Howdy all!

I searched the archives, but didn't quite find the answer I was looking for.

I have a '94 Impreza with the 1.8 and 220k miles. I picked the car up a year ago with about 180k on it for $350, with a minimum amount of work needed to get it going well.

In doing this work, I replaced the spark plugs. I'm always really careful to thread in by hand first and then tighten, but somehow I got a plug cross threaded. Seeing as it was wedged in there pretty good regardless, and the car seemed to be running fine, I left it as is, knowing I would have to deal with it eventually.

That time has come. The car now is having a hard time starting, at least until it warms up, and feels very much like one of the cylinders is not firing. Fuel mileage is down, check engine light is on, power is way down. I figure I'm due up to have to deal with this dumb spark plug.

So, here's the options as I see them, I'm looking for advice on what might be the best course of action:

1) Remove the plug, put a new one in, hope for the best

2) Attempt to helicoil the thread in-vehicle

3) Remove the head, have a machine shop take care of it

4) Goto junkyard, get a used head. Replace for my stripped head

5) Find another engine

I'm leaning towards number 4 there. Removing the engine and replacing the head is not outside of something I can handle, so I'm not really worried about it, but if anyone has experience with the other options, I'd love to hear from you. I understand I can yank the head in-vehicle, but that sounds like a pain vs just pulling the engine and working on it out of the vehicle. Thoughts?

Thanks all.

 

Considering your mileage, I would just drop another lump in.
You will have to take it out anyway (realistically), so by the time you pay for it to be helicoiled or put a new (secondhand) head on it + gaskets, you would be better off with another engine altogether.

 

Remove plugs and replace. If it doesnt work, so be it. At least youll know where you stand. Always go with the cheapest option first

 

As above, try the cheap option (lets face it you will probably use new plugs anyway on any of the other options so you arent losing anything)

helicoil can be done in situ on a normal flat 4 engine but not sure about a boxer engine (access and chance of swarf in the engine) so I would rule that out in situ as it will probably cause more problems long term.

A replacement engine can cause problems with you not knowing the history etc so my advice would be either a replacement head, or remove yours and helicoil it

 

Throw a new head on it.

 

Well, as it turned out, I had some loose plug wires going into the coil that was causing me grief.

Of course, I still have to contend with this plug eventually, but thankfully not right now.

I might have a handle on a 2.5 that I can rebuild, am I correct in my assumption that pretty much any Subie engine will bolt in? Obviously I'll be having some manner of fun with engine controls, but I'm tempted to MegaSquirt it anyway

Thanks for your input!