The SVT Equivalent of coal

[fullofvenom]

Got a nice present this holiday. Finished a nice Xmas eve dinner with my family and headed back to our house. We got about 10 miles into the drive and something started rapping under the hood. I immediately pulled over, popped the hood and heard the most painful noise I've heard in some time. The front cylinder on the passenger side sounded like it was flopping around. The plug wire looked like it was bulging out every time the stroke came up to the top. I don't know if the plug blew out, the bearing spun or what, but it broke my spirit :cryying:

I'm going to tear it down a little this week to see what I can see, but I'm not too hopeful. I didn't hear any really bad grinding.scraping noise before I shut it off, so with luck, whatever broke didn't cause to much carnage.

Any bets on what broke?

 

[72 fastback]

weird hope it's just a plug?

 

[fullofvenom]

Turns out to be a plug, it popped out of the hole. Looks like the head is stripped. Damn shame.

 

[97 Black Cobra]

Damn that sucks, sorry to hear that.

 

[Cobranator]

Turns out to be a plug, it popped out of the hole. Looks like the head is stripped. Damn shame.

That's surprising. Never heard of this happening to the DOHC engines but it's not uncommon with the SOHC in cars and trucks.Ford is aware of this and there is a TSB out for this problem as well. Did you have your spark plugs changed recently and they weren't tightened enough?

There is a fix for this, though I'm not sure it applies to the Cobra engines.Here's the link.
http://www.timesert.com/html/triton_repair.html

 

[epracmetcon]

Guess its time to upgrade to some 03 heads!!

 

[97SVT#777]

Happened to me last year on two different cylinders. First one didn't mess up the threads but the second did. I had a local shop put an insert in for $200. Seemed everything was okay untill 2 days ago when I changed the plugs. I couldn't get the plug wire back on the plug so I started looking down in the hole and it looks like the plug is kinda sideways. I don't know if the insert is messed up and cocking the plug to the side but it will barely go on. A machine shop can put the insert in for $50, but you have to take the head off. A local shop wanted $1300 just to take the head off and put it back on. Car has run great so far with the insert in, even boosted. Still runs good with the plug wire half way on. Hope some of this helps you.

 

[fullofvenom]

Thanks for the information. I'm going to replace the head. The insert seems like a temporary fix and I'd hate to have another one pop out. I've heard they started putting more thread in the hole some time in 04.

The plugs were not changed recently. Its been about 15000 miles with no issues at all. I've even checked them from time to time. Perhaps there was some weakening of the threads by over torquing the plugs, but I'm pretty sure I kept to specs. The looseness of the plug has nothing to do with it. They don't back out, they pop out, taking the threads with them.

So, now I just have to figure what the hell else I'll need to swap the heads out.

 

[97SVT#777]

Thanks for the information. I'm going to replace the head. The insert seems like a temporary fix and I'd hate to have another one pop out. I've heard they started putting more thread in the hole some time in 04.

The plugs were not changed recently. Its been about 15000 miles with no issues at all. I've even checked them from time to time. Perhaps there was some weakening of the threads by over torquing the plugs, but I'm pretty sure I kept to specs. The looseness of the plug has nothing to do with it. They don't back out, they pop out, taking the threads with them.

So, now I just have to figure what the hell else I'll need to swap the heads out.

Hate to bust your bubble but they DO back out. They don't just pop out of the cylinder head when fully tightened. You have to keep a check on them. Going 15K miles is not keeping a check on them. This is not a rare occurence. If you will do a search you will find a lot of cobras who have had this problem.

 

[98cobra4.6]

You can fix them, why waste your money on new heads?

 

[fullofvenom]

Hate to bust your bubble but they DO back out. They don't just pop out of the cylinder head when fully tightened. You have to keep a check on them. Going 15K miles is not keeping a check on them. This is not a rare occurence. If you will do a search you will find a lot of cobras who have had this problem.

That doesn't make sense. If they backed out before popping out, the bottom threads would still be in the hole, right. If there are four threads and it backed out 1 or 2, there should still be something left in the hole, no? There are no threads left, none.

And, I didn't go 15K without inspecting them, I said its been 15K since the last plug change with checking them from time to time in between.

I know its not THAT uncommon, but I'd hardly say its happened to a lot of cobras. Pickups, explorers....any SOHC seems to be more common.

 

[97SVT#777]

That doesn't make sense. If they backed out before popping out, the bottom threads would still be in the hole, right. If there are four threads and it backed out 1 or 2, there should still be something left in the hole, no? There are no threads left, none.

And, I didn't go 15K without inspecting them, I said its been 15K since the last plug change with checking them from time to time in between.

I know its not THAT uncommon, but I'd hardly say its happened to a lot of cobras. Pickups, explorers....any SOHC seems to be more common.

From what I've read its been more of the SVT vehicles, mainly the lightnings. The first one that came out on me didn't mess a single thread up. I just screwed the spark plug back in and all was well. The second one caught the first thread just enough to not be able to get the plug started. It almost sounds like you had something more serious happen. If it took all the threads, that had to be some serious cylinder pressure and weak (for some reason) threads. I understand if you want to replace the heads, but I know money didn't give me that option and my car has been fine.

 

[Labora]

My friend has been through this on his SOHC GT. Had the head pulled and fixed one plug only to drive it for 2-3 months and have a different plug do the exact same thing. 2nd time around he upgraded to better heads real PITA of a problem the inserts scare me personally and the plug rarely ends up 100% back in the stock position and pointed 100% the right direction. (sure it works but not as good as stock I would imagine) Good luck with the problem.

 

[fullofvenom]

Thanks guys. I'm going to have a closer look at the threads. I'd hate to pull the head off and find that there was a much simpler fix.

There is no way I'd trust the insert for any length of time.

 

[COBRA90GT]

Just out of curiousity, what spark plugs were you running?

 

[fullofvenom]

NGKs

 

[CJK440]

Thanks guys. I'm going to have a closer look at the threads. I'd hate to pull the head off and find that there was a much simpler fix.

There is no way I'd trust the insert for any length of time.

Why?? The insert is better than factory. There is a reason the plugs blow out. Its a major Ford design mistake and shame on them for not owning up to it. The Timeserts are a great concept and since the insert stays put for good, there is no more aluminum to wear. Your plugs now thread into steel. Can't get better than that.

The timesert kits are designed to chase whatever is left of the spark plug hole for a straight installation. If you screw it up of course you will have problems but don't even worry the slightest bit about the inserted spark plug hole if done correctly, worry about the ones that haven't been inserted.

Unless you have another reason to swap heads, its silly to do so just to fix a stripped plug hole. If I have plug blowout on my car, I plan to get the kit and do all 8 holes for good measure. At least you have fairly easy access to the holes unlike the triton truck motors that have 4 holes under the cowl.

Steel thread inserts in an aluminum part is nothing new.

 

[97SVT#777]

NGKs

Both of mine were on NGK TR6's. Makes me wonder......

 

[Toasty]

I doubt its spark plugs guys, this is likely to do with OVERTIGHTENING spark plugs in aluminum heads. A couple of local termy owners blew plugs completely out of their heads under boost. Both times they had recently swapped plugs and used their 'calibrated hands' to tighten the plugs. After costly repairs on both cars, they started using a torque wrench to properly tighten the plugs and all has been well since then.