I have a 1999 RV with a F53 chassis.

It has a V10.

I found a torque spec (on a Ford site) for the spark plugs on the web saying 160 - 168 inch lbs.

I then contacted Ford and they said 71 - 106 inch lbs!

So ..... what do I do? Both answers are from Ford but which is right? Does anyone have the correct torque spec for this engine (early single valve V10)?

Also, I want to confirm the gap .... I "think" is should be .052 - .054 or .056

Thanks ..... Mike

 

That is confussing!

I believe to combat the plug spitting issue, Ford upped the torque spec to 160-168 on the earlier V10s.

Just hang tight and some of the V10 faithful will chime in with the accurate info....I'm nothing more than a hearsay speculator

 

The range given is 7-13 ft lbs and not enough. Recently I had a blown plug after 20k at around 14 ft lbs. I would recommend going up to 20-25 ft lbs. Check out the V10 forum and you will see similar results.

Also replace the boots and springs while in there. Denso has a kit on Rock-auto that works well. Stick with Motorcraft or a Denso coil pack too. May want to have one ready for a misfire.

 

NEVER go above 13 ft. lbs. Over tightening stresses the threads and is blamed for causing them to fail. I spent at least 40 hours reading everything I could find on the topic before my first plug change. That was one of the reoccurring theories.


I use a "clicker type" inch/pound wrench and tighten to 144 INCH lbs. (12 ft. lbs. x 12 = 144 in. lbs.) That is twelve times as accurate as a ft. lb. wrench.


My Ford Workshop Manual (published in 2005) calls for 7-12 ft. lbs. It covers the F-53 chassis. I've changed my plugs twice and pulled the second set once to inspect the gap and have never had an issue. I have 210,000 miles on this truck, I bought it new. I am an old wrencher from the iron-head days and it does not seem like enough torque, but I've forced myself to stop there and it works.


Be sure to blow out the plug bores before you pull the plugs. Dust/dirt can damage the threads even if it does not get into the cylinder where it obviously can cause all kinds of damage.


You need to inspect the plug boots. Replace them if they are hardened, discolored or cracked. I cleaned mine with a cloth dampened with WD-40 and coated both tips of the boot and the ring where it seals the top of the bore with high quality dielectric grease.


My Workshop Manual calls for 0.052-0.056 inch gap. The gap will probably burn out to 0.060 inches in 100,000 miles. I try to stay closer to 0.052 for this reason. If you plan on more frequent plug changes the 0.056 gap theoretically should improve mileage, but probably not enough for you to measure.


Take your time, be patient, be deliberate, and good luck!

 

You must have missed reading this one then, you will snap the spark plug off before you strip the threads: https://www.ford-trucks.com/forums/1...ead-heads.html
I have read quite a bit about this as well while I was researching the repair on my 1999 V10 that I received with an ejected plug that had already had a failed repair attempt. This very simple fact is that the threads are damaged when the loose plug is ejected under the force of compression firing it out of the hole like a cannon. And the plugs eject because they are installed too loose.
I recommend the Time Sert repair kit when your loose plugs eject.

 

These people advise going "too tight" too. I went 28 ft lbs

http://www.blownoutsparkplug.com/faqs.htm#Q: Why do you prefer 28-32 foot lbs torque instead of the factory specification

Question #51

 

Were you able to repair those plug threads after the failed attempt you inherited? I've never seen that mentioned before. If so, Kudu's to you! Share the details!


While I use FTE a lot, I'm on and off the forum sporadically. I missed seeing that thread, which was written four years after I did my research and changed my plugs the first time; it was posted about the time I installed my third set of plugs. The thread is interesting, informative, and includes a lot of input by people I very much respect after reading their posts for years. I appreciate your calling it to my attention!


If you read the thread carefully, Krewat points out a number of dynamics that affect plug threads far beyond torqueing them on a cold head that will never experience operating conditions again. You will also note the author of the thread was still using 14 lb. ft. of torque, for the reasons Krewat mentions.


Technically, a torque wrench measures the resistance to the rotational force the wrench applies. Thread "stretch" is extrapolated or approximated from that, since it is virtually impossible to measure accurately outside of a laboratory. Which is why torque specs are used ikn the first place.


Aluminum stretches more than steel and is more brittle. The same increase in torque on an aluminum thread increases the stretch exponentially compared to harder metals. Add the effects of thousands of heating and cooling cycles plus the impact of millions of combustion cycles to over-torqued threads and the resultant metal fatigue allows the plug to blow out.


