Update(9-16-2017)
Ford dealer told me $4,200 for a head swap all said an done. He had just quoted someone else about a single head swap. (Mine is passenger side head)
Mom an pop garage (James garage of Albany Oregon) told me he doesn't feel comfertable doing the head swap, and suggests swapping the whole engine because he's seen too many problems with people having head swaps (and or head gaskets) done. He quoted $5,200 for the engine swap all said an done. Not bad for a 0 mile engine, he said it comes with 3yr 30,000 mile warranty.
Now I'm trying to decide what's the next move.
Has anyone had an insert custom made bigger than 3/4"? I have a buddy whose a middle school shop teacher and has access to a lathe, I'm thinking about doing a 13/16 or 7/8 in threaded insert, and make my own tap that has a ledge to make a ledge for the insert to stop on.
I'm wondering what's the max size I can tap into the sparkplug whole without getting into the water jacket?
I also am wondering if I should done a hard aluminum billet insert vs steel insert?
Any help from machinist, mechanic, metlergist types would be much appreciated.
Agentt3
This ****** me off! Is this just because it had been inserted before or do they ALWAYS recommend to most extensive expensive repair in every situation?? Probably!! Why I hate garages!!
The way you did it is THE ONLY way to do it!!
Sorry I'm late to the party on this thread.
Any way to do it is fine.
You could even do the worst and get a larger thread spark plug no fouler and cut a notch in it to make it self tapping and/ thread hole with tap and loctite that in OR a completely different plug with larger threads and same idea. Not ideal but I would work and be better than the ridiculous amount of money they want you to waste. GOD I hate people!!!
The worst case scenario is you pull the head and take to a machine shop. They can weld the whole damn hole shut and start over. They can put an insert with tons of threads 20X better than factory but removing head is what we want to avoid but these buttwipes would pull it off and put the same crap design on again!! Did I mention I hate people???
To answer one question about how big you could go...as big as you can adapt it down to fit a plug. No water to hit around there.
The only thing that even concerns me is the different ways different inserts use to keep it in place.
All kinds of swedgers or rods or center threaded "lockers" etc that are used to seat it or lock it into place.
I would think the best would be it you could have a slight countersink or bevel on the hole in head and had an insert that cork style seated into the bevel and then staked it into place. Or maybe just as good to have no bevel and simply stake around insert.
I think that ANY insert gives you better stronger threads to the spark plug but not necessarily attachment TO the head.
I think you will be fine though.
Great work!!! I would use antiseize on this plug threads only and don't overtorque it.
24ft lbs max....maybe even 18 if it feels tight enough.