Spark plug torque?
Thread Starter
Burning Brakes
Joined: Dec 2003
Posts: 1,183
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From: MidOhio
Spark plug torque?
My '89 GM 'vette service manual calls for 22 ft-lb torque on the spark plugs in the aluminum heads. So does my '89 GM Caprice manual for 305 cu.in. iron heads. I would have thought the alum torque would have been lower. Any wisdom on this out there??
Thread Starter
Burning Brakes
Joined: Dec 2003
Posts: 1,183
Likes: 1
From: MidOhio
Originally Posted by C4driver99
Follow the GM service manual. It comes from the engineers who built it.
Thread Starter
Burning Brakes
Joined: Dec 2003
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From: MidOhio
Originally Posted by Corvette Kid NC
With anti-sieze on the threads, 15 lbs. will be enough.
Instructor
Joined: Jun 2004
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From: 1987- L98, auto OH
Hmmm... My Haynes manual (got it early on before I got the factory manual) says 22 ft/lbs for iron heads and 12 fl/lbs for aluminum heads. I set mine to 12 lbs with anti-seize for my aluminum headed 1987 and they haven't seemed to have any problems, but now I'm worried. I may pull and check a couple. My factory manual (bought it after the tuneup) says 22 lbs...seems a bit high for an aluminum head!
Brad
Brad
Racer
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From: Tucson, AZ. L98-85 AUTO COUPE: 120k MILES: daily driver. SOUND OFF IF YOU'VE BEEN THERE. Ex-Jumpin' Junky-82nd Airborne-2/505 PIR: 1st ID-1/16th Inf: Recon Marine Retread. GOD BLESS GRUNTS.
Originally Posted by Corvette Kid NC
With anti-sieze on the threads, 15 lbs. will be enough.
i would think that a general consensus of torques would be a good bet since everyone is basiclly talking about the max abilities of aluminum threads to hold steel without stripping. it's essientially more a concept and less a detail.
i understand what you mean about misprints in your year service manual. i just found a major misprint in the 85 manual that might make the rear wheels fall off. just cause a manual is approved, that doesn't mean it doesn't have mistakes in it. thems full of a lot of words.
"there is no such thing as a dumb question--just dumb answers"--Poppa Frog.
"god bless the enlightened and the tolerant"--Bubba Rumraisin.
frog.
Last edited by parafrog; Feb 15, 2006 at 07:17 AM.
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Drifting
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From: Sacramento, CA Money can't buy happiness - but it's more comfortable to cry in a Corvette than a Yugo.
I was concerned about overtorquing the plugs also. I know that the Factory Shop Manual is not written by GM Engineers, but by Tech Writers who sometimes misinterpret or make mistakes writing down what the Engineers say. Since my Kawasaki uses the same size and thread pitch spark plug as my 88 Vette, and both the bike and the Vette have aluminum heads, I looked at the my FSM from big K. Both shop manuals specify 18~22 ft.lb. torque. I use anti-seize and torque both to 19 ft.lb.
Burning Brakes
Joined: Feb 2000
Posts: 824
Likes: 2
From: Camden SC
With aluminum fittings, low range torque is perfectly acceptable to me.
As a note, those advertising 100,000 mile spark plugs in aluminum engines may have a 50,000 mile inspection requirement. Keeping a spark plug in an aluminum head for 100K may not be a good idea.
I don't hate aluminum, just seems to do its own thing.
dlmeyers 90 coupe zf6 3pseed shocks
As a note, those advertising 100,000 mile spark plugs in aluminum engines may have a 50,000 mile inspection requirement. Keeping a spark plug in an aluminum head for 100K may not be a good idea.
I don't hate aluminum, just seems to do its own thing.
dlmeyers 90 coupe zf6 3pseed shocks
