things over, I noticed the iginition lead from coil to distributor looked slightly backed off so I removed it to find the HT connection on the coil was full of oil. This was a new coil put on only about 300 miles ago. The previous (original) coil had an oil leak around the top of the body near the top. The coil gets pretty hot, but my engine is stock with stock exhaust manifolds, so I wouldn't expect the coil to have got too hot.

Have I just been unlucky and got a bad coil or is there anything else that could cause coil failure that I have overlooked?

Thanks,

Pauly

 

What does that mean? What does "HT" stand for, and what was full of oil? If your stock coil is getting 12 volts while running that will overheat the coil and cause coil failure. I think you are supposed to have a ballast resistor or a resistor wire going to the coil. I just read a quote supposedly from a GM service manual that said that coil failure in that situation could take 4 to 10 hours. That really bothered me because I was thinking if I had my coil hooked up incorrectly I might be fine on my typical 1/2 hour or even 1 hour drive but then if I went on a longer trip I could end up toasting the coil.


Also, is your ignition stock? Points + stock coil? Anybody mess with it previously? Installed pertronix or some other pointless (no pun intended) ignition?

 

Hi... HT stands for "High Tension" and refers to the high voltage side of the coil connected to the distributor, (LT refers to low tension and is the 12v side of the coil) I guess it might be just a UK thing, sorry, I have a hard enough time remembering to call the bonnet a hood!

The Large connection socket on the coil was filled with oil, on cleaning it out I could see it bubbling up from the bottom.

It isn't a stock coil, its a pertronix flame thrower (1.5 ohm resistance) and I have bypassed the resistance wire as per the instructions supplied with the coil so it receives 12v at full system current.

I have crane XRi points replacement system.

Regards,

Paul

 

High tension is a correct description, and used by many of us here too.

 

Coincidentally, I have just emailed a similar queston to the pertonix people. My question is, can the flamethrower coil be used with a stock points ignition, and if it is, can it operate on 12v, and if it is used with a resistor wire will it still work properly.

Although there are many discussions of pertronix on this forum, i have not seen that question answered. I did find a discussion on another forum which complains about the issue not being discussed properly on the pertronix website.

So, getting to your situation, it is not clear to me that the 1.5 ohm Flamethrower coil can be run on 12 volts. Pertronix tell you to run their module on 12 volts, but do they specifically say the coil can be run without a resistor? They also make a 3 ohm coil. It is possible that the 1.5 ohm coil requires a resistor (wire, or ballast resistor) and you many have just proven this point by destroying your coil by giving it 12 volts continuously.

Except, Pertronix claims a resistor is NOT necessary for any of their coils.... so why did 12 volts ruin yours?

 

Hi again, yeah... don't know why its busted, think I may have just got a bad one, in the instructions for my coil it specifically asks for the ballast resistance to be removed.

P.

 

Ah ok, no worries then, so many automotive terms are different between the UK and US its difficult to keep up sometimes!

Pauly

 

I'm not an electronics expert by any stretch but I think if you are running stock points you need to run the 3 ohm pertronix coil as otherwise the current passed through your points would burn them out excessively quickly.

P.

 

Will it work like a "flame thrower" if you throw a match on it ????

 

The oil functions to cool the windings ... it should not leak out. How is the coil mounted? Stock has the coil at slight angle. If angle more acute than stock ... the windings become uncovered and overheat ... boils the oil ... pushes oil out the top.

*edit* be careful with any coil/transformer oil ... some contain VERY POTENT carcinogenic cpds (i.e. polychlorinated biphenyl aka PCB).

 

I know the oil shouldn't leak out! that's how I know its shot....!

Its mounted in the stock coil bracket

Thanks for the tip on the chemicals, I'll stay well away from them...

Pauly

 

Well, took coil back to vendor who was happy to replace it with a new one.... will see if this one does the same thing!

Pauly

 

Hmm, the thing failed it sounds like because it boiled out. No resistor or current limit with a 1.5 ohm coil and 14v applied with the engine up to speed it will be producing about 130 watts of heat, which is a lot of heat. If their unit is supposed to run with no current limit it would have to be built very tough.

 

It isn't a stock coil, its a pertronix flame thrower (1.5 ohm resistance) and I have bypassed the resistance wire as per the instructions supplied with the coil so it receives 12v at full system current.

I have crane XRi points replacement system.

Regards,

Paul[/QUOTE]

I'm not sure you should be bypassing your resistance wire.
Have a look at what Crane says as far as ballast resistance.
http://cranecams.com/pdf/90001700c.pdf

 

Heya, that link seems to be dead...

What did it say?

I had the crane unit hooked up to the ignition directly even before installing the new coil and bypassing the resistance wire because the instructions for that said it needed to be connected up that way

Paul

EDIT: Ok... link is back, guess the crane site was just down. I see what you mean... but now I'm even more confused! The Crane module instructions ask you to ADD resistance to a 1.5ohm coil.... and wire the module around it (how I had it set up pre coil replacement) but the instructions with the coil asks you to REMOVE the resistance thats already there... hmmm

EDIT 2: Just dug out my original instructions for the Crane Module.... they are different to those in the link.... figure 7 in my instructions has the module +ve wired to the other side of the ballast resistance. Think I'll have to call Crane Tech support to bottom this one out

 

I kind of thought that might be the case, No reason to nee that much current to get saturation on a hot rod coil.

 

Hmmm... well a call to Crane Tech support didn't exactly clarify things, but gives me something else to try.

Basically they said that the Ignition Module needs reduced current as otherwise it'll fry (basically its designed to run as a direct points replacement with the same ballast resistance as points) This means I've been running mine 'wrong' for the last 18 months, though it is actually correct per the instructions that came with the unit (version 90001700b, dated 2004, of the link posted here with a different wiring diagram). Crane tech support helpfully denied any knowledge of this previous version of the instructions... sigh!

However, none of this should have impacted the coil at all as it is meant to run with the resistance removed and shouldn't care what it is triggered by, whether by standard points or by the crane (albeit the crane probably outputs a different trigger 'waveform' and the difference between this and the points dwell waveform *may?* generate more heat? in the coil)

The way I have things wired up currently if I remove the separate feed from the fusebox to the coil positive I will have the "correct" wiring as specified in the linked pdf (I left the original ballast resistor wire in place in parallel with my bypass) the coil will get less than recommended current to the LT side, but provided everything runs that shouldn't matter?

A bit more googling turned up some other examples of people experiencing leaking pertronix coils, so perhaps I just had a bad coil AND an incorrectly wired igniton module? I'll pull the ballast resistance bypass wire tonight and report back on results!

Thanks for all your help guys, I'd never have thought to check the web for instructions for something I already had instructions for!

Pauly

 

I basically went through this same issue with the older Crane XR700 unit. Part of the reason I kept that Crane link in my bookmarks.

The XR700 was installed (not sure why) by the previous owner just before the car came out of mothballs. I drove the car for several months (mainly short trips) and noticed that the coil seemed much hotter than I thought it should be, and the module also seemed hot. The first thing Crane tech asked was whether I was running ballast resistance. I had no idea how this thing was wired up since I didn't install it. After closer inspecion I found that the previous owner had wired 12 volts with no resistance to the coil. Tech told me I was lucky I didn't fry the module, coil, or both. They suggested using the stock wiring on the coil.....meaning the resistance/override combination. It's run cool with no problems for 5 years now.
I would like to upgrade to the XRi someday.