Spark blug blew out??? help.

[98Snake03]

Ok. Yesterday I raced an IS-F I downshifted to 2nd at about 50 and coasted down to catch him so we could run....no problems. Then I went to get dinner, then home. Car ran fine.

Then all of a sudden at a stop light, under grandma shifting and acceleration (maybe shifted at 2500) it starts missing.

Long story short, I pulled the coil covers and saw that #2 coil pack was destroyed with the spark plug out of the cylinder and still attached to the coil pack. Came right out...The threads were a little chewed up and the top part of the plug was pressed against the electrode. The electrode wasn't broke or damaged. No oil anywhere.

So I replaced the plug and coil pack, car runs fine. The plug went back in fine after the first two turns and I got it as tight as I could. No smoke at all. Oil pressure is fine too.

Was this a fluke or is there something wrong?

What caused this?

Thanks.

 

[Sonic605hp]

maybe it vibrated loose and finally blew out:shrug:

 

[SVTkel]

Geez, that sucks. Sounds like it is time for you to get those plug inserts I read about a while back on this site.

 

[Juruense]

Well, it sounds like a couple threads were left. Just enough to tighten the plug onto. But there are only four threads there to start with so... yeah...

You really should at least get a borescope and examine the remaining threads and the combustion chamber. Was any materail missing from the plug that could have flown into the chamber?

 

[98Snake03]

Well, it sounds like a couple threads were left. Just enough to tighten the plug onto. But there are only four threads there to start with so... yeah...

You really should at least get a borescope and examine the remaining threads and the combustion chamber. Was any materail missing from the plug that could have flown into the chamber?

If there was it was microscopic and it's already in there....I am changing the oil.

There was a piece of rubber missing from the coil boot but I don't think it got in there...it may have come out when I pulled it out.

I will post some pics.

 

[67couggt]

I had that exact same thing happen on my 2000 gt. I thought I was ok after reinstalling the plug. Blew out again after 6 months. Threads were totally gone this time, I ended up buying the timesert kit http://www.timesert.com and installing to fix the problem.

 

[T-Pain808]

Damn sounds like you where a lucky one
Check them spark plug often. Sounds like you got
lucky and it just backed out!

 

[98Snake03]

I had that exact same thing happen on my 2000 gt. I thought I was ok after reinstalling the plug. Blew out again after 6 months. Threads were totally gone this time, I ended up buying the timesert kit http://www.timesert.com and installing to fix the problem.

how hard was it to install? I'm sure you had to pull the heads???

 

[ShelbyGuy]

The timesert can be done with the valve cover on and the engine in the car. And before the lock&stitch lovers come in with their misinformation, the timesert is an aluminum insert that is cold-rolled to hold it in place.

 

[CobraBob]

This is one of the shortcomings of the stock factory heads which have 4 threads (some '04s got 7 threads). Couple that with frequent changing of plugs and the cross threading risk and you have the potential this very thing happening. The only cure is going the timesert route (least expensive) or install the latest heads which have 7 threads.

 

[Juruense]

This is one of the shortcomings of the stock factory heads which have 4 threads (some '04s got 7 threads). Couple that with frequent changing of plugs and the cross threading risk and you have the potential this very thing happening. The only cure is going the timesert route (least expensive) or install the latest heads which have 7 threads.

There is no such thing as a seven thread head its either four or nine and no 04's came with anything but four threads because the revised head was not available until 2005. Also the blue stripe mean nothing. :beer:

 

[mike302]

If you have the cash get the revised heads from (steve) tousley ford they have me thread on them and are "tick" free

 

[68_GT]

who installed these plugs ? wondering if they were overtightened ? good thing the OP was able to get the car going again but I think it will come back worse as another stated.

 

[CobraBob]

There is no such thing as a seven thread head its either four or nine and no 04's came with anything but four threads because the revised head was not available until 2005. Also the blue stripe mean nothing. :beer:

Oops! Brain fart. You are correct. It is 9, not 7. I should have check my own FAQ page. :lol1:

 

[CobraBob]

There is no such thing as a seven thread head its either four or nine and no 04's came with anything but four threads because the revised head was not available until 2005. Also the blue stripe mean nothing. :beer:

Actually there were some '04s that had 9 thread heads. There was a well documented thread over a year ago with photos to prove it. I saved the photos. Initially everyone was saying "no way". Then a couple of guys checked their heads and it appeared that they did have 9 thread heads. But it wasn't until someone did this test that we were convinced. Check it out. http://stangshiftergaskets.com/2003_2004faqs.htm#_Toc35092462

 

[skaarew04SVT]

my 04 with a build date of feb 04 has the 9 thread heads that is a FACT

 

[98Snake03]

who installed these plugs ? wondering if they were overtightened ? good thing the OP was able to get the car going again but I think it will come back worse as another stated.

I installed the plugs, but almost a full year ago. And after hard driving they have been fine....so I am thinking I didn't tighten them hard enough.

 

[98Snake03]

If you have the cash get the revised heads from (steve) tousley ford they have me thread on them and are "tick" free

I might as well get the GT or FR500 heads...right?

 

[Jimmysidecarr]

There is no such thing as a seven thread head its either four or nine and no 04's came with anything but four threads because the revised head was not available until 2005. Also the blue stripe mean nothing. :beer:

I'm sorry but that is wrong. There was more than one revision to these heads.

My production date is January(Mystichrome run) and I have the 9 thread heads. I am currently under the impression, from talking to 04 owners, that MOST of the 04s had the "more threads heads".

The Jan 05 revision involved the improved guide cooling compared to the 04 heads, but compared to the 03 heads the improvement also included more threads.

So you can see why it would be easy to get the 04s and the 05 Aviator(the last production vehicle to use these heads) revision heads confused.

To the OP, I would look into timeserts, or if you are just rolling in money, put a set of revised replacement heads on.

Don't get the FR500 heads since they are designed, targeted, and better suited for NA applications. In fact the FR500c race cars don't even use them, they use Ford GT heads with a special narrow NA intake to allow the use of a wider 5.4 head on a 4.6 sized block.


If it was me I would do the timeserts.


..

 

[x NOODLES x]

My build date is 03/04. How do I find out if I've got 9 threads??

I'll be replacing my plugs soon.