I agree with the post that said the tapered seat holds the plug from turning. (Its primary function is sealing it.) Because of that it is essential to avoid getting anti-seize on the seat, which may be why some are adamant that you should never use it at all. I do as others on that thread and brush only a very small amount only on the first few threads of the plug.


I agree you can increase the torque, but only slightly! Any use of anti-seize compound, which acts as a lubricant, actually increases the torque, compared to dry measurement. Keep in mind that virtually any compound, even liquid thread locker, reduces the resistance the wrench measures. Thread stretch is a function of how far the plug turns after it seats, puling the threads in the heads towards the seat. Which, by the way, is the same direction the combustion force exerts on them.


I've changed my plugs twice and had the third set out an additional time to check the gap. My truck, as I stated before, is 15 years old and has 210,000 miles on it. That first plug change was over ten years ago. While I appreciate your recommendation for the thread repair kit, I don't expect to need it.


Next weekend, when I change them again, I'll use the 144 inch pound setting on my wrench. Ford had a lot of reasons for specifying it the first place. I have a good history with it.

 

I was able to repair the threads in #2 plug hole after it had plugs blow out twice. I used the Time Sert kit made specifically for Triton engines and followed their instructions. I used a USB scope on a laptop to inspect beforehand, and after each step in the process to be sure it was clean. It took me under an hour start to finish never having used the kit before, including searching for tools in someone else's shop.

I don't know what the previous repair used. Based on everything I read before I bought the Time Sert kit, I suspect that a Heli-Coil brand insert was used. I got the truck with ~96,000 miles on it and the other 9 plugs that were still in it appeared to be the original ones based on their very worn condition. Several were very loose, much less than 14. It is a miracle that only one ejected. Some did not require a wrench on the socket for removal.
So yes, it is possible for the spark plugs installed at a very low torque rating to function without ejecting, but as evidenced by the ejected #2 plug on my V10 it is just a matter of when, not if it will eject.

I don't dispute the science of what you are saying in your previous post. But it is still my contention that the low original torque spec coupled with the 100,000 mile service interval is a recipe for disaster especially on the original spark plugs.

 

Interesting on the Time Sert kit. I'm glad it worked, it seems like it would have been a tough decision after the previous two failures. (And, I'll bet you're glad it was #2 instead of #5!!) Until your previous post I had not heard of Time Sert. Personally, I only know one Triton owner that ever spit plug and the guy had a dealership fix it.


I can't imagine what made Ford decide three, four or even five threads would be OK? But we are the ones who live with it. There would have been a lot fewer problems if they had designed a thickened boss on these heads like the three valve heads have (although I never want the problems those plugs present!)


Both engines would have benefited from eliminating the plug threads that extend into the combustion chamber. I'm sure the engineers were trying to get the spark closer to the center of the charge for better burn control, but not considering carbon buildup they blame for galling the threads is incomplete design work.


I also wonder if the plugs that have ejected were torqued properly at the factory. At the lower end of the published range, which could explain your case, they would only be at 7 lb. ft. or less! I won't ever argue that is enough, Some could have been significantly over tightened too. I've not seen that anyone has ever tried to measure the torque when they removed the plugs, even though there would be a lot of variables to consider if they did, it makes me curious. My originals were all "tight" when I removed them. Mine is a late '01 with P.I. heads so they have one or two more threads than the earlier design.

My response to this problem is to decrease the mileage interval to 55-60,000 miles and stay with 144 in. ft. because I've been successful with it. I mentioned checking the gap on my third set. It was eroded to 0.060 in. at 50K miles. My first set was at 0.065 at 100K. I prefer to stay closer to the factory spec. than 0.060+.

My decision is also influenced by Ford's earlier report that plug failures were caused by over-torqueing, which in many cases makes sense. However, if incorrect torque is the problem, it is a de facto admission that they were not torqued correctly, considering how many factory installed plugs have blown.


I like my V10 so I work around the spark plug problem. I even passed on a good deal on a 6.2L after towing my trailer with it because I prefer low end torque to more horsepower at higher RPM's.

 

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This looks like the real deal. I book marked it. Thanks.

 

I've never had a plug come out...12 -14 ft lbs with a small amount of anti crap...always use the motorcraft oem plugs. change at 80k. IMO.

 

I like this idea. It is just a bit above the factory torque. A little anti-seize and I should be good to go.

I wish I remembered what I did last time ... what ever it was, it worked. I have 40K on the plugs and they seem to have stayed in and I didn't strip any out.

Mike