Hello,
I recently replaced the plugs on my "new to me", '99 Superduty, it has 105000 miles on it. When I removed the plugs I found that #8 was loose, which made me feel a little sick, so before taking #8 out I tightened it and torqued it to 120 inch pounds. When I removed #8 it did not have aluminum in the threads. So then installed all the plugs and torqued them all to 120 inch pounds. I drove the truck about 50 miles and then rechecked the torque, and #8 was loose again. I was able to removed it and reinstall and torque with no problems, it does not feel stripped. Is there anything I can do before the head gets ruined.
I want to say thanks to everyone, I've been reading this forum for 6 months now and have gotten alot of good info.
Thanks,
Mike

 

Okay, I'm going to state the obvious and hope its worth a try. People frequently do NOT recommend reinstalling the same plug (actually, it the washer) because nowadays the washers are "crushable". In this crushed condition, they exert enough force to keep the plug from coming back out.

However, if you remove, then reinstall, a crushed washer, you don't get the same "locking" effect. Frankly, that's the only thing that comes to mind as to why a plug would vibrate out so quickly, except for the other obvious-but-we-won't-talk-about-them possibilites.

 

Spark plugs on the V10 are tapered-seat, no washers.

If it were me, I'd probably try high-temp loctite (maybe the red stuff, depending on it's specs).

Doesn't sound good. Sounds like the spark plug seat in the head is out-of-round and it's not seating properly and getting the right "clench factor".

If you can, take the plug out and check the hole with an inspection mirror. I did this to all 10 of my holes (besides the one in my head) and they all checked out fine.

Sounds like you might be on your way to a time-sert.

let others here reply, before doing anything like using loc-tite.

 

It may be that your engine is getting ready to spit the plug out. This is a well known problem that requires head replacement.

Others have gotten by with repairing the affected plug hole with something like a heli coil designed for this purpose.

 

Actually according to most of the threads on this the time-serts are much cheaper, relatively easy to do, and last a long time. Besides, what's the harm in trying krewat's Loctite first. Just might work!

 

Vermontmike
Welcome to FTE and the V10 forum

saskdiesel

sir, if you are not in the know on all things V10 or Ford aluminum head modular motors all your post does is spread more myth(s) then good information... our users down here are seeking good, factual and trust-able advice... might I humbly suggest you not contribute in areas you are not familiar with?


I never looked up the torque spec for the 99 but do know that on the 01 and up is 14 foot lbs or 168 inch lbs...

I am thinking 120inch lbs is a little low...

My technique uses a little anti seize, and a two stage torque sequence... all first to 120 (10ftlbs) and after a few minutes of rest at that torque, I final torque to 160 (13+ foot lbs)

I check the next weekend after several heat cold cycles have happened And when engine is at same temp as when I torqued them, (normal outside air temp) not when motor is warm or hot.

Blow out of a steel plug in an aluminum head is rare but can and does happen. Under torque can cause it, maybe, or sometimes... over torque will make it happen most of the time.

There are several repair methods...
Head replacement is most expensive
Weld in cone and cut new threads is second most expensive
Heli coil and Timesert are usually least expensive but can cause problems if not done properly

It is possible to fix a stripped plug thread without removing the head but has risks

At these low torque numbers I never ever use a $12-$29 dollar el-cheapo swinging needle torque wrench... get a good calibrated click style torque wrench where the normal use will be mid scale readings... in this case a 75-300 inch pound torque wrench is more accurate then a 0-150 or a 100-400 both of them require your setting to be at the bottom or top of the range and they are not very accurate at either end of the scale

For torques under 25 foot pounds I always us a inch pound scaled torque wrench (1 foot pound equals 12 inch pounds)

 

I am just going from past experience. I have not had to heli coil a Ford head yet but that may happen. I have seen 5.4's and 6.8's with blown plugs. And it is not "rare" if I've seen my share in the place where I live.

I have also been a journeyman tech for 20 years now and have repaired many ATV's and motorcycle heads in my spare time.
If a plug is loose, and I do not recomend red loctite, it is bad news waiting to happen. Period.
The head may or may not have to come off. I would repair it on the vehicle if it was my truck.
I would not if it was a customers vehicle.

Sorry about interupting your club Fred, didn't know I had to ask your permission before posting.

 

Not to gang up on you, but the first paragraph is at the very least misleading. The second is also misleading. Which is why you got Fred miffed.

Many here do not consider a Timesert a "get by" solution. If you've been reading this forum, lots of people have done the timesert and not had any problems ever.

If it were me, and my V10 blew a plug, and I had the time to do it, I'd remove BOTH heads, and put inserts in every hole. If it were 20 degrees outside, I'd probably do the timesert with the head on the engine.

I mentioned the red loc-tite because it would work for a while, long enough to get it done the RIGHT way. I never meant to say that it would be a permanent solution.

Tech or not, hang around a while and discover what everyone else is saying about this particular problem.

The problem with the Fords is the 60K or 100K mile tuneup interval. Complete head-in-the-sand type of thing. If they were removed, cleaned and re-torqued every 20K miles (with anti-sieze) they'd last forever.

