Blown Spark Plugs - A Very Very Short Pictorial

[ledzilla]

I was rumaging through my tools this weekend when I came across a momento of bad things I keep around. The first of two spark plugs that shot out of the driver side head...

http://uploads.tapatalk-cdn.com/20160329/6d7fac9995c752f8456fcb9b651ff8 d0.jpg

In case any of you out there have been fortunate enough to not have this happen, this is I think a worse case scenario. The only clue I had was a ticking sound I couldn't locate. Must have been driving like that for weeks. By time I found the problem, as you can see, the insulator had shattered and other pieces of the plug had disappeared. It also caused serious damage to the head and I suspect some damage to the cylinder wall. Ever since, my oil gets dark in about 1k-2k miles (used to still look nice clean until about 4k miles), and it will lose about 1/4 quart of oil from time to time, seemingly from mostly city driving. I can only imagine the damage on the inside from the porcelain and metal that fell into the motor.

My local shop at the time did a helicoil and gave me maybe six months before it failed. That was in 2008-2009. At least I caught the second right away, and managed to limp the car down the street to a nearby Ford dealer that still does work on the MM to this day. Another helicoil done.


So let this be a lesson to others not to overtorque your spark plugs.

[mremington]

Just had this happen last week! Same thing, ticking sound I thought was the injectors would come and go, then just kept on ticking the last few months. A few very random misfires and one day the whole car shook and sounded like it threw a rod when I limped it home. Sounded REALLY awful. The plug had shot up into the coil boot. Luckily no spark plug pieces fell into the engine. Did the heli-coil thing and so far its been solid. Martyo helped guide me through the whole process, along with some advice from a few guys here, which was a big help. How long has the second heli-coil been in? Have you been able to change the plug in that cylinder again?

[ledzilla]

The second one went in either during the fall of 2010 or spring of 2011. I haven't tried changing plugs since before either helicoil, but I ordered some new ones from RockAuto I should be getting this week, and I'll be seeing how replacing them goes.

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[RubberCtyRauder]

Use a Timesert rather than helicoil next time, they are stronger

[ledzilla]

I didn't do the work myself. Either time. First one was done by a shop my family's been using since the 80's, the second done by a Ford dealer I use regularly for servicing that happened to be about a mile down the road from me at the moment.

What I'd prefer to do is get the engine rebuilt using 2004 heads instead of the 2003 heads it currently has. And I actually have a couple torque wrenches now, so this time I won't overtorque and damage the threads when I put in the new spark plugs.

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[Zack]

I didn't do the work myself. Either time. First one was done by a shop my family's been using since the 80's, the second done by a Ford dealer I use regularly for servicing that happened to be about a mile down the road from me at the moment.

What I'd prefer to do is get the engine rebuilt using 2004 heads instead of the 2003 heads it currently has. And I actually have a couple torque wrenches now, so this time I won't overtorque and damage the threads when I put in the new spark plugs.

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It's cheaper to have timeserts installed into your 03 4 thread heads.
Converts them to 9 threads

[Mr. Man]

Are the failures happening on replacement plugs or does this also happen on the STAP installed plugs as well?

[ledzilla]

It's cheaper to have timeserts installed into your 03 4 thread heads.
Converts them to 9 threads
I don't doubt it, but I still have no idea if there was any damage done to the head I haven't seen when the first one blew. Chances are that I'm still left with only pricey options on that head. Passenger side should be just fine, though.

Question... If you've had a couple helicoils done, can you have them redone with timeserts?

[ledzilla]

Are the failures happening on replacement plugs or does this also happen on the STAP installed plugs as well?
From what I've seen, I think it's only happened after plugs have been replaced. Mostly from the new plugs being overtorqued on install.

[RubberCtyRauder]

Yes, they make an oversize timesert for previously used helicoil

[ledzilla]

Yes, they make an oversize timesert for previously used helicoil
Guess at some point I ought to score some timeserts and find someone willing to do the installation. I don't trust myself with doing that kind of work. At any rate, though, it's nice knowing that the work done so far has held. But it still all needs to he taken apart to investigate what damage was done. I'm sure that first one to go needs to be honed and get new rings.

[fastblackmerc]

Guess at some point I ought to score some timeserts and find someone willing to do the installation. I don't trust myself with doing that kind of work. At any rate, though, it's nice knowing that the work done so far has held. But it still all needs to he taken apart to investigate what damage was done. I'm sure that first one to go needs to be honed and get new rings.

