Ford 5.4 spark plug problems, need advice

gbail · 02-25-2016, 04:50 PM

I'm looking at possibly buying an older (2005) Ford SMB with the 5.4 that's never had the spark plugs changed yet.

My research showed that changing the plugs on these engines can be costly and problematic and require new after market threaded inserts to be installed to keep the plugs from coming loose and "shooting" out of the 4 thread aluminum heads.

Do any of you have any experience or advice on this subject that you can share with me?

Thx

mgmetalworks · 02-25-2016, 05:00 PM

I purchased the extraction tool off of Amazon in case of problems servicing a 2006 5.4L and we had 5 of 8 plugs break off when trying to take them out. The tool worked great and got every plug out with no problem. This was an F-250 not a van so access is different but the tool itself was worth the money. The head isn't affected and the spark plugs hole threads will be fine as long as tool works as intended (and you're following instructions).

carringb · 02-25-2016, 05:50 PM

Vans don't have the 2-piece spark plugs which can break off.

Really, only major problem (beside difficult access) is be sure they are properly torqued.

gbail · 02-25-2016, 07:20 PM

Yeah, the 3v 5.4 engines have the longer plugs that can break off.

The 2v 5.4's are the ones with the reputation for spark plug "blow outs"
See:
Ford Spark Plug Blowout

So it's this problem I'm seeking your experiences on.

Again, thx

carringb · 02-25-2016, 08:00 PM

Your van will have 8 threads, not 4. That was updated in 2000 and the machining process which sometimes caused weak threads was addressed in 2003. Of course, being aluminum still means its possible to damage them.

Getting enough torque isn't easy. It would be worth buying a small torque wrench if you can swing it. Spec is 10-16 ft-lbs. I've had several spark plugs come loose over the years, normally without issue. I don't have a small enough torque wrench so I just use German torque spec. I'm also paranoid about stripping the threads so maybe I'm under-torqueing them? Anyways... aim for the top end of the spec, price is right rules. I don't recommend using anti-seize, because lubricating the threads requires dropping your torque spec in half, and IMO that may not hold. I've never had one get stuck (mine or my customers cars), and I generally do them every 70-100,000 miles so anti-seize is just unnecessary.

Definitely be sure not so cross-thread them. I use a short piece of oil cooler hose to get them started, making sure I can feel them turn at least 4 turns before I move to the ratchet.

Now, about my loose plugs.... I'm pretty sure there's some harmonic thing going on with the V10. The #10 plug has gone loose 3 times. And #9 plug once. EVERY single times has been after sustained hill climbs with the engine over 5,000 RPM. Normally, the computer won't even allow this. I've raised shift points and the rev limiter so I can pull hills at 5,500 RPM. It makes great power there with my other mods! So... each time with #10 I heard the tick, and and tightened it back up. With #9 I decided to wait until I got home, and 3 hours later it spit the plug. Pulled over, put the plug back in, disconnected fuel to that cylinder, and drove home doing an insert later.

Anyways... if you follow the repair manual, and don't have any mods on your motor, and keep the tuning stock, you shouldn't have any problems!

JWA · 02-26-2016, 03:49 AM

I'm running the 5.4 which for most practical purposes is very, very similar to the V10's, at least as installed in the E-Series.

Like CarringB suggests I use a dedicated torque wrench in the 5-75 ft/lbs range to get the best results at 23 ft/lbs, my choice of plug torque. (FWIW Modular Motors heads have been tested relating to spark plug threads stripping out, up to 90 ft/lbs without any ill effects. I can provide a link to this test as posted over at FTE for anyone interested.)

I do use a nickel-based anti-seize, nothing but the Motorcraft spec'd plug too. Along with my torque I've never had any issues with plugs in just over 100K miles driving on two different vans. BTW I NEVER let the plugs go beyond 50K miles regardless claims they'll last 100K miles.

HTH

arctictraveller · 02-26-2016, 09:07 AM

Quote:

Originally Posted by JWA

BTW I NEVER let the plugs go beyond 50K miles regardless claims they'll last 100K miles. HTH

For what it's worth, my 2001 5.4 got its plugs changed the first time at 105K, and I couldn't detect any difference in mileage or performance after the change. Never the less, 100K is a lot of miles on a set of plugs, and I just feel better knowing there new.

carringb · 02-26-2016, 10:21 AM

Quote:

Originally Posted by JWA

best results at 23 ft/lbs, my choice of plug torque. (FWIW Modular Motors heads have been tested relating to spark plug threads stripping out, up to 90 ft/lbs without any ill effects. I can provide a link to this test as posted over at FTE for anyone interested.)

Interesting. I didn't know that. Actually makes me feel better about cranking them down more next time

After I started running my tuner, that caused the platinum spark plugs to wear out by 60,000 miles. So I've switched to iridium. But, all of my plugs that vibrated out happened about 50k after a change (or once about a week after) so maybe I should just go back to platinums and go to 50k intervals.

JWA · 02-27-2016, 03:50 AM

Quote:

Originally Posted by arctictraveller

For what it's worth, my 2001 5.4 got its plugs changed the first time at 105K, and I couldn't detect any difference in mileage or performance after the change. Never the less, 100K is a lot of miles on a set of plugs, and I just feel better knowing there new.

Yeah there's not a monumental difference or improvement with fresh plugs, with a stock tune I credit the ECM's strategies for that. Regardless from the beginning of my Ford Modular Motor ownership I have never agreed 100K miles on plugs was good or even marginally acceptable. Peace of mind is just one benefit.

Quote:

Originally Posted by carringb

Interesting. I didn't know that. Actually makes me feel better about cranking them down more next time

After I started running my tuner, that caused the platinum spark plugs to wear out by 60,000 miles. So I've switched to iridium. But, all of my plugs that vibrated out happened about 50k after a change (or once about a week after) so maybe I should just go back to platinums and go to 50k intervals.

Again when new to Modular Motors learning recommended torque was 7-14 ft/lbs I was all WTH????

That made absolutely no sense but lucky for me before I changed my first set of plugs I'd found FTE. I swear I devoured every thread or post about spark plugs before finally settling on my own version how to best do this task. In my CP there's no less than 25 thread subscriptions dealing just with plugs.

The thread I mention above is here for anyone interested:Tested for the breaking point on the early 4 spark plug thread heads - Ford Truck Enthusiasts Forums Its eye opening.

**BroncoHauler** · 02-27-2016, 05:20 AM

Do these same guidelines hold true for the 4.6L too? Not SMB related, but my Crown Vic Police Interceptor is coming up on 100k quickly and I'm deciding what to freshen up since it is new-to-me.

Herb