So I bought an old P71 a week ago. 2010 with 99k with a misfire, plug blew out of the hole on cylinder 3. Took it to my mechanic buddy, he attempted a fix but it just blew out again.
I fixed it HOPEFULLY permanently yesterday and today. I drilled the hole out for the 18mm spark plug. Put in an insert covered in a liberal application of red loctite, use a “spage” tool to mushroom the top of it into the walls of the spark plug hole. Waited 24 hours to let the loctite cure on that insert. Stuck another insert in that fits inside the original insert that fits the OEM sized plugs that the Vic uses. It’s currently curing right now, and it’s top is mushroomed into the the inside the the bigger insert. Tomorrow I’ll stick a plug down into it, install the new set of ignition coils I bought for it, and fire it up and see.
The bigger insert had an edge that stuck out from the threads. My guess is to help hold it, now its driven into the aluminum head and shouldn’t ever come out. Same with the insert that is inside the previously mentioned insert.
Theres a fresh set of 7 plugs and ignition coils in the rest of the cylinders. Just wanted to wait to stick the plug in so I didn’t screw with the 2nd insert.
I’ll find out tomorrow what’s going on with it. If it all works, like I’ve prayed to the automotive gods for, I’ll be doing victory donuts in the gravel lot where it’s parked.
I’ve put the title in my name but nothing else, no plates or insurance. Wanted to fix it before I spent any money I didn’t need to spend on it.
Pics of when I first brought it home(well my business’s yard) for your time. Drug it home on my work trailer. It’s still chained down in these pics, also got some pics of its underside while I could still walk under it.