Spark Plug Torque--Not By Hand!

[Jason2tpa]

I's something how some people can solve "Rubiks Cube" in moments and others can't ever?
On NGK "crushable gaskets" are three stamped flats in the ID (others have four). These must be lined up in the spark plug threads properly in order to unthread from the plug. Here's a video that shows the gasket being removed and contains ferrous metal (click on image).

[IMG]15375246_1736673533326855_2560081111514349568_n by Charles Postis, on Flickr[/IMG]

I normally don't worry about the gasket, but if you remove and re-install several times, why not change the 15 cent gasket? You guys change your gear case drain screw gasket every time, don't you?

Now, do you guys know the most important role in a "crushable gasket"?
Heat transfer!
Take a gander at this.

https://www.ngk.de/en/technology-in-...and-heat-flow/

40% of heat removal from the cylinder to the head is through the "crushable gasket". It increases the surface area of the transfer area. I know you guys always install your plugs and gaskets oil free, clean and dry, right? The hotter the plug range the more critical the heat transfer area is.

Very interesting read. I had thought the most important role of the crush gasket was as a seal. Now you have to wonder, if you're reusing a crush gasket then it no longer has the preformed corrugated surface area to transfer heat. So this heat that is normally transferred to the gasket is going somewhere else. Replacing the 15 cent gasket when reusing plugs doesn't sound like a bad idea.

[cpostis]

For a copper gasket what should the condition of the metal be in for it to seal properly?

Does anyone take the time to heat treat (anneal) their copper gaskets to ensure they seal and transfer heat as they are supposed to?

Stuff on the surface might appear to be simple but in reality it is not always so. There is a lot more going on in a spark plug than simply making a spark.

Interesting Boscoe! I just had top look this up.

https://www.youtube.com/watch?v=YSRx3k8domw

That Kevin guy seems to know his "Old School" stuff!

Early in my career as an apprentice, I had to anneal large diameter copper air conditioning pipe (over 3") to bend at an odd angle. This was in a new temple with a $2 million dollar hardwood ceiling that had the have the pipe concealed in minimal space allowed. The old time journeyman should me how to do it. We had two men on the pipe with rosebud torches heating them up red hot then bending the pipe while it was red. Some bends kinked. I got reamed out by the journeyman. He got peed, off left me alone with another apprentice and we heated the pipe, quenched it and used a bottle jack and a rigged a "wood die" to the angle we needed. Not a kink in the remainder of the custom bends.

The journeyman bought us lunch and then a few beers after the day.

[boscoe99]

For a copper gasket what should the condition of the metal be in for it to seal properly?

Does anyone take the time to heat treat (anneal) their copper gaskets to ensure they seal and transfer heat as they are supposed to?

Stuff on the surface might appear to be simple but in reality it is not always so. There is a lot more going on in a spark plug than simply making a spark.

[99yam40]

Seems like I remember oil seepage around plugs before on 2 strokes.
I do not believe you would need to worry about leaking compression thou

[cpostis]

actually, the little NGK "cartoons" ARE referring to the standard gaskets

the copper washer and taper seat are separately addressed there.



I can believe its aluminum

certainly a complicated shape

I've always marveled that they get it on there, but it doesn't want to come off....

I's something how some people can solve "Rubiks Cube" in moments and others can't ever?
On NGK "crushable gaskets" are three stamped flats in the ID (others have four). These must be lined up in the spark plug threads properly in order to unthread from the plug. Here's a video that shows the gasket being removed and contains ferrous metal (click on image).

[IMG]15375246_1736673533326855_2560081111514349568_n by Charles Postis, on Flickr[/IMG]

I normally don't worry about the gasket, but if you remove and re-install several times, why not change the 15 cent gasket? You guys change your gear case drain screw gasket every time, don't you?

Now, do you guys know the most important role in a "crushable gasket"?
Heat transfer!
Take a gander at this.

https://www.ngk.de/en/technology-in-...and-heat-flow/

40% of heat removal from the cylinder to the head is through the "crushable gasket". It increases the surface area of the transfer area. I know you guys always install your plugs and gaskets oil free, clean and dry, right? The hotter the plug range the more critical the heat transfer area is.

[robert graham]

The question is whether or not anyone has ever had issues because of re-use?
I never have....

My motor is a 1999 and has the original plugs and washers....I sandblast any carbon off plugs a couple of times a year....plugs look and operate just like new ones and no issues with the washers either.....also, "good and snug" seems to work well.....spark plugs ain't brain surgery to me....hand tighten then snug with a wrench....

[TownsendsFJR1300]

I just put a magnet to an old Champion lawn mower spark plug with gasket (looks the same as pictured).

My magnet DOES GRAB gasket pulling it up. (against gravity)

[fairdeal]

actually, the little NGK "cartoons" ARE referring to the standard gaskets

the copper washer and taper seat are separately addressed there.



I can believe its aluminum

certainly a complicated shape

I've always marveled that they get it on there, but it doesn't want to come off....

[TownsendsFJR1300]

Too bad the gaskets in the diagram are copper, not the aluminum "crush" gaskets used on most plugs for Yamaha outboards.
The aluminum gaskets are avaiable from Champion @ 15 cents a piece.
https://www.sparkplugs.com/N678-Cham...p26421.aspx://

That link doesn't work...

I don't believe the gaskets are aluminum(I may be wrong), but steel (appears the same finish as the plugs themselves).

With that said, I've replaced (98% small engines) with crush-able gaskets MANY times without an issue (by hand yet). I talking 3,600 RPM large 4 strokes (single cylinder, up to 10HP) to 8,000 RPM single 2 strokes.

Never had one leak, nor thought ANY about it...

[cpostis]

You are always making way too much sense.

Too bad the gaskets in the diagram are copper, not the aluminum "crush" gaskets used on most plugs for Yamaha outboards.
The aluminum gaskets are avaiable from Champion @ 15 cents a piece.
https://www.sparkplugs.com/N678-Cham...p26421.aspx://

[boscoe99]

here's what HGK themselves have to say about installing "Reused" spark plugs:

if you are not using a torque wrench, the "tightening angle" is reduced

(presumably, because the gasket has already been "crushed")


The illustration shows a substantial reduction for the standard gasket.

Less of a reduction for the solid copper type gasket.

And naturally, no change for the gasket-less taper seat style plug.

You are always making way too much sense.

[fairdeal]

We know the purpose of the crush ring is to provide a seal between head and plug. The even bigger question is, IS the seal compromised when mounting the plug for 2nd time and thereafter? And if so, is the amount of compression lost significant enough to worry about?

here's what NGK themselves have to say about installing "Reused" spark plugs:

if you are not using a torque wrench, the "tightening angle" is reduced

(presumably, because the gasket has already been "crushed")


The illustration shows a substantial reduction for the standard gasket.

Less of a reduction for the solid copper type gasket.

And naturally, no change for the gasket-less taper seat style plug.

[Jason2tpa]

We know the purpose of the crush ring is to provide a seal between head and plug. The even bigger question is, IS the seal compromised when mounting the plug for 2nd time and thereafter? And if so, is the amount of compression lost significant enough to worry about?

[pstephens46]

the big question is where do you find replacements without buying new plugs?

The question is whether or not anyone has ever had issues because of re-use?
I never have....

[99yam40]

the big question is where do you find replacements without buying new plugs?