Don't be concerned. Chances are that any Al particles were blown out as soon as the engine was cranked over. If the plug got cross threaded, use a chase first. It's like a tap, made just for spark plug threads. Make sure that it goes in straight. If the plug goes in and seats well, is tight, and there are no leaks, call it good. If not, you can install an insert. There are special kits made just for spark plugs. I know that NAPA carries them. You basically drill out the hole, tap it, and install a "shell" that screws into the newly tapped hole and lock it in w/ thread sealer.

Sounds okay to me also, but if you're nervous just pull the head and send it out to a machine shop for refurbishment. I've seen quotes of $50 to $100 for revising a head - and about $25 to install a helicoil for the sparkplug. It would also be wise to change the timing belt if you do pull it out. You also might want to look at a realitively new thread restorer call ez-lok (see www.ezlok.com) I guess its thread stripping seaseon?

I agree that you don't have much to worry about, any mechanic worth his salt would grease up the thread chaser real good. As far a heli-coil, that's kind of a de-facto generic term appliet to thread repair hardware. Heli-Coil is actually a brand name that has been hijacked to mean a "thread repair gizmo" about the same way as Channel Lock has had their name snagged to represent all large slipjoint pliers.

The actual insert that people refer to as a "heli-coil" is actually unsatisfactory for spark plug repair. It actually resembles a spring wound from a semi-square cross-section stainless steel wire. I just had to re-repair a Mercedes head because somebody used one of these and the "coil" unwound upon spark plug removal. Imagine my depression when I pulled out the plug and it had a "spring" hanging off it!! Proper sparkplug hole repair requires a solid threaded insert. Guess what, Heli-Coil makes them as well so this is probably the source of confusion...

Not trying to be a picky butt-head but these two things are very different and have specific uses. And the more I think about it, I'm not even sure why I'm harping about it!! Just ignore everything I just said... :-p

Justin B.
83 Turbo

If there were chips there is no way they could get in the oil...

Probably any chips would blow into the exhaust and melt in the cat.. that is about the worst thing... You would never know that happened, and then in a short time the cat would turn the aluminum to dust and it would be on the street as ash....

What the tech did was "Chase" the threads, and it is likely he greased the tap.

Evidently you therefore do not have a heli-coil, and are now forced to find something else to worry about ;-) Mac

If your mechanic knows the tricks, there's a good technique to prevent chips from getting into the engine- he used a tap on the hole, I assume which looks like a bolt, except it's got cutaway areas on it- it makes new threads or restores old ones. If he applied a little grease to the tap, it would catch the chips and not let them fall into the engine.
If the damage was so minor that he was able to rethread it, then it probably only affected 2 or 3 threads at the most. There should not be a lot of chips. Therefore the likelihood of engine damage is fairly small. Not to say something bad might not happen, but it's less than if you were installing a Helicoil. And what is that? Glad you asked. It's an insert, like a thin cylinder of metal, with threads both on the inside and outside. A new thread pattern is cut, larger than before- the insert is threaded in and locked in place (different techniques for different brands- Helicoil is just one company that maeks them) then the inside of it is the size of the original spark plug thread.
As for the chips, basically it's a little late to worry about them, but they probably hurt nothing- the aluminum of the head is soft, and almost certainly blew out through the exhaust with no damage.
Good luck!
--
Rob Bareiss, New London CT ::: '87 244DL/M47- 221K, 88 744GLE- 202K, 91 244 181K, 88 244GL 145K