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MG Midget and Sprite Technical - Leaking coil

I noticed the HT lead from my coil was wet so pulled off the waterproof boot and it was full of liquid. Investigating further I noticed a screw in the hole where the HT lead sits that is supposed to seal in the liquid, but it was clearly not very effective.

As the coil is not a year old yet anyone know what the liquid is?

Also, who in there right mind would mount a coil so it can only go in the HT lead down position? (It's an M reg RWA).

Rob
Rob aka MG Moneypit

The liquid is probably an insulating oily substance

Mounting the coil neck down should guarantee that the contact joints on the windings are always under the surface and less likely to get sparking from any potential bad joints

So they tell me



OK already, so they TOLD me when they had to keep me eddicated/advised professionally


Believing what THEY told me is optional ;-)
Bill sdgpM

I put my coil down by the tirangle cut out close to the front suspension.... top facing top

My thought it will get better ventilation and more room for something else in its orginal location

Prop
Prop and the Blackhole Midget

Rob,

Its oil to keep them cool
Flip
Flip Brühl

If most of it has leaked out is the coil U/S or if someone knew what the oil was could I refill it?

Rob
Rob aka MG Moneypit

It will be transformer oil I reckon

But how much you would have to pay to get enough to refill a coil I'm not sure

Nor am I sure it would stay in if you did refill it

Remember it IS supposed to be in there for the reason I mentioned

Prevent arcing in oil rich atmosphere, followed by a bang


P O S S I B L Y any suitably thin oil might do the trick

who knows?

Do you know how it has sprung the leak, is the cap screw loosened?
Bill sdgpM

The seal is very crude. A self tapping screw, flat washer and rubber O ring. The screw hasn't centred while screwing into whatever it screws into. Guess who supplied it? Begins with M ends with S.

Rob
Rob aka MG Moneypit

Guess who supplied it? Begins with M ends with S.

M-other ... S-uckers Moss ?

I bought my reacment coil from the local auto parts store (auto zone)... they even had it in stock, and at a fraction the price of the "green algae store" ... I just took the coil into the store and they looked it up ...easy peassy

I dont know that id risk repairing something like that, that much current and hooked up to the electrical system could become a catastrophic adventure worth writing about in road and track mag.

Prop
Prop and the Blackhole Midget

If it is ordinary transformer oil you should be able to get a pop bottle full from any any firm that does transformer servicing.

The most common type of transformer oil I have had anything to do with is called Diala B. I think it's a Shell product, but I'm not sure. It is commonly used offshore to isolate high voltage terminations in subsea umbilical termination boxes where no lubrication is required as it is (apparently) not an effective lubricant. Which is why we didn't use it in the 3 phase motors driving subsea hydraulics even though the voltages present were the same as in the termination boxes - anything up to 10kVAC. The motor bearings need a good lubricant of course.

Diala B is also the recommended oil for Oxford oil-cooled welding plant, which are brilliant machines. Mine was stolen about 15 years ago :-(

My understanding is that transformer oil is basically coconut oil FWIW, which you can buy in the supermarket, so that might be worth a try. On the other hand it might be less hassle to buy a new coil.

As an aside all the '70's Fords I had (I'm talking Cortina/Capri/Granada/Escort) for some reason had the coils mounted just inside the front grille where they were assaulted by all the crud the weather could throw at them and they failed regularly, so I always relocated them backwards to the inner wing and mounted them terminals downwards, following my Dad's advice. It seemed to work well as I recall.
Greybeard

The coil on my Sprite exploded once. Maybe exploded is overstating the loud "pop" noise that sounded under the bonnet. I had left the ignition on with the engine not running. When I opened the bonnet the plastic end cap had blown off the coil, the oil was spattered all over the engine and the entrails of the coil were hanging out.

I pushed the wires back inside the tin can and refitted the plastic cap, but the oil was long gone. Surprisingly the coil still worked. I did buy another but it was some weeks of virtually daily use before I got round to swapping in the new coil. The "dry" one seemed to perform just as it always had done.
Guy W

Greybeard,

I'm was thinking a local welding supplier might have suitable transformer oil as it might need changing occasionally but not sure, my 180A Pickhill is still going strong after 25 years of 2nd hand use. Maybe a cheaper option is to drain a failed coil but if the original one leaked it may well be scrap due to poor original assembly so not worth repairing.

Interestingly I enquired about oiled filled welders in the US and they apparently don't do them, just air cooled.
David Billington

As it is not a year old, I would be talking to the supplier and quoting the sale of goods act, or the supply of goods and services act, or maybe a combination of the two!
Dave O'Neill 2

Lets pretend that space aliens have beemed me up scotty and gave me a thorough group anal probing and now im the man of reason

You guys do know that these coils only cost between $20 and $35 usa, even a fancy sports coil will set you back $40 usa

By the time you drive all over gods creation and purchase the oil, have it delivered then the suppiles to actually seal it, then the risk that its actually rebuilt corrctly and wont burn out your $100 rpm tach

Is the cost really going to be less expensive then the price of a new one avg $35

Im sure there are several good used ones on ebay for $10 to $15

I think steven may have one ... he busted a midget last weekend to sell for parts

Prop
Prop and the Blackhole Midget

I just replaced my 1500 coil with one from rockauto.com.
Set me back 7 dollars something plus 4 or 5 bucks shipping. Just slightly larger in diameter than original, so it just needed a bit of bracket modification. But a good deal.....
Paul
Paul W 1976 1500

This thread was discussed between 15/08/2015 and 23/08/2015

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