Spark Plug TQ Recommendations

[crzyhrse99]

Just wondering the tq recommendations for spark plugs. i looked in my haynes manual and didnt find any, i recall reading on here that it was 7-11 ft/lbs, but have searched and couldnt back it up. I want to change my plugs tomorrow w autolite 764 and i want to do it right, have heard too many horror stories about the plugs backing out.

 

[steveb24]

just turn them in with your hand, -an extension over the plug till its snug

 

[MBDiagMan]

I am not one to use a torque wrench on much of anything except head bolts, rod bolts, main bolts, wheel bolts and various other critical pieces that truly should be torqued. Spark plugs in Mod motors are an exception, however.

This is an area where Ford came up short. On some engines there are only 3 1/2 threads holding in these plugs.

Remove them carefully! Let the engine cool overnight if practical and CERTAINLY do not loosen a plug until the engine has cooled off for at least an hour. This drastically reduces your chance of pulling threads. After removing the COP, blow out the hole around the plug to remove any debris, then loosen them carefully. If the plugs have gone no more than 50 or 60 thousand miles there will be no problem. If they have gone much farther than that, due to the number of heat cycles there is a chance of stripping the threads.

When replacing them, use ONLY the CORRECT Motorcraft platinum plug. Coat them with a VERY light coat of Copper Based anti-sieze compound and torque them to about 13 to 17 ft-lbs. I torque them to 13.

Many plug threads have been lost on Mod motors and the consequences are SERIOUS. The only way to safely rethread is to remove the head.

If you are serious, follow my procedure and don't let them go no longer than 60,000 miles at the most. The plugs are really good for much longer, but leaving them in place any longer than this is asking for serious problems. Yes these plugs are expensive, $60 or more at the dealer and $35 or so at a discount auto supply, but this is CHEAP insurance compared to R&R of a head or two.

Good luck.

 

[fastback brian]

Well I can say that you have no control over if the plug threads live or die. Ive replaced countless number of heads becuase of bad castings. Hot or cold, high milage or low milage there just isnt a set pattern for blown spark plugs. I can say 95 percent of the heads I replaced are the windsor heads, not beacuse of the castings just because every 5.4 and 6.8 have them. Not too many 4.6's blow spark plugs but it does happen. You should torque the plugs to 11-13 ft-lb, lube is not reccomended and not needed but if it makes you feel better a drop of engine oil on the threads will not hurt much. It is also a good idea to use dielectric grease on the plug boots, new boots are reccomended if they are cracked or fit loose in the hole.

 

[MBDiagMan]

Yes, I forgot to mention the dielectric grease on the boots. If you ask for "tuneup grease" at the auto supply they will know what you are asking for.

And yes, the 4.6 is not near as bad about losing plug threads as is the 5.4. I don't know about the new 3 Valve heads though.

I do beg to differ about dry threads. If you use anything on the threads ONLY use Copper based anti-sieze compound and ONLY use a VERY thin coat. The reason for the copper based is for heat transfer. That is the only way I will put them in.

BTW, to a point I agree that you have no control over whether the threads live or die EXCEPT that if you will let the engine cool until it is as cool as it can get, you will have a greater chance of removing the plugs with no trouble. Due to the differing expansion rates of the spark plug metal and the aluminum head, they will be more apt to come out okay if the engine is cold.

 

[san~man]

I lost 2 heads on my 4.6, mind you. And I didn't even install the plugs either.

 

[SigmaPride]

I have replaced mine twice with 764's and no issues. Put them in by hand until they stop and then I torque to 13 ft/lb with NO anti-seize. I change them each year or so...I'll probably go 2 years this time.

 

[the98stang]

torque them to 11 pounds with anti seize. Anything less and they'll back out from the heads. Check the plugs every month too.

 

[nwapache]

DO NOT PUT ANTI-SEIZE ON YOUR PLUGS!!!!! I spoke to TIM at MPH after blowing out one of my plugs a few weeks back and the first thing he told me was DO NOT PUT ANTI-SEIZE ON YOUR PLUGS!!!!!! 11-12lbs torque.

 

[MBDiagMan]

So, does this Tim guy offer a REASON that anti-sieze should not be used?

I have used a THIN coat of COPPER based anti-sieze on so many mod motor spark plugs that I probably should have copper tone fingers and I have never had any problems.

Using a HEAVY coat of it, getting it beyond the threads where it makes it into the cylinder or using non copper based stuff is a bad idea. Most anything can be bad if used improperly.

 

[nwapache]

This tim guy owns a little shop in GA and builds the occasional motor or two...not sure if you've heard of it or not...Modular Powerhouse?!

 

[the98stang]

DO NOT PUT ANTI-SEIZE ON YOUR PLUGS!!!!! I spoke to TIM at MPH after blowing out one of my plugs a few weeks back and the first thing he told me was DO NOT PUT ANTI-SEIZE ON YOUR PLUGS!!!!!! 11-12lbs torque.

Sorry bud but I trust my Haynes book over Tim's opinion

A LITTLE bit of anti-seize won't hurt any...

Now if your gooping that sh1t on there, it COULD be a problem...

 

[the98stang]

This tim guy owns a little shop in GA and builds the occasional motor or two...not sure if you've heard of it or not...Modular Powerhouse?!

Still not a good explaination of why it shouldn't be used

 

[jstreet0204]

Explanations for NOT using anti seize on the plugs.
1. supposedly, the torque specs for the plugs are dry specs. Adding anti-seize can act as a lubricant and allow over tightening of the plugs.
2. New plugs are already coated to prevent seizing, but this is only good for one use.

I personally don't use anti-sieze and have had no problems "Knock on wood". Some use it and don't have problems.

 

[Gearbanger 101]

And yes, the 4.6 is not near as bad about losing plug threads as is the 5.4.

Same heads.

 

[Dan_Soprano]

1. supposedly, the torque specs for the plugs are dry specs. Adding anti-seize can act as a lubricant and allow over tightening of the plugs.

this is true. I don't use it. Then again, I change plugs pretty often.

 

[MBDiagMan]

Same heads.

Not all 5.4's use the same heads as the 4.6. I'm telling you that the 5.4's more commonly experience the spark plug thread problem. Talk to most anyone that sees them come through their shop and I'm sure that they will confirm this.


For those who are getting all wrapped around the axle over whether or not to use anti-sieze....... relative to other considerations regarding spark plug changing it is a non-issue.

The most important considerations in keeping healthy spark plug threads are:

o Don't leave them in too long. Many Ford maintenance manuals indicate 100,000 mile intervals, don't take a chance on stretching them past about 60,000. The more heat cycles they see, the more likely you will have problems when removing them.

o Remove them when the engine is DEAD COLD. Due to the differing expansion rates of the plugs and the aluminum heads, they are not as likely to have trouble coming out while the engine is cold.

o USE A TORQUE WRENCH and set it to 13 foot pounds. I've been changing spark plugs for 50 years and the first engine I ever used a torque wrench on a spark plug was a mod Ford. It is worth the effort.

These are the most important issues. If you will follow these three things, then anti sieze is merely a detail. That said, you won't catch me screwing a single plug into a mod motor without a VERY LIGHT coat of COPPER based anti sieze on the THREADS ONLY.

Good luck.