Hi Y'all,

Being a newbie here and not owning a Ford truck yet (hopefully buying a 2008 V8 5.4L in a few days), I have questions.

I'd like info on the thread on this site referring to the F250 Triton blowing spark plugs and causing fires.

In looking around the web, I found no info at all on Consumer Reports, but some on Consumer Affairs. Any info you can provide (good or bad) on this topic would be much appreciated.

Thank you kindly,
carolinachrissy

 

It happened on older trucks. Ford changed the design and it's no longer a problem.

 

"Consumer Affairs" website is a nest of lawyers. Forget them. There has never been a fire started because of a blown spark plug. Matter of fact, an NHTSA investigation was started a few years back into it, and because the lawyer LIED, they dropped it without going any further into it, and REFUSE to reopen any investigation into the issue.

The 3-valve engines DO NOT HAVE THE ISSUE whatsoever, and as of model-year 2003, even the 2-valve engines got long-thread heads which almost competely eliminated the issue. Except for bad tuneups or waiting WAY too long to do it.

You have nothing to worry about.

 

They don't blow the plugs anymore. But there is a problem with some plugs breaking when they are being changed. The fire danger was due to there having been some cruise control disconnect switch problems. The switches would leak brake fluid and short out the electrical connection. As brake fluid is very flammable that resulted in fires. Ford has recalled vehicles and installed a new wiring harness for the switches. The '08s have had changes to eliminate the hazard. I've posted about the switch problem several times with links to in-depth articles on the subject. Click on my screen name and select "find all posts" I have made to find those posts.

 

I concur with the above, this problem is almost non existant in newer fords. What happened according to my research is the 5.4L is externally the same package as the 4.6L engine. Around 96 or 7 whenever they started putting the 4.6's into the jelly bean F150's and the heads were converted from cast iron to aluminum, however the casting was never 'critically modified' and the 4 or 5 threads used to hold the plugs in (despite the deep seat) made its way on to the aluminum heads. If the casting was solid, it wasn't an issue unless the spark plugs backed themselves out a little bit or were over tightened, the strength of the aluminum just wasn't enough and the plug and coil assembly got blown right off the motor. If i recall I read one account where it even put a dent in the hood. Ford DID correct this around the '03 model year, and hasn't really appeared much except when an average joe treats his truck like it has good old cast iron heads and torques the living **** out of the plugs, then they spit.

The fires in the early super duties and other ford trucks were something with the ABS unit... brake fluid made its way into the electronics and lit up or something. I'm not too knowledgeable about that, but the newest vehicle I ever seen with that problem around the local yards was a 99 PSD F350 SD crew cab dually 4x4. Was a nice truck, now its a nice shell with a pretty green fender.

New trucks seem solid, I'm sure a defect or two will appear sooner or later but nothing like what you're worried about!

 

You can do a search for cruise fires, cruise control fires, Ford fires, all the different variations on google.

 

The 4.6L never had cast iron heads.

 

In the trucks mabe not, my buddy has a T-bird with the 4.6 that looks like cast iron. I was under the impression the early modulars had cast iron, as I said that what I was informed. Could be wrong though, been wrong before and I'll be wrong again... I've seen me do it.

 

The t-birds only had the 4.6L from 1994 through 1997 and they were definitely all aluminum heads. Sure it wasn't a 3.8?

 

Great info, gentlemen. Thanks for the info. Very helpful.

carolinachrissy

 

I know its a 4.6, i had the joy of changing the alternator on it however, if there was never cast iron heads it would just be poor design on ford's behalf on the early models. If that is the case, I want to know what on earth the design team was thinking! I mean, they have a really deep seat for the plugs there is plenty of room to thicken the thread area.

I mean, I've taken several metallurgy classes and manufacturing classes, there is no reason for that design unless they were intending to manufacture out of iron or just had a brain fart? Aluminum is a great material, but a little on the softer side. Oh well, I've learned something new and stand corrected.

Thanks Krewat, FTE has yet again enlightened me

 

What's very weird is that the early 4.6's had NO problems with this issue. My '96 t-bird, and my '97 cougar, no issues with plugs. Of course, I DID recognize that they need to be maintained, and 100K mile tuneup interval was CRAZY for leaving iron plugs in aluminum heads that long.

I still have a suspicion that it was all in the factory installation of the plugs. For some reason, Ford changed the torque-down procedure AND created an "alignment feature" whatever that means, to help the plugs go in correctly at the factory.

I think it was done correctly at first, and then someone's bright idea screwed up the process. I mean, how many Crown Vic's are running around without blowing a plug?

Another thing, the 5.4L and the V10 are a longer stroke, creating more pressure against that plug. Less chance of it happening with the 4.6L in the first place.

Maybe they just stretched the design parameters a little too far ...

 

I remember reading in an Engine Masters magazine the history of the 4.6L (horsepower figures is for the Mustang, I dont have the F-series figures):

The first generation 1994-98 4.6L 2V had one version of heads (215 hp). Then they changed the combustion chambers for the 1999-2004 2V heads (260 hp). Then changed it again to 3V on the 2005-???? (292-300 hp), with the 5.4L being rated the same hp but with more torque. There were 4V variations on special high output models.

 

Yup, that sounds about right. And don't forget, the 4.6L made it's debut in 1991

 

So are the 4.6L DOHC heads a direct interchange on our 5.4's? I'm not sure whether the Lightning's had a plug spit problem or not, but if that was a 5.4SC in there, I would love to see if those had a plug problem. If they never did, it would confirm Krewat's hypothesis of stretching the design to far. I don't have the figures in front of me, but for the forced induction motors they usually have a significantly lower compression ratio.

Thinking about it, Krewat's point about stroke makes a lot of sense, if a cylinder has more volume on the same compression ratio, the pressure exerted on the head would be substansially more than in a 4.6.

Hmmm... sounds to me like someone got lazy up at ford and never thought the consequences of a stroker thru!