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living with ford spark plug blow out problem

Old 04-13-2015, 12:49 PM
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        living with ford spark plug blow out problem

        Old 01-12-2003, 03:55 PM
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        blown plugs - living with fords spark plug blow out problem

        This is a thread I am starting to have a collection of ideas on what to do if you have a spark plug blow out and preventive methods. If you have had a blow out please list the particulars in one of the many threads below:


        Please only post in this thread if you have something to add about what to do about this problem. (we already know FoMoCo sucks)

        If you have blown a plug I'm sure your very angry and if you read the threads above, there are many others that feel the same way you do. But it's time to deal with reality, Ford screwed up on the spark plug head design for the trition engine 1997 to 2003 , Whether you have the old style plug with 3/8" of thread or the new style 3/4" of thread you still only have 5 or 6 threads in the cylinder head holding the plug in. There is a good chance a plug will work it's way loose sometime during the motors lifetime from engine vibration.

        If you want to argue about percentages please do it on one of the threads above there are many arguments there already. It doesn't matter how many engines this happens to ..... It has happened to you and your looking for help. This thread is to inform people about their options if or when it happens to them.

        I made the mistake of paying a ford dealer $1700.00 to remove one head and install one insert... because I wasn't informed.


        One of the easiest: things you can do is listen to your motor when it's idling , prior to blowing my plug I heard a ticking sound like a valve lifter. If you read the threads above you will read that alot. You will also read how the person heard a slight exhaust leak. This sound, is one of the spark plugs worked loose and is vibrating up and down in the threads as the piston sucks and exhausts. There is a good chance that the threads are already slightly damaged. I wouldn't torque this plug to the max spec... maybe something a little less than max.

        you need the correct tools to check your plugs , a deep socket like this:

        Snap-on deep spark plug socket # S9720KA

        Don't use a regular spark plug socket.
        when you are tightening the plugs, if you don't have a extra long socket, the socket with a extension might bind against the spark plug casing wall and you think the plug is tight when it's not.

        and a short handle (clicking type) lb/in torque wrench.
        ( the torque for this plug is 7-14 lb/ft or 84-168 lb/in )

        Always work on a cold engine.

        If you have a blown plug you have the following choices:

        If somebody tells you they can re-thread it, save your money... your setting yourself up to be stranded again in the future. That is totally unreliable.

        a NEW MOTOR, here is a link:


        Just remember you will be installing a new motor with the same poorly designed heads that got you into this mess.

        a STEEL INSERT here is a link to a insert kit:


        the kits cutting tool/counter bore makes the insert flush with the cylinder head and the insert is the bevel seat for the spark plug.

        Heli coils are available but they are not as reliable as a insert.

        Then there is replacing the head. I don't have any links for this but I am sure any ford dealer would be glad to do that for you as the drool drips from his mouth. your talking 3500 to 5000 dollars. And when it's done.. the heads have the same 5 threads holding the plugs in so you have the same potential for a blow out.

        I have never installed the bigserts but they look like the best option to me. I like the way they permanently self lock into the head the first time you install the spark plug. I would like to hear from anyone that has used this product.

        right now we have cylinder heads with the spark plug hole as follows:
        bevel seat, 3/8" of no thread then 3/8" of thread which the old plug with 6 threads screws into.
        so, if and when we blow a plug , when you remove the head we do all 4 holes with a 3/4" long insert like to the ones shown in the link above.
        the insert will be threaded into the 3/8" of no thread area and the 3/8" of the damaged thread area . That would make for a strong reliable mod.

        The installation kit# 5141 costs-> $127.00
        each insert# 51459 costs-> $7.57
        these #'s are for a 1998 ford 5.4L engine.

        *update* here is a link to me installing the big sert in all 8 spark plug holes. (lots of pictures)

        If anyone wants to email me direct --> [email protected]

        GOOD LUCK !

        Last edited by syncmaster; 02-04-2016 at 07:56 AM. Reason: email change
        Old 01-12-2003, 05:46 PM
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        Yeah,yeah this doesn't have to do with your thread which is very valid but can some one explain why the 5.4's blow out plugs more than 4.6's ??????more compression?
        Old 01-12-2003, 08:43 PM
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        Maybe a dumb question that I have yet to get to in the other threads.
        Do you know which Time-Sert kit it is that the truck would use.

        Call it preventive measures, but jsut like I keep a fuel filter, oil filter, etc on the shelf I think I'd be keeping one of these on the shelf as well.

        The kit does look like a nice one, just wanted to know if you recall the sizing, so I can order this.

        Thanks for the write up and the links.


