Spark Plugs - I'm in the middle of nowhere, help!

[Jon]

Ok, so I'm 80 miles from home, and I do know where I'm at, there's just nothing nearby except for Schucks (Kragens).

I had a spark plug come out while I was driving on the freeway today.

It won't thread back in, I tried taking one of the other spark plugs, that won't thread in either. It seems as if the threads are stripped (in the engine, not spark plug), but when I take a look with the flashlight, there are definitely still threads. However, I can drop the spark plug ompletely in without trying to turn it, it just drops all the way down. I am almost positive, the engine's threads are nearly stripped.

I have 80 miles to go. How do I fix this to get my car running again? My first concern is just getting back home (to WA!), my second is looking for a parmanent fix...

So, will some type of thread lock do the trick? I've always had in mind I shoul stay away from that and spark plugs, I don't know why.

I really don't wantto have to deal with this right now! I havea headache and don't know what to do, I've never run into something like this before!

Please help!

Jon

[ventura ace]

Jon,
The good news is that you can probably repair the stripped spark plug threads in the cylinder head with a threaded insert. Kragen may have the insert and the tool to install the insert. To properly install the insert requires some skill and know-how. The bad news is that it is very unlikely that you will find a way to do it on the spot wherever you are. A good mechanic could do this job without removing the head (though it would be better to remove the head), but this good mechanic would prefer to do the job in his shop, and not wherever you are.

So, unless you run accross the miracle mechanic or helpful Fiat enthusiast that has the tools to help you, you probably need to arange to have the vehicle towed somewhere to have it fixed.

Do you have a vehicle tow policy with your auto insurance?

alvon

[TVST*R]

Where is the car? What town are you in?

[Jon]

They'll tow it, but only for ten miles. The roadside assistance I have is basic at best unfortunately.

Thanks for that advice Alvon! I'm defintitely going to have to look into that.

I am in/near Centralia WA

[Mark_vaughn]

I have never heard of anything like that, but my guess is the spark plug was the wrong size to begin with.

What was it like when it blew out?

[So Cal Mark]

I would guess there already was an insert in the head that loosened up. Since you can still see threads in the head, I'd take a chance on getting the thread repair kit and installing it. The kit will come with a tap, installation tool and inserts.

[124cso]

My 1608 had this problem in about 1974 when some mongrel mechanic overdid tightening a plug. They only thread into aluminium and only have to be "light hand snug" not "wound in like hell" otherwise they just wind out the alloy thread, which is what sounds like has happened to yours ?

You may even find your last service mechanic knew he'd started stripping it and opted to say nothing ?
Mine got fixed by filling top of bore with grease (valves closed) & drill & fit a "hellicoil" insert. Bring piston up to TDC to expell grease and any swarf.

may run a bit lumpy & smokey till all grease is burnt but saves the cylinder walls.
Only REAL fix is to strip head, weld up thread face, re-machine & re-thread the plug hole. Insert should last for years but be careful/gentle with that plug.

[Jon]

So I took it into a mechanic, this afternoon he said, I'm sorry but there's nothing I can do. He said it appears someone had tried to do a helicoil a while back and that it was coming to bite me right now. He's telling me I need a new head. Which brings me to my next question, anyone got a new head?

I just pulled up IAP and it looks like they're plum out of stock. Any other suggestions?

[So Cal Mark]

maybe I can help, what year is your engine? Are you looking for a head with cams, ready to install? Emission equipped?

[Jon]

Hey Mark,

Yes, I am looking for something ready to install. Preferrably without the emissions as it will not be a Cali car, and I think there are plenty of people that do need those parts. But, if you have something with emissions, I can always remove it and send those pieces either back to you or to people who need 'em.

The Spider is a '78, early model (I'm assuming since the rear differential/panhard rod is the pre-79 models).

I'll be checking back here before I go to bed in about an hour, as well as throughout the morning tomorrow. I haven't done much engine work for about 3 years now, so I may also be posting and asking questions as well once I get a head!

Thanks for any help you can provide or point me towards Mark. As many have pointed out, you're a big help here on the forum, and I especially appreciate it!

Jon

[ventura ace]

You're mechanic may be accurate about the head being toast -- or he may be biased against helicoils. Opinions vary, but a properly installed steel helicoil is a stronger solution that the original aluminum threads. It puts the same loads on a larger thread: the helicol outer diameter thread to the enlarged aluminum mating thread, and this joint is not intended to be moved, eliminating the steel-on-aluminum wear issues.

Once installed, your steel spark threads are working against the steel insert threads, a stronger combination than steel on the aluminum alloy. Plus you don't have the tendency for galling the threads when putting the plugs in and out over and over again. The only negative issue that I am aware of is the heat transfer coefficent is different, so you may have to run the next heat range plug (hotter or cooler, I don't remember) for the holes with inserts, as compared to the holes without inserts.

Take a look at that head again before you decide to junk it. If the helicoil came out cleanly without ripping the mating threads, it may be saved yet. I have had a helicoil back out on me (on a VW engine), and reinstalled properly with no problems. Don't give up on it unless you are certain.

alvon