Spark plug torque

[StephenGwyn]

How much torque should I use when installing spark plugs? When I watch mechanics do it they just do it by feel, which I'm sure works fine if you've done it 3000 times.

On a not unrelated note, I broke a spark plug off installing over the weekend. Nothing was left above the hole. Because it I always use anti-sieze and because I let the engine cool off and because I lead a virtuous life, I was able to jam a screw driver into the remaining ring of metal and gently, firmly and steadily back it out. However, I don't want this happening again.

SG

[JOHN COOKSON]

Be sure to chase the threads just in case the spark plug was somewhat cross threaded.(It sure could have been) Did you twist the spark plug in with your fingers before torqueing?
I remember something like tighten the plug until just snug then a extra 1/2 turn if there is a washer or an extra 1/4 turn if there is no washer. You are right. After you do it enough times you will get a feel for the tool you are using.

TRUE GRIT

[romantic comedy]

Sparks plugs dont need much torque. I tighten mine just enough to stay there. Err on the loose side. If they leak a little it is not a big deal and you can retighten if necessary.

I cant give a torque spec, but you can learn to do it by feel also. And yes I have tightened many many plugs.

[StephenGwyn]

Sorry should said that I have a torque wrench and I wan't to know how many ft-lbs to use.

SG

[roadnsky]

The old A4 manual recommended 30 ft lbs of torque
As John said, it's a "feel" thing.
Starting the threads by hand is a must.
See attached...

[JOHN COOKSON]

IMO, despite what the specifications say, 30 pounds of torque is way to much.
IMO,once again, things that will self tighten with use - spark plugs, exhaust flanges come to mind - don't need to be tightened to the max. It only makes their future loosening harder and more likely to break off at the threaded part.

TRUE GRIT

[Bratina]

On that topic, I just ordered a set of Autolite 437 plugs, which David Masury (and others) have long pushed.

I've been running Champion RJ12C plugs, but I'd like to see how these Autolites go, especially given some of the derision for Champion in the 'old tractor' circles.

[roadnsky]

IMO, despite what the specifications say, 30 pounds of torque is way to much.
IMO,once again, things that will self tighten with use - spark plugs, exhaust flanges come to mind - don't need to be tightened to the max. It only makes their future loosening harder and more likely to break off at the threaded part.

Well, I'm just quoting Universal as to the spec. It's certainly not mine.

On that note, somewhere way back when I asked Don about the torque value for the valve cover, he quoted Universal at 30 lbs but suggested he would do it at 20 lbs and no more.

As always on this site for FREE advise.... YMMV

[sastanley]

I think for spark plugs we should be talking in inch/lbs for torque..I don't have a torque wrench that will go low enough in ft/lbs for what I would apply to spark plugs.

My recollection is (didn't we just talk about this?) , half of what John Cookson recommends. 1/4 turn with washer (most of the plugs for this motor have them), or 1/8 turn without washer.

Also keep in mind that the torque applied is related to the length of the handle of your wrench. I use an old school sliding spark plug socket wrench that I found on the boat. The handle is only about 8" long. I keep it as loose as I dare, like RC, while still expecting it to reasonably seal...ALWAYS thread into the hole by hand, even if you need an extension to do so. I recommend just snugging them with a 3/8" drive.

Jerry, let me know how the 437's go. I tried them years ago, but presently am using 'stock' RJ8C's.

[roadnsky]

Jerry, let me know how the 437's go. I tried them years ago, but presently am using 'stock' RJ8C's.

Shawn-
I think it was Bratina that posted he's gonna try the 437's although I've been using them for at least 5 or 6 years since Dave recommended them and I like them.
I also use his suggestion of gapping at .038~040 for a bit hotter burn.

Again, IRMV...

[Bratina]

Shawn-
I think it was Bratina that posted he's gonna try the 437's although I've been using them for at least 5 or 6 years since Dave recommended them and I like them.
I also use his suggestion of gapping at .038~040 for a bit hotter burn.

Again, IRMV...

Yup, it was me I got them in the mail last night. Thanks for the gap recommendation - I'll report back once they've gotten a few months on them after launch.

Had to look up IRMV..