chip Q
Senior Member
Joined: Mar 2003
Posts: 739
Likes: 0
From: Houston and Lil ol' England
Plug blowout seems to be completely random.
It happens on stockers, It happens on Modded trucks.
Conversely, there are stockers and supercharged trucks that have never had a problem.
The only sure way to make sure it doesn't happen is to change to the 03 and later heads which have 9 threads in the plug holes rather than the 4 on the earlier heads.
That's probably not an option so I would recommend that you fit new plugs and make sure they are torqued to factory specs.
You may even want to try and have a Ford dealer change the plugs and guarantee the workmanship for peace of mind.
Good luck with the mods.
It happens on stockers, It happens on Modded trucks.
Conversely, there are stockers and supercharged trucks that have never had a problem.
The only sure way to make sure it doesn't happen is to change to the 03 and later heads which have 9 threads in the plug holes rather than the 4 on the earlier heads.
That's probably not an option so I would recommend that you fit new plugs and make sure they are torqued to factory specs.
You may even want to try and have a Ford dealer change the plugs and guarantee the workmanship for peace of mind.
Good luck with the mods.
Senior Member
Joined: Mar 2002
Posts: 4,867
Likes: 0
From: NH
As EnglishAdam pointed out a chip or tune in and of it self will not necessarily cause a spark plug to blow out on older 5.4 heads with the 4 threads for the spark plugs. It does happen on stock motors so it can obviously happen on modified motors (chip, tune) ones as well.
It was a very poor and, obviously, untested design by Ford but we have what we have. Really about the only thing that will prevent a spark plug from being blown out is to check them and check them often. Do not over torque them when tightening or putting in new ones.
I have a 03 L which has the newly designed heads with 8 threads for the spark plugs but I still, as preventative maintenance, periodically check them.
If you hear what sounds like an exhaust leak, ticking ect . (don’t confuse the normal ticking associated with the fuel injectors) it could be a loose spark plug and thus that would be the first thing you would want to check. Many have reported those types of noises prior to having a plug spit out so it seems, at times, there may be some warning.
It was a very poor and, obviously, untested design by Ford but we have what we have. Really about the only thing that will prevent a spark plug from being blown out is to check them and check them often. Do not over torque them when tightening or putting in new ones.
I have a 03 L which has the newly designed heads with 8 threads for the spark plugs but I still, as preventative maintenance, periodically check them.
If you hear what sounds like an exhaust leak, ticking ect . (don’t confuse the normal ticking associated with the fuel injectors) it could be a loose spark plug and thus that would be the first thing you would want to check. Many have reported those types of noises prior to having a plug spit out so it seems, at times, there may be some warning.
Former Sponsor
Joined: Mar 1998
Posts: 13,385
Likes: 4
From: Virginia
Hi svt demon,
There is SOOoo much misinformation on this in general............
And there are some good comments in this thread.
Some quick background on this..............
The fact is, as long as the spark plugs are installed properly to begin with, that is simply not a problem.
Another fact - we've been modifying these Ford modular engines for more performance for as long as they've been made, and not one single engine that we have installed the spark plug on has ever throw a plug - not once.
The problem does NOT come from using chips or performance tuning devices, etc. It does not come from using a supercharger, or raising boost levels on factory-supercharged vehicles like Lightnings - etc., etc. EnglishAdam is absolutely right & makes a good point on that!
But it's not completely random............. the problem is actually caused *primarily* by improper spark plug installation, plain and simple.
Some of these vehicles have the spark plugs installed too tightly from the factory robots screwing them in - and then others (meaning human beings) who change the plugs have tightened them too much - either way, over time and enough heating/cooling and thus expansion & contraction cycles, that causes distortion in the threads - then the spark plug works loose, and finally it launches right thru the coil pack if not caught in time.
Sure, the fact that it's a half-thread design means that it's not going to be as tolerant of improper spark plug installation as a full-thread design - but it's properly tightening the spark plug that is really at the root of it, and there are still engines with the newer 2003 & up full-thread design spitting out spark plugs.
Install the spark plug so that it's hand tight (with the spark plug socket & extension) - then attach the ratchet & give it 1/8th additional turn (and maybe just a tiny scosh more) - along with using a little dab of anti-seize (contrary to what some recommend who say not to use it) is how to properly tighten the plugs in these 2V half-thread modular aluminum cylinder heads.
That is how we have been doing it for all the years that Ford has been making the modular motor, and we've never had an engine we've installed the plugs in spit out a plug - whether the motor was N/A or running 20+ # of boost, running a big shot of nitrous, whether it was making 200 HP or 800+ HP.