        Why...who knows. Cannot tell between the L and the N/A 5.4, so it is hard to say for sure if it is compression related or not.
        Same with why do 4.6Ls have carbon buildup in the EGR ports, is this less compression ? Got me ???? Still thinking of why either would be the case, I cannot come up with anything even remotely [email protected]'d to state about it
        Old 01-12-2003, 08:45 PM
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        roushfan . if that where the case then lightnings would be blowing plugs left and right and the modified mustang crowd would be having major problems.

        syncmaster - very good information. most higher end aftermarket aluminum heads have inserts. would be neat to compare the plugs, thread count and design with anything from a z-06 vette to a motorcycle to a dragster, see why they live at higher compression and higher cylinder pressure.
        neat fix would be a larger diameter plug that the plug hole could be tapped while on the engine with a tighter designed thread and because it is a larger diameter = more surface contact surface area.
        a self tapping sparkplug? it could only be installed once but if it lasted 90 to 100k miles? i know sounds corny but some people cant come up with $1700.

        part of the beauty of aftermarket alum heads is they can easily be repaired (welded up and re-tapped) is the 5.4 alum of a low quality cast that can't be welded?
        Old 01-13-2003, 03:16 PM
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        hi guys,
        If you viewed this thread earlier I had to change some information about the choice of insert to use , so just re-read the section starting with "a STEEL INSERT here is a link to a insert kit:"
        Here is the link to the insert company:

        I called the company to get prices and info. they suggest you only put in a insert that will keep the motor original.... that is using the 6 thread plug. They actually made a insert just for that, and it is the new link above called "BIGsert" . I guess it's a liability thing. But they say they have sold thousands of them and they work fine.
        I would really like to redesign the head with a fully threaded 3/4" thread steel insert and a washer type spark plug. But I guess they have a point about keeping it original.

        if you look at the chart of the bigsert , I think the insert# 51407 would be a fully threaded 3/4" and a flat washer type plug. I think this would be a perfect fix for the engine. This is a hard choice. To re- design or not ...... I have to think about this.

        Last edited by syncmaster; 09-22-2005 at 04:24 PM.
        Old 01-13-2003, 05:14 PM
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        Originally posted by syncmaster
        ........I would really like to redesign the head with a fully threaded 3/4" thread steel insert and a washer type spark plug. But I guess they have a point about keeping it original.
        That answered my question..thanks ( they never emailed be back as of yet ).

        Why would they want to keep it origional, if it is being fixed, wouldn't it stand to reason that it did not work right in the first place ?

        Wonder if this woudl do the same thing over time then ?
        Old 01-13-2003, 05:54 PM
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        The L's are blowing plugs out left and right !
        Old 01-13-2003, 07:12 PM
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        Location: Sparks, Nevada
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        Hi Guys...

        Ive followed threads on the blown plug issue for sometime now. Althou i havent had this problem, i still think about all those that have.

        Anyone know if the V10 heads are blowing plugs?

        Old 01-14-2003, 12:30 AM
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        Join Date: Jan 2003
        Location: Jacksonville, Fl.
        Posts: 1
        Hello to all.
        I'm new to this forum having purchased a 1997 F-150 Supercab XLT 5.4L last week. The truck has 37,000 mi. and I purchased it from a friend so I know the history of the truck.
        I've been reading all of the threads about the plug blowout problem with great interest and I have a couple of questions and comments.
        I've checked my truck by listening to the engine while it's running and I didn't hear anything out of the ordinary so that's a good sign. I'm planning on checking the torque on the plugs A.S.A.P.

        You state in your post that the max. torque for the plugs as being 176 in/lb. Is this the recommended torque suggestion from Ford?
        Since over-torquing is a possible contributer to the problem, is there a minimum torque or torque range recommendation?
        When you noticed the the ticking, how many miles or time lapsed before the blowout?

        Have any of you found loose sparkplugs while changing plugs during routine maintenance?

