[Boxstard]

Originally Posted by DrRobin

When you measure the resistance to be less than 0.7 ohms, that is just the primary coil and my guess would be that it is the secondary which is more important. You can measure the secondary resistance, but a better measurement would be the insultation resistance, for which I haven't seen any figures.

If the insulation has cracked, unless you get all of the moisture out before it is sealed with epoxy you will still compromise the insulation resistance and therefore might end up with a weak spark. I would only do this as a short term fix until new coils can be obtained.

It took me 3 hours to change all six coils/plugs and coils were £31 each in the UK, I doubt it is really worth the effort of removing a coil, drying it out, filling with epoxy and re-fitting, well not in our current autumn climate of cold temperatures and rain.

If you were a little closer, you could have 6 Beru coils, all with at least one crack, but the postage would be more than they are worth.

PS anyone in the UK is welcome to them if they pay the cost of posting from Northumberland.

I’d agree that insulation resistance is a key characteristic that correlates more on strong (or weak) spark.

I’m routinely checking or actually replace spark plugs, like every 10K miles or so, when I also inspect coils. It takes me less than 2 hours and never bother me doing it. Never had body cracks but repaired one tube with electric tapes and it has been working fine for 2 years.

Thanks for your offer, I can afford new ones, the question is really if mine is bad or not performing as it should and what is effective evaluation method, as it seems clear that the service life is all over the map based on responses here.