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The mkiv Supra Owners Club

Coil pack repair....


andrew7

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Hi guys,

 

On changing my plugs recently I found I had 4 of the six coil pack stems with cracks in them.

As I have no noticeable misfire I was reluctant to throw them away and fork out £90 each for replacement packs when in all probability the only thing wrong with them is cracked plastic….

 

So I deciced to attempt a “repair”.

 

I obtained some high temperature, high electrical resistivity epoxy from IS Rayfast in Swindon. This is the “BOND-IT 7050 Super Bonder” epoxy and cost £49 delivered.

 

Finally got around to doing the “repair” today.

 

After removing the packs I cleaned them using acetone (brush it on and wipe off). Acetone evaporates very quickly so there is no residue.

 

Then I mixed up the epoxy and applied it with a small paintbrush to each plug cap stem on the coil packs.. The epoxy starts to cure pretty quickly so it is better to do a couple of separate mixes to get all six coil packs done.

 

All the offending cracks were well filled and I extended the covering to go right around the stems. I also covered the coil pack stems that weren’t cracked as a preventative measure.

 

The epoxy takes 17 hours to fully cure so I hung them up indoors overnight.

 

Re-fitted the packs today and so far all is well, so I could have saved myself a few hundred quid.

I will be taking them out to check them in a couple of weeks to see if the epoxy is maintaining its integrity….

Apparently this epoxy is stronger than the plastic I have put it onto so fingers-crossed………

PS. Anyone want to try an experiment. I've got enough epoxy left to do two more stems. Anyone got a coil pack that is misfiring due to large cracks in the stems?....

IMAG0076a.JPG

IMAG0077a.JPG

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Andrew, did you grind out the cracks to form a V groove & then fill this??? Or were the cracks wide enough to fill entirely?

 

Just thinking that if not then the spark can still track across the crack to your epoxy, and depending on the thickness of this it may or may not withstand it.

 

Sounds like a large amount of cash saved though.... I'm always up for that! ;)

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As I have no noticeable misfire I was reluctant to throw them away and fork out £90 each for replacement packs when in all probability the only thing wrong with them is cracked plastic….

 

£90 each!!! :eek:

 

£45 each + postage here :)

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Andrew, did you grind out the cracks to form a V groove & then fill this??? Or were the cracks wide enough to fill entirely?

 

Just thinking that if not then the spark can still track across the crack to your epoxy, and depending on the thickness of this it may or may not withstand it.

 

Sounds like a large amount of cash saved though.... I'm always up for that! ;)

 

No didn't grind anything. Wasn't going to mess with them too much as I have no spares.

However I did brush the acetone well into the cracks, and that stuff kills anything!...

The apoxy is like water when you first mix it so it flowed right into the cracks.

As it starts to cure you can then add some body to it..

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Does the epoxy used dry hard or does it still retain some flexibilty?

 

I don't know yet Mig...

The guy at Rayfast says the end result will be stronger than the plastic it is attached to and as you know epoxys shrink a little when they cure so it should be a nice strong fit around the stem...:)

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