Have you guys ever heard of a spark plug being blown out of a head?

Discussion in 'SN95 4.6L Mustang Tech' started by jayssilver4.6, Jan 10, 2006.

  1. I am a ford tech and I have never seen a plug on a modern ford aluminum head weld itself to the head. That might have been a issue back in the early days of aluminum heads, but engineers and metallurgists know how to keep the two metals from having a chemical reaction.. thats what used to cause those issues of corrosion and welding..

    As far as I can tell Ford does not use anti-seize on the spark plugs on any engine they produce today, and they have never recommended us to use it.

    The cause of most of the plugs getting launched out of the heads is a combination of

    1. poor design of the head, not enough clamping force can be applied to the small number of threads in a soft metal like aluminum..

    2. insufficient or excessive torquing of the plugs..

    the combination of these two things is what causes this problem.
  2. some people talk about getting ported heads to solve the problem. i got ported heads but the problem is now worse.

    they are the same pi heads just ported. i spent a ton of money and now im super scared to blow a plug and ruin the ported heads. that would be such a waste.

    i need to find a way to make sure they stay in. more so when im forcing 15 psi of boost.

    i was going to call fox lake and ask them about this:shrug:
  3. I forgot to ALSO ask about the 99-04 Mustang heads and spark plugs that are in the V6 3.8 liter engines. Do the spark plugs on the 99-04 3.8 liter V6 Mustang engines have the same exact problem just like the spark plugs and heads which are on the 4.6 Liter V8 99-04 Mustang engines? Do the heads on the 99-04 Mustang V6 engines have spark plug threads which can cause the spark plugs to blow out?
    Are the heads on the 99-04 3.8 liter V6 Mustang engines ALSO Aluminum like the heads on the 99-04 4.6 liter Mustang GT engines?
  4. Well, does ANYONE know the answer to the post above that I made about the heads and the spark plugs in the 99-04 Mustang 3.8 Liter V6 engine? Do they have the same problems like the 99-04 GT V8 engines?

  5. The 3.8 heads are aluminum but I have never heard of a 3.8 blowing plugs out.. somebody cross threaded that plug on you and damaged the threads or they left it finger tight.
  6. I can't find the thread, but there's a class action suit against Ford for the design of the heads. There's not enough thread engagement and it's well known they blow plugs out.
  7. That would be nice if something came out of it. I agree there's not enough thread engagement.

    I've blown a plug out ~3 months ago :notnice: , stock heads, but I did change my plugs maybe 3-4 months prior. Luckily I was going pretty slow when it happened. My shop put the plug back in since the plug wasn't stripped...so i wait for it to happen again if it does, then new heads.
  8. Dont know if it has been stated, but I have read that Ford added more threads to the spark plugs starting mid-2002. So if your care is before that date, technically it could happen (It did to me) Hope this helps somebody.
  9. If Ford added more threads in '02, it didn't do much good. My stock '03 needed it's first spark plug thread insert at less than 5,000 miles.
  10. I have seen several blown plugs on mod motors, but I have NEVER seen one blown that I PERSONALLY put in.

    Yes, this is INDEED less than a perfect engineering design, BUT you can completely avoid having this problem with your own engine if you will keep your head out of your rear end and pay attention to what you are doing.

    There have been VOLUMES written about this. Five minutes worth of reading before touching the plugs on one of these engines will almost totally guarantee that you will have no trouble in this area.

    If it is not already there, the correct plug changing procedure should be "stickied" at the top of these forums.

    So, for the umpteenth time, here it is again:

    Remove the COPS or plug boots whichever apply to your engine.

    Blow out the spark plug wells with compressed air to remove debris.

    Remove the plugs, an extension that locks to your spark plug socket is handy for this.

    Use the CORRECT Motorcraft plug for your engine and gap to spec.

    This step is controversial, but I have always used a LIGHT coat of COPPER BASED anti-sieze compound to the THREADS ONLY, never let it on the end of the plug.

    Start the plug into place using only the extension until you KNOW that it is threading in properly.

    Torque it WITH A TORQUE WRENCH to 13 foot/lbs. (156 inch/lbs.)

    If you will follow the above procedure you have a 99.99999999% guarantee of never having problems.
  11. What about medium strength loc-tite?
  12. You don't want to use that on your sparkplugs. Just torque them down properly, and check them every so often.
  13. DO NOT USE LOCTITE!!!!!!!!!!111

  14. been there already, a couple of years ago I tried this out both on my own car and some parts trucks with 5.4's for a little while my dealer wanted us to use loctite on them.

    the problem is the removable loctite at least the compound I tried could not hold up to the heat, and might act as a lube making the problem worse, and the high strength permanent stuff is just way too strong, sure the plugs will not loosen on you but they are a **** to get out and could possibly damage the threads int he head. Maybe someday they will come up with a compound that would work but as of now there is none that i am aware of.

    I find the recommended torque with NO anti seize works best.

    modern aluminum heads don't suffer from the same problems of corrosion caused by different metals. this due to more experience with aluminum heads. engineering and metallurgy have solved that problem, so the anti seize is not needed.
  15. No anti sieze will work okay as long as the plugs don't stay in the engine too long. Don't leave them in there longer than 50,000 miles if put up dry. It's best not to leave them in there over 50,000 miles REGARDLESS. If you can't afford new plugs, remove them, gap them and replace them. The gaps will be pretty wide by that mileage.

    It is the heat cycling that will eventually freeze the plugs to the threads.

    I have replaced a zillion mod motor plugs with a VERY LIGHT coat of COPPER BASED anti-sieze on the thread surface ONLY. Do not let it be beyond the threads. I have NEVER had a problem with these.

    There are several other things that go along with this though; remove plugs when engine is DEAD COLD, blow out the wells before removing the plugs, use the Motorcraft platinum replacements only, torque them to 13 ft/lbs.

    I never used a torque wrench on a spark plug in my life with no trouble UNTIL the mod motors came out. Don't even DREAM of putting them in one of these engines without using a torque wrench.

  16. I agree about the tourqe wrench, everybody on here should go and buy a 3/8 tourqe wrench, you don't need a fancy one, just a sears one will do the trick.

    Also as posted above it is important to blow all the dirt out of the plug wells before you remove the plugs. and as far as the antiseize goes, My only concern is that it could act as a lube when the engine is hot. If you are going to us eit use the high temp stuff.

    Also remember to check the tourqe on them every 5 thousand miles or so.. I do it on my car every other oil change. no need to remove the plugs just set your tourqe wrench and go over each of them.
  17. I know this is an old thread, but I just went to www.blownoutsparkplug.com

    That guy says 28-32 ft lbs is what him and 10 Ford Master Mech. came up with. They said they tested a head torquing a plug to 100ft lbs without failure.
  18. I check my 04 GT with a 3/8 torque wrench set to 13 ftlbs and all 8 plugs were tight.

    34G on the clock.
  19. Anyone used blownoutsparkplug.com?

    Has anyone used blownoutsparkplug.com to repair a blown out spark plug?

    I had #6 blow out yesterday on my '01 GT. The threads are now shot.

    I am having a local shop and the Ford dealer quote fixing it, but I really don't want to pay $3000+ (the amount I've seen posted on this forum) to replace one head on a 10 year old car.

    I don't have the tools or space to do it myself.

    Any experiences would be appreciated before I make a decision.