        I've been a machinist for the last 30 years and I'd like to share some information on the subject of Helicoils vs inserts.
        I would definately go with Big-sert. The process for installing Helicoils requires using a special ground tap that comes with the Helicoil kit which is usually a spiral pointed tap.
        Spiral pointed taps have straight flutes with the cutting edge of the first few threads ground at an angle to force the chips ahead of the tap. This type of tap will push all of the cuttings into the cylinder which is not a good thing. A better choice would be a spiral fluted tap which have right hand helical flutes with a helix angle. These taps are designed to withdraw chips as they enter the hole.
        Helicoil sells spiral fluted taps but I don't believe they come with the standard kits.
        The standard kits also come with tanged inserts. These tangs must be removed after installation which is usually done by shearing it with a punch which is inserted down through the insert. this tang when removed in this fashion would also end up in the cylinder.
        Helicoil sells tangless inserts but they don't come with the standard kits. If you chose to use Helicoils you will have to be specific about the tap and the inserts when purchasing them.
        Another problem with Helicoils is that they aren't the easiest thing to work with, even with the part you are repairing sitting on a bench in front of you. I've seen many experienced machinists (myself included) mess up a couple of Helicoils attempting to insert them properly. It looks like it would be extremely difficult to do correctly in the cramped area above the rear plugs.
        I agree that the Big-sert looks like a good alternative to Helicoils and the sparkplug kits look like they have all the necessary tools to do a good job, but like syncmaster said, I wouldn't trust the grease to catch all of the chips.
        I hope I haven't been too long winded and again I'd like to say Hello to all, it seems like there is a lot of good folks and information on this forum.
        Old 01-14-2003, 12:54 AM
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        Nice bit of information you have put together. Thanks for the effort and time
        Old 01-14-2003, 02:26 AM
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        I have been reading about this subject a little bit and I have seen that a hissing noise is experienced prior to the plug blowing out. I have experienced a hissing noise on my 5.4 while accelarating. The noise is most noticable right before shift points. For those of you that have blown a plug, have you experienced something similar to what I am describing?
        Old 01-14-2003, 05:51 AM
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        Old timer,
        at the very beginning of this thread you will see links to alot of sad V10 stories. They seem to blow the most, probably because they have the most horsepower and the most engine vibration.

        I said a ticking sound like a lifter , or a slight exaust leak when it's idling. When in doubt re-torque you plugs.

        54 deluxe,
        the torque I have seen on the net is 84-168 lb/in . The over torqueing you read about is probably when people install plugs without a torque wrench. Since this problem is from plugs vibrating loose because the plug only has 6 threads on it and no washer... I would always torque to the max spec unless you think the threads a bad. Thanks for info on heliciols, It's nice getting advice from people who have actually done this work.

        Have any of you found loose sparkplugs while changing plugs during routine maintenance?
        since I didn't know about this problem I never checked my plugs. Ford recommends changing them at 100k miles. I had no problems with my truck and at 90K I brought it into a dealer for a factoy recall (something about gas tank straps) . so since it had 90k I told them to install new plugs. Then 1.5 years and 32k miles later I had a plug blowout. NOW I KNOW ABOUT CHECKING PLUGS! Think about this... with only 6 aluminum threads in the head, if that plug works loose it's gonna vibrate up and down in the threads like a jack hammer everytime the pistion cycles ..... you don't have alot of time before the cylinder head threads are totally machined away. When mine blew and the head was removed I went down to the shop to see it. I expected to at lease see ripped spark plug threads. when I looked at the head, where the spark plug threads were was as smooth as a piston cylinder, at the very top of the thread area one thread was there.. but pushed up. So I figure that when you install the plug , the plug thread goes past the very first cylinder head thread and if it works loose, it will sit there vibrating up and down wearing away all the cylinder head threads except the top one.

        They do have a point about keeping the motor original. It's easy to forget that spark plug #7 is a fully threaded plug and all the rest are the old 6 thread plug. Or you sell it and forget to tell the new owner. I could see where this could be a big problem. Besides the insert company said these inserts work great even though they only have 6 threads because they are 6 steel threads.

        I am wondering is it is possible to buy a re-built motor with these BIGSERTS installed in all spark plug holes. Does anyone know a engine seller/rebuilder that does this ?

        Last edited by syncmaster; 01-15-2003 at 08:38 PM.
        Old 01-14-2003, 07:29 PM
        Join Date: Dec 2000
        Location: Shelton,Wa. USA
        Posts: 28
        I have a 2000 F 150 Shop Manual. This is a shop manual put out by Ford. The manual has 11 lbs ft. for the torque specification. The manual doesn' t say anything about putting an anti- seize on the threads of the Spark Plugs. I does say "Apply Silicon Brake Caliper Grease and Dielectric Compound D7AZ-19A331-A meeting Ford specification ESE-M1C171-A or equivalent to the inside of the coil boots."
        This is the information for the 4.6L (2V) and 5.4L(2V) year 2000 Spark Plugs. I do not know if this correct for other years of these engines.

        Old 01-14-2003, 07:58 PM
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        Hi warren,
        I have a ford 1998 shop manual. It has 7-14 lb/ft. that translates to 84-168 lb/in for the plugs and the same thing about silcone on coil boots.

        Thanks for the input !

        Last edited by syncmaster; 01-16-2003 at 04:24 PM.
        Old 01-15-2003, 01:08 PM
        Join Date: Aug 1999
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        Ahh, throw the torque spec out the window once you use anti-seize; the Ford specs are for a dry install.

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