[jme]

At first I thought the J20a engine in my SV420 was missing a cover over the coils but I have now figured out it left the factory like that. As a consequence, it starts running on 3 or even 2 spark plugs whenever it gets remotely damp under the bonnet. Is there an aftermarket cover available? Is there any way to prevent water getting into the spark plug holes?

[weelz]

Hi, JME.
You need to replace the boots under the coils. They break down with age, but oddly, they're hard to find here in Australia. Everyone wants to sell you complete coils. Do an eBay search for DENSO 671-4295 Coil On Plug Boot-COP Boots. I paid $56.00 for a set of 4 delivered to my door. Solved all my damp weather and under bonnet wash problems in one stroke. Easy to fit too.
Regards,
Weelz.

[fordem]

NGK 58952 - and when fitting them look for the vent hole at the top and rotate the boot so the vent is shielded by the coil - I also use a light smear of dielectric grease around the top edge of the boot where it seals to the plug tubes.

[weelz]

Interesting comment about the vent holes, I'll have to check that on mine. Agree about the dielectric grease, my kit also said to coat the spring on the boot too. Came with small sachets of grease too. Just had a quick eBay wander, the prices have increased quite a bit in the last 8 months, postage too!