I guess. Was out in the '07 recently, twice felt a jerk at low speed, light load cruise in OD, guess it's time. 67,xxx miles on OEM plugs, 5.4 3valve. Last year, maybe longer ago, in anticipation, I bought a set of the then replacement plugs, MC SP515 and a Lisle tool (it'll work also on '08 GT if needed ever) and then, seems last year I read about the newer plug, SP546. A buddy said that he thought the SP546 was made with a smaller OD below threads and that he thought they seemed easier to put in, so I ordered a set of them too. Well, this week, maybe next, I'm gonna change them. Curious, I just went downstairs and compared them.

I did not have a oem SP507 out to compare to, but a new SP515 and a new SP546 have same OD, I noticed, there is no sign of heat from any welding on the SP546 body below threads like on the SP515. The SP546 does have a welded lower ground electrode, welded to body and not "made as one" like a SP515.

I tried my new "OEM" brand, really long 9/16 six point plug socket with inside magnet, I saw it went down all the way on the SP515, but it left about half the hex portion exposed on the SP546. Then I saw why. The SP546 upper porcelain is a little taller, the upper end of the center electrode has a lip that will further compress the coil spring in use.

Anyways, guess I'll use the SP546s and just hang onto the SP515s? I hate to put the SP515s in and worry about next time? Weren't but $60 the set. The '08 GT uses something else anyway.

I thought it was maybe of interest.

 

The SP546's are newer.

 

Definitely of interest and I really appreciate your taking the time to provide first hand (NON advertising crapolla') information.

I too had heard (and began to believe) the SP546 had a smaller diameter barrel that extends into the head cavity. That being a change I would have personally recommended LONG AGO instead of the stupid "put anti-sieze on it" service bulletin.

I have long recommended 'REMOVING' the carbon builds up in that cavity with each plug change. https://www.f150online.com/forums/v8...ml#post5159499 . If the 546 isn't different in OD, I'll continue to recommend it - even if the 546 proves less susecptable to breaking on removal. I don't think the breaking is the only problem caused by the carbon deposits comming in contact with the plug tip.

Thanks again

 

Today, I took a few pics and made notes:




The socket with magnet inside




That test fitting drew my attention to coil spring seat / top of plug when SP546 left some of 9/16" flats in view.












Look close, you can see where ground strap is attached, but measured across attachment it remains at same as OD of lower barrel.
I did not have a OEM installed SP507 to compare or measure the lower barrel, so I don't know. After I change them out, I'll try to remember to revisit this thread.

I did find a sheet of specs, http://www.fordinstallersupport.com/...logs/spark.pdf and on P-3 it states a barrel dia for these 507s (what I searched for) as 10.0 mm. which is 0.393701" which is pretty close to the 0.393 - 0.394 range I interpolated it to on the SP515 and SP546 plugs new in box. So "diameter" looks unchanged.

I did note that the sealing taper or step down on the 546 plugs is somehow "more pronounced" but not sure what it means. No bluing. I hope that it means the lower shield is better attached … or maybe one with upper plug body.

 

Neat!

 

^^^^^ Agree

 

Well, I have accumulated all my stuff needed, including new fuel & air filters and stuff to soak old plugs with and … the plugs of course. If the weather co-operates, gonna try get this swap done tomorrow.

 

I bet it'll go fine. I need to look at doing mine again as I'm creeping up on 150K miles and did the first change at 75K or so and didn't have any issues the first time around. I did use the Nickel anti-seize on the plugs per the Ford TSB, so hopefully that makes the chances of an issue even more remote.

 

WELL FUDGE!!

6 came great, #2 broke and the Lisle tool worked great, then #8 way in the back seemed to be coming out great, but it left the porcelain and center electrode in the head with the lower shield.

Found the Lisle 65710 "porcelain puller" … ordered, be here Friday. I have two 3V Fords so I'm OK with it.

It'll sit well with the Lisle 65600 kit.

I'll update this after it's here & done.

Edit added 072519PM:
I used a brass like .40 cal (10mm) gun bore brush working back & forth as 10mm is the design spec on the shield below the threads, but trying to be easy on the brush as I didn't need that stuck in there. I put 7 back in today, all seven threaded by hand turning 3/8 drive receptical on extension, all 7 were easy to thread by twisting extension with fingers only until seated, then I torqued each to 25 ft/lbs. I only put the nickel anti sieze on the lower shield, not on the threads. I think the SP-507 plug came in these trucks, but I put SP-546 in. I had that really long 6 point 9/16" plug socket a couple years. I recently bought a Carbyne 9/16" magnetic Spark Plug Swivel Socket as I didn't yet have one. …....and it was great, I used it mostly. Strong magnet too.

Amazon

Amazon

Tomorrow, that puller should be here and I can do #8.

I had read that the "window" in the shield was smaller on OEM SP-507 plugs, compared to the SP-515 plugs, but it looks same to me. Tips were pretty eroded. What I find interesting about the SP-546 is more pronounced step up at seat area and longer upper porcelain with shorter top to compress spring more. Also SP-546 has no bluing from any weld. Looks more "robust" to me.



