2003 1.8 blew its 3rd cyl plug.
 

My gf's coworker happens to be our neighbor. Today we picked him up to go to work (we carpool and work close to one another).

Robin is a clueless tool less guy, very nice, a real honest dude. So I look at his car and discover the 3rd cyl plug blew out. Used a small pen light and can see the threads are just all F'd up. The plugs look original. The part that bugs me the most is that the electrode is gone. I can see a few small marks on the top of the piston.

Robin and his neighbor "hand tightened" the plug/boot wire and he was able to drive it for about 20 minutes before it inevitably blew the plug out again.

So I'm torn. I'm going to help this guy. I see how deep the plug is in the head and that is a problem if I were to attempt to repair it with the head on. The next thing is, I'm thinking I prefer to pull the head, change his water pump, timing belt and vc gasket. What would be best? Take the head to my machinist and let him fix it? Timeset? Helicoil?

Next is pulling the head off a 1.8. Do I have to pull the intake and exhaust or can I disconnect what is necessary and get the head off?

I'm very proficient with tools, plenty of experience to get it done. I have spent about 20 mins total looking at the top of the motor, mostly letting Robin repeat how he does not get how "it worked" when it was "hand tight".

I'd love any tips you Miata guys have to throw at me. Plus I'll make a pretty penny doing the job. Mainly its a favor, he insisted he'd pay me, as he prefers I am paid rather then a shop.

Appreciate any help or advice guys. I've yet to confirm I'm doing the work. I'm still looking stuff up and figured I'd join and make this thread as I learn a bit of what I'm up against.

You can remove the head from any Miata engine with the intake and exhaust manifolds still attached (assuming it doesn't have some wanky aftermarket header.) On the intake side, you will need to unbolt the diagonal brace which is on the underside of the manifold. It has, I believe, 3 bolts in total, and is not hard to get to. (This assumes that someone hasn't already removed it and thrown in away, which is common.)

That said, doing major surgery on your neighbor's car is always a sticky venture. You will be at fault for every bad thing that ever happens to it subsequently.

There are kits out there to helicoil heads while on the car -- lots of the Ford 5.4L V8s needed them. I don't know how well it works, or how you keep the shavings out of the cylinder.

(or is there a concern that there are bits of the plug still in the cylinder? I can't tell from the original description.)

--Ian

something tells me this engine is done-zo

i was justa bout to go like WHY THE FFF WOULD YOU REMOVE THE HEAD FOR THIS!
there is absolutely no need for that.

if you fix the thread, just make sure you clean the cylinders from any metal shavings..to do so, use a vacuum cleaner and attach a small hose to it (figure that one out) then insert this little hose down the tube and vacuum the crap out of it...

some metal shavings will be left back...insert some motor oil into the silinder and install the spark plug...the shavings will eventually flow out the exhaust...unless they are user bits i don't see this scratching the walls..

actualy, this exact same thing happened in TopGear UK where they were driving a mazda miata cross dessert and one sparkplug blew off

Top Gear : The Three Wise Men Christmas Special - XR-Underground

Hmm perhaps theres room to enlarge the hole and rethread for an m14 or m16 plug?

OR just found this.

http://forum.miata.net/vb/showthread...light=timesert

Neighbor? Not sure I'd touch it since Joe is very right. Next think you know, your bodgy timecert/helicoil job is the reason that the exhaust rusted and fell off, or that their cupholder broke.

That being said, If you do want to do it, just go down to your local flaps and get a sparkplug thread repair kit. It's something like $20 with the correct timecert and tap in it. I did this a couple weeks ago for my brother and his cavalier. Took me about 20 minutes to get all straightened out. I put LOTS of grease on the tap to catch the shavings, then put a vacuum to it.

I think the hardest part would be trying to keep the drill/tap straight with such a deep spark plug bore.

I'm sure it's doable though. Any aluminum shavings that you couldn't get out of the c-chamber will most likely burn up and flow out the exhaust.

Its easier to drill straight with a longer drill.

worked great on my KL back in the day - cheap as it was. Didn't yank head either, just pressurized intake and clocked engine so that air was coming into that cylinder to blow out the shavings as it was being tapped

https://www.miataturbo.net/attachmen...ine=1373421303

i assume is a stock bp motor? not seeing any boost? just heilcoil it for now. take you time and it "should" be fine. IF that doesnt work correctly or it has a pop out issue again, a new head is in order. if the compression is down on the other cylinders a swap might be less of a headache.

Joe makes an awesome point, consider the pros/cons.. and get paid for your time.