Loose spark plugs?

[anmut]

Wondering if anyone else has experienced this. When I change my plugs in the spring for the season, I hand tighten them in, then give them another half to three-quarter turn in to tighten them up. By fall, they're loose enough that it only takes about an 1/8 turn or so to bring them out by hand.

No performance issues found at all. I just wonder if these motors are seriously turning the plugs back that much - or if it's just warm motor (new plugs installed after warming up for oil change) vs. cold motor. Next year I'm going to index and count the turns on a few plugs for documentation later in the season.

 

[Adrian @ JB Solutions]

Get a torque wrench from Harbor Frieght and do it to spec.

 

[buckbuck]

@anmut I can say that is typical for me. One year I was able to back one out without putting the ratchet handle on it. Like you, I never noticed a performance issue.

 

[FSH 210 Sport]

Get a torque wrench from Harbor Frieght and do it to spec.

I think my manual states 12 ft lbs EDIT 9.6 Ft lbs… that is the way I tighten mine and they are still snug when I back them out, but not tight.

When the plugs are put in per the box of like 3/4 of a turn after the crush gasket hits it is typical for them to feel loose when you take them out.

 

[Adrian @ JB Solutions]

I think my manual states 12 ft lbs… that is the way I tighten mine and they are still snug when I back them out, but not tight.

When the plugs are put in per the box of like 3/4 of a turn after the crush gasket hits it is typical for them to feel loose when you take them out.

Should be 18.5 IIRC

 

[anmut]

I appreciate that - yeah, I have a tq wrench too, just never thought about using it on my boat plugs as I don't have any other plugs that walk out like that. Also, I'd rather have them walk out than get stuck and break... that gives me nightmares!

 

[FSH 210 Sport]

Should be 18.5 IIRC

Checked my service manual it’s 9.6 ft lbs for the TR-1’s

 

[Adrian @ JB Solutions]

Checked my service manual it’s 9.6 ft lbs for the TR-1’s

Good call! I have been working on the 1.8s. With the AR210 now, I probably would have overlooked that.

 

[drewkaree]

Have you ever used any anti-sieze on them?

 

[Babin Farms]

I'd rather have them walk out than get stuck and break... that gives me nightmares!

My thought as well.

 

[TeenGee]

The plugs have a crush washer. When you tighten the additional 1/2 - 3/4 turn you are crushing the washer. when you remove the plug the washer has been crushed and does not return to it's original thickness, hence the 1/4 turn to break free before hand tight.
You can verify this by measuring the thickness of the crush washer before installation and after removal.

 

[anmut]

Have you ever used any anti-sieze on them?

No - I know guys do, but that doesn't seem to be an issue when they walk themselves out...

 

[TeenGee]

The plugs are not unscrewing themselves.
To prove it to yourself, put a sharpie mark on the forward side of each plug. Verify it hasn't rotated prior to replacement.