EDIT ADDED 07-26-19:

Well, the porcelain puller 65710 arrived late this evening. I took it down to shop to test fit it on a used plug, it grips the top really firm, it snaps on, but then I tried it through the aluminum sleave 65610 that it is used with, was a few thousandths too big after clipping on top of a plug, … so I fired up a belt sander and sanded it around the gripper end segments just a hair at a time until it was a smooth fit with plug gripped. Once you slide this thing into plug well and get it snapped on top of the plug center electrode, then slide the sleave down, it can't expand to let go of plug's top tip. Then just thread the large right hand nut on, and I just turned the nut with my fingers and it lifted the center electrode and porcelain top up out of well.

Then I used the porcelain pusher 65670 to push remains down into lower shield, then used the puller screw 65620 with left hand nut and sleave 65610 to pull the lower shield out of well. Then I put in a new SP-546 with nickel anti sieze on shield only in with hand and socket only ... until seated … then torqued it to 25 ft/lbs, put in coil with dielectric grease on / in boot and hooked coil lead and injector up.

Between steps, I used 1/4" hose on blow gun to blow out each cylinder and plug hole / well several times. As stated earlier, I did button up 1 through 7 yesterday and unplugged #8 injector and moved the truck with the 7 cylinders (slight miss). While I was moving it back to finish today, code P0358 set. I reset & cleared the code, and it stayed off. I guess the computer saw I had no coil there at #8 when moving it.




The addition of the Lisle 65710 to my 65600 kit makes a 65700 kit. Sure am glad I had them, I could not reach into that #8 hole with any pliars. That 65710 was a blessing.


Someday, way before 67,xxx miles, I'll be doing a similar job on wife's '08 GT, I feel better about it now.

 

Dang it, browser closed and opened on me. As I was saying:

Got up, decided to go to the village and to test drive the '07.

I knew from intermittent low speed in OD miss that she needed plugs, I knew that mileage was off too, but I was mildly surprised at how well she ran this morning as I drove to post office and back, guess I had just gotten too used to her running poorly? Only 67,555 miles on her. I saw how gaps had opened up (see pics above).

Runs really well again now.

What amazes me is how easily all 8 of the new SP-546 plugs with just a thin smear of nickel anti sieze on lower barrel (shield) threaded back into and were turned by finger tips on extension until seated (then torqued with TW to 25 ft/lbs) after the protesting some of the OEM SP-507s put up coming out!

Anyway, I'll revisit the plugs when she's up near 120,xxx.

07-28-2019 Edit:

Put about 120 miles on her today, tried many stretches at lower speeds in OD with light throttle and got no misses.
No codes either.
Also, can say for a fact, gas mileage is back up.

 

Good to hear you got it all sorted out. Amazing to see that Ford created an entire product line of tooling for Lisle between spark plugs and exhaust manifold studs, lol.

 

Thank you. I was a bit concerned there at the #8 hole. I still have the new SP-515s, might put them in at 100,xxx even. I went out and looked, if I have issues with the wife's '08 GT, all 8 are super easy to get to, but I think it will take SP-547s now.

I ain't had that second issue …. yet. Don't relish the thought either.

I have a ScanGageII I use, there is a BP station I usually fill up at on the way home from the north, about exactly 14.7 miles. Over the years I've had the SGII, I've made it a habit to pull out, accelerate to 45, reset SGII by plugging out / in, and see how high I can get / keep the MPG AVG from there home. Like a game I play. Used to be I could see 20.5 or even 21.0 on it in this truck as I pulled into my driveway. I had noticed a few months ago, It was not so easy anymore, often only 18.5 at best. I thought maybe still winter gas? Yesterday, with new plugs, same routine, same truck, same gas, same "Me", same road, it read 20.4 when I pulled into driveway. So by the same tools, I restored my mileage.

 

I've been driving around with the exhaust leak from a broken stud for about 6 months. It's sounds like crap, but doesn't affect much. I have the new stud kit, gaskets, and a new manifold ready to go, just dread having to drill out broken studs and the PITA it is to the the passenger manifold out since it's wedged in pretty good with the strut tower. Shop wants $1K in labor to do the job, but I have a hard time letting go of that cash.

 

I had read it's a bear to replace, but seems I read it's much easier removing front wheel and fender liner or something. Anyway, had a leak on the same side exhaust manifold of my seldom used '77 F-150 with 351M, I have a low miles set of manifolds in the basement I've had stashed since in the '80s, but to temporarily fix the leak, I used some exhaust putty stuff …. that was a couple years ago, it is still holding. Go figure.

 

Yeah, will have to remove starter (which I just replaced 6 months ago), wheel/wheel well liner. Some guys even loosen the engine mounts to be able to raise the engine an inch or so on the passenger side to make getting the manifold in/out easier. The driver's side is supposedly quite a bit easier.