When to check torque of spark plugs? (engines, Ford, head)
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I replaced spark plugs at my F250 ld 99 with 4.6 engine that is known to blow out spark plugs and threads of aluminum head with it. I used torque wrench, thread chaser, nickel antiseize. I replaced it at 108K. When is time to check torque of spark plugs so they do not get loose? 5K or 10K.
I have never rechecked torque on spark plugs that were properly installed. The only ones I have ever seen back out were either the wrong type of plug or were not torqued enough when installed.
What is the base cause for problems on this particular engine?
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Does not make sense to *re-torque*, if you take into account that spark plugs should always be installed with *NEW* washers, when removed and then re-installed for inspection.
Install without any *aid* with a new washer, finger tight, then torque to the specified torque and leave it alone.
Use the torque wrench to make it *click* once and then leave it alone !
You re-torque, you crush that washer more and more until it does not work as intended !
The specified torque should NOT have completely crushed the *new washer*.
On connections that use a solid flat washer, torque is applied so that the resulting friction will *hold* the connection tight.
A spark plug washer uses the resulting *spring action* of the shape of the washer to hold the plug in place.
What is the base cause for problems on this particular engine?
Only 3 threads in aluminum head. Well known problem and entire industry grow up how to fix it, Timeserts etc. I do not check spark plugs at other cars either.
Torque specs are likely now throw out the window with the addtion of anti-seize as it serves as a lubricant. You can still tighten to the specs but actual force of the plug face/washer to the head has now exceeded the recommended level.
Torque specs are likely now throw out the window with the addtion of anti-seize as it serves as a lubricant. You can still tighten to the specs but actual force of the plug face/washer to the head has now exceeded the recommended level.
Of course with antiseize I count 10-15% less of torque. Nothing new there, it is all across internet.
I’m big fan of antiseize and dielectric grease as it proof it work countless times.
Only 3 threads in aluminum head. Well known problem and entire industry grow up how to fix it, Timeserts etc. I do not check spark plugs at other cars either.
Funny you brought up Timeserts, not a lot of people know that is the only way to go on that repair. Everyones first thing is to use a Heli-coil
Only 3 threads in aluminum head. Well known problem and entire industry grow up how to fix it, Timeserts etc. I do not check spark plugs at other cars either.
Yeah - truth is, with these engines, all you're really doing is lowering the likelihood that the inevitable will happen. It's a poor design. Most of them end up with a helicoil.
So much about spark plugs torque checking.
"Smaller increments can often lead to incorrect readings. For example, it’s almost always a bad idea to take a bolt that has already been tightened to 65 ft-lbs and take it to 70. This is true, and if you find yourself in this situation, you should loosen the bolt and then retighten it to 70 ft-lbs.
Many people think the reason is because a torque wrench isn’t able to measure the 5-pound difference in an already tightened bolt, but this is untrue. The truth is that a bolt that has already been tightened will usually have a breaking point (the amount of pressure that’s required to get it moving again) that’s higher than the amount that it has originally been torque. So, for a bolt that has already been tightened to 65 ft-lbs, the force required to get it moving again could be 5 ft-lbs or more on top of the original 65."
I actually tried to check #1 and it did click even when I set 16 lbft. I know now why.
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