Helicoil Question

[PatS]

I was checking my spark plugs today and noticed that plug #4 was probably stripped. The spark plug will thread in but not tighten which tells me I will probably need to install a Helicoil. Does anyone have any experience doing this? Can it be done on the car or will I need to pull the head and send off to a machine shop?

Thanks for the help.

Pat

'70 SRL

[Nissanman]

A competent operator can drill, tap and helicoil the head insitu.

[TriniGriffin]

FWIW: repaired #2 spark plug with helicoil, without head removal in 2009 timeframe. Using hand tool (not electric) drilling. Still in the car, no leaks, good compression, makes power.

[notoptoy]

I (With my father) did a Heli coil in a 70's aluminum head Fiat in the car. I learned a lot - first and foremost - be careful torqueing spark plugs in aluminum heads!!
Our process involved the following
1) Piston at TDC
2) We stuffed fairly heavily oiled foam (Like what surrounds an air filter on a lawn mower) into the cylinder
3) reamed the threads with a strong shop vac behind the tool the whole time
4) Thoroughly vacuumed the threads
5) Installed heli coil
6) Vacuumed the new threads again and as much of the foam as would come out, then picked out the remaining foam with hemostats and dental picks. The foam seemed to catch all the metal particles nicely.

It worked fine, and I never had any problems. That little DOHC head was a thing of beauty, what great engineering!

[Nissanman]

One of the first DOHC engines to use a rubber band to drive the cams instead of a chain

[bobd]

Put grease on the tap to help hold the metal chips.