What the sock?!

[tunnelrider]

Hi everyone, in my southern mid winter madness of intending to just replace the timing chain I'm getting further and further away from completing the task.. While splashing the more exposed than normal bike frame with some paint, the latest tangent involves a Dyna Coil, a severely corroded HT plug and a cracked-right-through coil bracket.
The coil was still held up by one half of the bracket.  The rear HT lead socket in the coil is shiny and perfect, the front one has the corrosion and is also the side of the bracket that was cracked and not held to ground properly.  Would anyone be able to inform me if the corrosion would be from the cracked bracket or maybe water finding it's way into the front socket? Both HT leads have been well sealed by rubber boots, however, perhaps it is possible the '94 Dynacoil has been letting in rain etc around the centre shaft and making it's way to the front socket?  Looking at the HT plug it's amazing it still was firing OK!

[Barry]

I very much doubt the bracket has anything to do with corrosion in the HT connection.

Other than as a temporary measure don't be temped to mount the coil with tie wraps.  Any coil that that has the laminated core exposed at either end is designed to have both ends connected to a metal mounting bracket in order to complete the magnetic circuit of the core.  It's not that it won't work if you don't, but it will be less efficient because leaving the core ends open circuit changes the inductance value of the coil.

[tunnelrider]

Hi Barry, thanks for your reply.  Unfortunately my first picture has some green masking tape covering the front end of the bracket that was attached to the front end of the laminated core. This would have had no ground with the cracked bracket but the other end of the coil was still grounded ok.  Anyway, unlikely to have caused the corrosion. Yes this will be repaired and coil grounded properly before using the bike again, still got a number of jobs left to do.  Other than looking at the quality of the spark, does anyone know of a test that may indicate the health of a coil?

[Barry]

Testing coils under the voltage stress of operation is not easily done other than as you say by observing the colour and strength of spark.

You can measure the primary resistance which for a green Dyna coil (if that's what it is) should be a nominal 3 ohms. Not sure what the secondary winding resistance should be but it will be in the order of 10k -15k ohm. Maybe the Dyna web site will give a specific figure.

[Bob_Roller]

It appears that the metal that was used to fabricate the adapter plate for the coil, was too thin .

It cracked right at the edge of the plate on the frame that the adapter plate mounts  .

My best guess, is that the rubber boot over the ignition lead at the coil, didn't seal very well and water got trapped in there .

Not a bad idea, to coat the boots and lead with dielectric grease before installing them on the coil .

You also reside in a salt water coastal city, ' salt air ' is not kind to motor vehicles .

[mrclubike]

After 23 years you were due for a new coil and wires
Definitely nothing here prematurely failed 

I have seen this many times

[tunnelrider]

Definitely nothing here prematurely failed 

Thanks for your thoughts all, the bracket was aluminium so it gave a good service 20+ years with the coil you're right, with all the vibration it must've been through.  Think I'll replace it with a stainless steel piece I've got lying around.  Any tips on refreshing a dull corrosion coil socket or is the coil probably past it now?

After 23 years you were due for a new coil and wires

ha ha Mrclub bike you've seen it before thanks for your tips, new coil you reckon.  I've read before you can get cheap coils that will do the job from auto wreckers. Test the spark from this one first, got a few things to put back together.
Cheers Barry for the rough resistance guides and Bob, yeah had decided on adding the silicon grease too. 

[Bob_Roller]

A small round metal brush will work .

A firearm cleaning brush would do the job, but I doubt you have any gunshops available to you in AU .

A small diameter wood dowl split a little bit at one end, then put a small piece of scotch brite type material in the split .

Put the dowl in a drill motor and see how it works .

Found this chart online .

The green coil, is DC3-1 .

http://www.dynatekuk.com/sport_bikes_ignition_coils.html

[Motu]

To clean the coil tower fill it with muriatic acid, leave for 10 minutes and rinse. Jenolite for a kiwi.

[tunnelrider]

Good tips thanks Bob and Motu.  I can get analytical grade HCl acid at work so will use that then try cleaning the result with something like you described Bob.  We do actually have gun shops here in NZ, hunting and duck shooting are popular with outdoor hardy types, plenty of forest and hills to climb here.

[Justin B.]

Very glad to hear that your politicians haven't disarmed you yet!

On Bob's suggestion - you can also use a strip of sandpaper (320 grit maybe) in the slotted dowel.

[tunnelrider]

Very glad to hear that your politicians haven't disarmed you yet!

Ha no not yet Justin but the nanny state is always bubbling under the surface ready to change things for 'the better of the people'.  We do have fairly tight gun laws which means there aren't a huge number of guns floating around to become a toy, which I'm happy about.
Jenolite seems to be phosphoric acid based rather than hydrochloric (muriatic) acid. Most rust stoppers are also phosphoric acid based, while hydrochloric acid is used for pickling steel, which means it is probably stronger. Commercially it's probably cheaper to use phosphoric acid rather than hydrochloric.  Might try phosphoric acid first.

[Bob_Roller]

If you're not pressed for time to get this done, vinegar will work, but takes a few days to a week .

[Motu]

Jenolite seems to be phosphoric acid based rather than hydrochloric (muriatic) acid.

I'm actually using mag wheel cleaner at the moment, I don't know what it is, but it behaves just like Jenolite, so use it as such.  Any sort of light acid will do the trick, if it's stronger then shorter pickle time.  I wouldn't put any twirlly thing in there, you don't want to remove any metal, or worse.  If pickling won't get the gunge out, it's so bad I'd toss it.

[tunnelrider]

I'm actually using mag wheel cleaner at the moment, I don't know what it is, but it behaves just like Jenolite, so use it as such.

Ha ha you're not wrong Motu, +1 for the mag wheel cleaner suggestion, whakawhetai koe.
I had some in the garage from when I tried using it to clean up the cylinder cooling fins (pretty tiresome job and relatively ineffective).  I'd also suspected the coil sockets are aluminium.  I pickled the coil socket in 18% HCl acid overnight first and now, after a number of cotton buds buffing the alum cleaner, the socket seems to have a sheen worthy of a decent spark. Still not in a position yet to try it out with a sparking test though, will be another week perhaps.