OEM spark plug threads
10-19-2015, 07:07 PM
#21
before reading some of Bill's posts I tended to use around 18 ft lbs torque on the my plugs, and I always found them really tight when it came to removal. I've since gone over 20 ft lbs for extra insurance, I just never find my plugs loose.
10-20-2015, 03:11 AM
#23
I have a note penned in my shop manual that says the torque should be 24 lb-ft. This is up from the original 18 lb-ft. I think that came from one of Bill's earlier posts and/or Honda.
New OEM-spec NGK (7746) IFR7G-11KS plugs have anti-seize on the threads (plating?).
-- Chuck
New OEM-spec NGK (7746) IFR7G-11KS plugs have anti-seize on the threads (plating?).
-- Chuck
10-20-2015, 03:52 AM
#25
^ I never install or remove plugs on a hot motor.
10-20-2015, 04:59 AM
#26
10-20-2015, 05:03 AM
#27
10-20-2015, 07:50 AM
#28
Registered User
Originally Posted by cosmomiller' timestamp='1445273898' post='23779921
spark plug failed before the head threads stripped
Was able to click off 75 ft-lbs.
When I stepped up to 80, the threads broke off the spark plug in the head.
Was able to spin the broken threaded piece out with pliers from the cylinder side.
Afterwards, I put a new plug in the hole. It went in with slight resistance as the threads were barely deformed.
Was able to torque to spec no problem. It could likely take another 70 ft-lbs.
Good insurance that 24-26 ft-lbs is super safe.
A lose plug will allow combustion gas to torch the threads resulting in stripping. Very safe to say if the threads are stripped, it was followed by torching.
10-20-2015, 11:59 AM
#29
I actually read that it is okay to remove plugs as soon as you turn off the engine, don't do it say 5 minutes after shutdown, either completely hot or completely cold. To reinstall plugs wait for the motor to cool down.
You know that a mechanic shop isn't going to do that though, they just want to the compression check done asap, so they will do it however they want.