H*ll yeah! Score 10 for a good answer! I want one of your gin and
tonics, lol....
But Harleys use aluminum heads and in truth do need an anti seize
because the instance of plug to head galling after prolonged use is
higher with aluminum and steel plugs than the plain old cast iron heads
and steel.
mayf
A Grey Goose kinda guy
______________________________
drmayf
Worlds Fastest Sunbeam, period.
204.913 mph flying mile
210.779 mph exit speed
On 4/18/2012 10:50 PM, genepadgett@comcast.net wrote:
> Curt, my gin and tonic is encouraging me to reply :>)
>
> I intended my post to focus on the real objective of determining "how tight"
> the plug should be. Torque is a proxy for that clamping force and for a given
> clamping force objective is a variable depending on the lubrication or not on
> the threads. As you seem to agree, lubricated threads, having lower friction
> between them, will turn further before stopping at a specific torque.
> However, the lubricated installation will have a greater tension in the plug
> body, being stretched more. Or so I submit.
>
> Perhaps you can rationalize your view with ARP specifying lower installation
> torque for their head bolts depending on whether the threads are lubricated
> or not and what is the lubricant..
>
> As for Harley specifying anti-sieze, I submit that they, like ARP, have
> determined what is the desired clamping force (i.e., stress within the plug
> and sealing objective) given the effect of the specified lubricant and
> written their spec accordingly. Not unlike ARP and their head bolts.
>
> To the extent that anti-sieze is in any way a lubricant is a separate
> question, but I subjectively submit it has some lubricating properties above
> zero. Whether it is materially different than dry is a totally different
> question.
>
> Cheers (!)
>
> Gene
>
>
>
> ----- Original Message -----
> From: "Curt Hoffman"<choffman9@cinci.rr.com>
> To: tigers@autox.team.net
> Sent: Wednesday, April 18, 2012 11:27:13 PM
> Subject: Re: [Tigers] Anti-Seize on Spark Plugs
>
> Very common automotive blog material as to whether torque is affected by
> anti-sieze. Shows up on every car list I am on. I have seen engineering
> papers written on it. I personally, also being an engineer, subscribe to the
> side that torque is a static measure while the lubricants tend to more
> affect friction in movement. There is very little movement at the end of the
> torqueing of a bolt and I find it hard to believe the antisieze would affect
> the value to any great degree. Since my Harley recommends antisieze on the
> plugs, and are very careful about torques for everything on the engine, I
> stick with the "no real affect on torque value" position.
>
> Curt
>
> -----Original Message-----
> From: tigers-bounces@autox.team.net [mailto:tigers-bounces@autox.team.net]
> On Behalf Of genepadgett@comcast.net
> Sent: Wednesday, April 18, 2012 6:14 PM
> To: rfraser@bluefrog.com
> Cc: Tiger's Den
> Subject: Re: [Tigers] Anti-Seize on Spark Plugs
>
> Just a caution to all about specific torque figures. The 15 - 20 ft- lb
> figure in the shop manual is probably a dry torque figure. Anti-sieze on the
> threads acts as a lubricant. It will result in a considerably tighter actual
> clamping force (and stress on the plug threads) at a 15-20 ft-lb torque
> reading than you would have at the same torque and no anti-sieze .
>
> Gene
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