Ford went to the full thread design in 2003 for several reasons (not the least of which is it should have always been done), such as the fact that you can get away with more inconsistency (like with robots screwing the plugs in, or a heavy-handed human, etc.) using a full-thread design than you can on a half-thread design. it cut down on the number of warranty claims for thrown plugs - but did not *eliminate* them. Going to a full thread design has NOT completely eliminated plug-throwing, there have STILL been 2003 & later modular engines that have thrown a spark plug out - because the plugs weren't installed properly to begin with.
It's very simple - it's a aluminum cylinder head! So just like with any aluminum cylinder head (only moreso, since it's a half-thread design up thru 2002) - so you have to use caution and proper technique when installing & tightening the spark plugs - do *that* and you won't throw a plug on a healthy cylinder head.
I've been running 20# of boost for 4+ years in my own 2001 Lightning, for example, on those "half-thread" cylinder heads - and I don't plan on installing the thread serts until I change the motor, though it's easy to do. I do that just to illustrate the point.
Of course, I also do not even remotely agree with leaving spark plugs in for 100K miles like the automakers claim - even on a bone-stock vehicle, I just don't agree with running even the best plug in the world more than 50K miles - and less in a high-boost supercharged engine.
I would be the first to agree that having a full-thread design is *better*, absolutely - having 8 threads instead of 4 is certainly preferable. However, that will not eliminate the need to install the spark plugs properly, nor has it eliminated plugs from being thrown in some of those full-thread cylinder heads.
Please feel free to call us if you'd like to go over this in more detail, or would like to go over tuning or other performance modifications for your vehicle, etc.
Good luck with your truck!
There is SOOoo much misinformation on this in general............
And there are some good comments in this thread.
Some quick background on this..............
The fact is, as long as the spark plugs are installed properly to begin with, that is simply not a problem.
Another fact - we've been modifying these Ford modular engines for more performance for as long as they've been made, and not one single engine that we have installed the spark plug on has ever throw a plug - not once.
The problem does NOT come from using chips or performance tuning devices, etc. It does not come from using a supercharger, or raising boost levels on factory-supercharged vehicles like Lightnings - etc., etc. EnglishAdam is absolutely right & makes a good point on that!
But it's not completely random............. the problem is actually caused *primarily* by improper spark plug installation, plain and simple.
Some of these vehicles have the spark plugs installed too tightly from the factory robots screwing them in - and then others (meaning human beings) who change the plugs have tightened them too much - either way, over time and enough heating/cooling and thus expansion & contraction cycles, that causes distortion in the threads - then the spark plug works loose, and finally it launches right thru the coil pack if not caught in time.
Sure, the fact that it's a half-thread design means that it's not going to be as tolerant of improper spark plug installation as a full-thread design - but it's properly tightening the spark plug that is really at the root of it, and there are still engines with the newer 2003 & up full-thread design spitting out spark plugs.
Install the spark plug so that it's hand tight (with the spark plug socket & extension) - then attach the ratchet & give it 1/8th additional turn (and maybe just a tiny scosh more) - along with using a little dab of anti-seize (contrary to what some recommend who say not to use it) is how to properly tighten the plugs in these 2V half-thread modular aluminum cylinder heads.
That is how we have been doing it for all the years that Ford has been making the modular motor, and we've never had an engine we've installed the plugs in spit out a plug - whether the motor was N/A or running 20+ # of boost, running a big shot of nitrous, whether it was making 200 HP or 800+ HP.
Ford went to the full thread design in 2003 for several reasons (not the least of which is it should have always been done), such as the fact that you can get away with more inconsistency (like with robots screwing the plugs in, or a heavy-handed human, etc.) using a full-thread design than you can on a half-thread design. it cut down on the number of warranty claims for thrown plugs - but did not *eliminate* them. Going to a full thread design has NOT completely eliminated plug-throwing, there have STILL been 2003 & later modular engines that have thrown a spark plug out - because the plugs weren't installed properly to begin with.
It's very simple - it's a aluminum cylinder head! So just like with any aluminum cylinder head (only moreso, since it's a half-thread design up thru 2002) - so you have to use caution and proper technique when installing & tightening the spark plugs - do *that* and you won't throw a plug on a healthy cylinder head.
I've been running 20# of boost for 4+ years in my own 2001 Lightning, for example, on those "half-thread" cylinder heads - and I don't plan on installing the thread serts until I change the motor, though it's easy to do. I do that just to illustrate the point.
Of course, I also do not even remotely agree with leaving spark plugs in for 100K miles like the automakers claim - even on a bone-stock vehicle, I just don't agree with running even the best plug in the world more than 50K miles - and less in a high-boost supercharged engine.
I would be the first to agree that having a full-thread design is *better*, absolutely - having 8 threads instead of 4 is certainly preferable. However, that will not eliminate the need to install the spark plugs properly, nor has it eliminated plugs from being thrown in some of those full-thread cylinder heads.
Please feel free to call us if you'd like to go over this in more detail, or would like to go over tuning or other performance modifications for your vehicle, etc.
Good luck with your truck!