Spark Plug Torque...
10-27-2010, 11:48 AM
#31
6th Gear Member
Join Date: Oct 2006
Location: Texas
Posts: 10,551
I had a bit of time this afternoon, so I drill and tapped a slug of 7075 aluminum to 14x1.25mm, made a tapered seat and did a couple tests.
After running down a spark plug into the fixture at 60lbft a couple times, to form a good seat, I hand tightened it and torqued it to 15lbft (180lbin) using my 5-year old Harbor Freight 1/4" drive torque wrench--it turned a bit more than 22.5°.
I then used a Snap-On 1/2" drive dial indicator wrench to turn it to 90°. It took 47lbft to swing it 90°...
Here are some photos:
After running down a spark plug into the fixture at 60lbft a couple times, to form a good seat, I hand tightened it and torqued it to 15lbft (180lbin) using my 5-year old Harbor Freight 1/4" drive torque wrench--it turned a bit more than 22.5°.
I then used a Snap-On 1/2" drive dial indicator wrench to turn it to 90°. It took 47lbft to swing it 90°...
Here are some photos:
10-28-2010, 10:41 AM
#32
3rd Gear Member
Join Date: Mar 2010
Location: KS
Posts: 555
If I have a torque spec, I torque it to that torque spec; I dont care what its on.
Also, that is a crazy inconsistant way to do things. Who says that handtight is the same for everyone, or even repeatable for every plug hole? I just dont understand the whole, I dont need a torque wrench cause im a badass and iv been doing this for years attitude about stuff(im not talking about you really, just a passing comment). If you have the tools, why not use em.
Also, that is a crazy inconsistant way to do things. Who says that handtight is the same for everyone, or even repeatable for every plug hole? I just dont understand the whole, I dont need a torque wrench cause im a badass and iv been doing this for years attitude about stuff(im not talking about you really, just a passing comment). If you have the tools, why not use em.
I do however agree even spark plugs should be properly torqued.
10-28-2010, 06:42 PM
#34
to be honest i've never heard of torqueing spark plugs. i have never seen anyone do them, and i work in the field. pretty much the only things that i torque are things that have finicky gaskets, ex: heads, intakes, valve body's, aaaaand that's about it. i don't torque front covers, valve covers, oil pans, trans pans, tb's, plenums, etc.
10-28-2010, 07:30 PM
#36
4th Gear Member
Join Date: Jul 2008
Location: NC
Posts: 1,956
I have used a torque wrench both times I put in spark plugs. One time just to replace stock plugs and recently to put in NGK TR6s for the KB. I start by hand starting with a couple 1/4th inch extensions connected to eachother(this prevents chances of cross thread hugely). As soon as I get it hand started I opted for my cheap *** torque wrench that uses an arrow indicator that moves left and right(tighten or loosen). I find that my 120+FT/lb torque wrench(all metal with twist handle) is a lot harder to use accurately in the 10-25 ft/lb range. I found that when I loosened my stock motorcraft plugs they were at about 21-25 ft/lbs. I tightened them back to the same for obvious reasons and i've had no issues with combustion.
10-28-2010, 07:35 PM
#37
10-28-2010, 07:42 PM
#38
TECH SAVANT
Thread Starter
Join Date: Dec 2006
Location: Saint Augustine, FL
Posts: 10,938
to be honest i've never heard of torqueing spark plugs. i have never seen anyone do them, and i work in the field. pretty much the only things that i torque are things that have finicky gaskets, ex: heads, intakes, valve body's, aaaaand that's about it. i don't torque front covers, valve covers, oil pans, trans pans, tb's, plenums, etc.
You have obviously then never been anywhere near a NASCAR, NHRA, or any other pro race series pit--where everything gets properly torqued.
I admit I have often not torqued flat seat plugs with crush washers, on lawn mowers and such (where BTW hand tight +90° is the right load for new plugs, or if using new washers), however I have always torque tapered seat plugs--and only a fool would not torque the plugs on an engine known to have plug blow-out issues.
------------------------------------------------------
I guess never been in an aircraft hanger either...
10-28-2010, 07:57 PM
#39
6th Gear Member
Join Date: Oct 2006
Location: Texas
Posts: 10,551
I have mixed feelings here... Are you saying you torque every screw, nut, and bolt on your car when you are working on it? Technically every piece of hardware that attaches to your car has a torque spec somewhere.
I do however agree even spark plugs should be properly torqued.
I do however agree even spark plugs should be properly torqued.