I am also beginning to suspect there is a reason Motorcraft specs zinc-plated (galvanized) plugs for the modulars now. The iron/aluminum interface is the cause of the problem.

 

I totally agree with the plated plugs. If any manufacturer wants to leave the plugs in for 60K then there will definately be some action between dissimilar metals.
But having talked with other techs and some feel that the amount of material, or lack of it, may have something to do with the problem.
Either way all I am saying is that if a plug is working loose it's far from normal.
I sold my diesel and bought an early low mile 6.8 to tow my FJ40 trail rig to and from events.
If I blow a plug out between here and Buffalo SD and I had a chance to repair it on a previous occasion I would have only screwed myself. Thats why I couldn't repair a customers truck like that.
But I want to lurk and learn about my new-to-me gasser rig.

This is what it will be dragging..........

 

saskdiesel

Your screen name, and your statement twice now about plug blow out not being rare and your idea about head must be replaced ($1500-$2900) got a reaction by me NOT about "my club" but rather from the perspective that we have a few trolls that come down here to stir the poo. Most are diesel owners and most like to try and indicate that plug blow out is NOT RARE...

sorry but it is a rare thing. Just ask your self how many Ford Modular motors there are in service. Once you wrap your head around that number (well over 3 million) then do the math times 10 plugs (14% of the 3 million are 6.8L) and times 8 plugs.

The number of robot machined plug holes is over 25 million holes and then there are the over 25 million spark plugs installed the first time by an engine assembler.

That my good friend is a LOT of damned spark plugs...

The failure rate is well under the 3% allowed by the industry.. (note there are no successful law suits against Ford on this in over 10 years of production)

To you and I the 3% of 25 million, though numerically rare is still an issue to be concerned with as a majority of the blow outs are out of warranty.

The problem is UNDER TORQUE or OVER TORQUE or dissimilar metal galvanic action (corrosion of the least noble metal (the aluminum))

The problem can be corrected if it is undertorque... once over torqued there is nothing to do but fix the bad hole.

Sorry if you feel I was a little tough on you but we have no tolerance down here for trolls.

Our primary purpose is to lend a "been there done that" experience based, hand to folks seeking knowledge and advice.

Nice TOY BTW (grin) and congrats on dumping the expensive to fix and feed diesel for one of Fords best motors ever made for a truck!

 

Nope, Im not a troll. All the motors in my driveway and garage seem to have spark plugs at this time.
I am still very fond of diesels though and may pick up another 2LT-II or 2LT-TE JDM Surf for commuting but diesel is $5.40 a gallon where I live.

But since I found a broken exhaust manifold stud on the 6.8 I know what my next chore is. And since this truck has 78 000 kms or 48 000 miles I am going to swap in some fresh plugs.
Hopefully I don't have any loose ones!

 

BS!!!


Welcome aboard, Vermontmike

I would re-torque the plug to proper specs as Fred suggested and re-check. If it's still loose, then I would check the seat as krewat suggested. If that looks good, then I would have a go at trying to do a visual on it. It's hard to tell by looking, but maybe you can see deformation in there if your eyesight is good enough.

Also, if you really want to check thread-mating between the plug hole and plug, you can get some Dykem (sp?) bluing and paint it on the plug to see what shape the threads are in. You'll have to go through the process of re-torquing the plug, but it's worth it to find out for sure. Hopefully it's just a torque problem. Have you calibrated the torqe wrench?

 

Sorry to hear of the exhaust stud... another of the frequent topics here. And my attitude on that is a little tougher against Ford then the plug issue... mating a cast iron part to an aluminum head is not new science and the engineer should be horse whipped for using such puny stud and nut method. I am watching my new motor like a hawk during the warranty period.

My personal history is two V10s and 8 commercial use V10s and none of them (knock on wood) has snapped a exhaust stud. I have helped remove and replace studs on three different Modular motors, 2 5.4s and a 2003 V10

They are predicting we may see gas and diesel down here in the 4-5 dollar range soon... I guess it will be proportionately higher for you as well...

 

Hey Fred, did you notice the exhaust manifolds look like they're stainless? At least they look like it, just a light surface rust on mine, just like the exhaust pipes, still shiny for the most part (and that's after almost 6 years since manufacture and a few VERY salty winters here on Long Island).

Maybe some dummy decided the stainless manifolds were enough and forgot about the studs?

 

Not really sure on the alloy of Steel they are cast from, but your observations are correct they have the best anti rust/corrosion quality I have ever seen in a cast exhaust manifold.

But what ever the alloy, I am certain that the expansion and contraction coefficients are not the same as the aluminum head.

And this may be another case where too tight or too loose on assembly day ends up screwing the owner down the road.

I am a big fan of real close tolerance manufacturing and especially my days yanking the gutz out of gas turbine motors let me see extraordinary examples of what can be done with the right alloys, and perfect machining and assembly. There is no reason the engineers can not apply this science to our internal combustion motors... It is not like any of this is NEW, or "rocket science" fer crying out loud... get with the program butt heads!