Depending on the miles I'd be pulling the engine and doing a rebuild.

Just my :twocents:

[ledzilla]

With a little under 140K miles, I normally wouldn't concern myself about getting a rebuild. But there's obvious damage necessitating it. However, at this time I have neither the skills or equipment to do it myself, nor the funding to pay someone to get it done. As long as everything is working, though, and I don't have any more plugs shoot out, I'm not that worried about getting it done. I mostly just wanted this to be a precautionary tale of what could happen. I wish I would have known then what I know now, so that I could have been better prepared for doing a tune up on aluminum heads. Got pretty comfortable on my old cast iron 5.0L.

[xopher]

This weekend I belched out my 2nd plug on the driver's side. I finally dropped the dime on the Time-Sert kit and will be doing the whole driver's side bank.

Their website says you should turn the motor so the valves are closed and the piston is all the way at the bottom of the stroke and you can tell by putting your finger on the spark plug hole and stopping when you can't feel suction any more. Well, unless my finger grows a few inches, that won't be an option. How can I turn my motor until the valves are closed and the piston is safely out of the way?

Also, any Time-Sert tips from veterans are appreciated.

[Ourobos]

You could shine a light down and see where the piston is at easily.

[RF Overlord]

Are the failures happening on replacement plugs or does this also happen on the STAP installed plugs as well?


From what I've seen, I think it's only happened after plugs have been replaced. Mostly from the new plugs being overtorqued on install.This.

Although it's best to use a torque wrench on spark plugs in ANY car, some are more forgiving...like my '68 Buick. Engines with aluminium heads should ALWAYS use a torque wrench.

[hotford]

Same thing happen to my freash built motor with less than 500 miles, check the cylinder with a boreascope right into the chamber,lucky no damage some of the debris went out the exhaust, installed a time insert and back on the road, next day!

[ledzilla]

This.

Although it's best to use a torque wrench on spark plugs in ANY car, some are more forgiving...like my '68 Buick. Engines with aluminium heads should ALWAYS use a torque wrench.
The cast iron heads in the 5.0L my old Town Car had were very forgiving, and only needed to be snugged up and they were good to go until the next tune up. I used the same thinking with the first tune up on this aluminum 4.6L and lost two plugs. One of those things I wish someone has told me about beforehand. Live and learn, man.

However, my friend inherited her grandfather's old late 80's Cavalier. That motor was not forgiving. I helped do a tune up, but when her grandfather last did one he had tightened the plugs so much that removing them severely damaged the threads. Fortunately they held for the next couple months before the car got totalled in a wreck.

[ledzilla]

Same thing happen to my freash built motor with less than 500 miles, check the cylinder with a boreascope right into the chamber,lucky no damage some of the debris went out the exhaust, installed a time insert and back on the road, next day!
I managed to pick up a Droid compatible USB endoscope recently for $27. Looking forward to using it to see how badly the one cylinder was damaged. Well, maybe looking forward isn't completely correct, but you know what I mean.

[xopher]

I'm doing a Timesert 5553 on at least one cylinder tonight. How bad do I need to worry about turning the engine so the valves are out of the way? Are they really within a few millimeters of the spark plug hole?

[TiTo35]

I had this happen to me driving on the beltway...scared the **** out of me! Took it to my mechanic and he told me to just pray on it...lol! That was about 2 years ago...and she is running fine to me...

[JimP]

I managed to pick up a Droid compatible USB endoscope recently for $27. Looking forward to using it to see how badly the one cylinder was damaged. Well, maybe looking forward isn't completely correct, but you know what I mean.

Great item to own, I don't know how I never did without one of these before. I've had it 2 weeks and have used it half a dozen times already on friend's cars.

[Chayton]

funny you should mention... the crown vic sport I bought always ran rough until 2 weeks ago it blew the sparkplug out... on further investigation the previous owner had put a helicoil in on that cylinder. I dont think it was done right, the car always ran rough(air was escaping past the helicoil) Where can I buy the RIGHT helicoil and or timesert kit? I need to fix it asap it is my dd.. please halp :(

[JustRight]

Luckily no spark plug pieces fell into the engine.

Just put the pedal to the floor and hold it on the rev limiter for a few minutes and all the junk will blow out the exhaust. I actually had a 5 year Ford technician tell me this once. I sure hope he got into another line of work----maybe fries or such.

I was so very thrilled to discover no one had changed/screwed up my plugs yet. 155 in lbs with anti-seize compound and life is good on that subject for now.