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[epsylon]

How important are those little washers that sit in between the spark plug and the head? I just changed all four plugs and left one off one of the plugs, not sure which one. Should I pull all off the plugs and redo or will everything be OK. Car runs fine for now and I am wicked lazy.

[JvGinPDX]

As I recall, they are there to be crushed the first time you install the plugs, this would geive a good compression seal. If a plug is reinstalled, the seal will not be as good. If there is no sealing ring, there would be a compression leak. How much of one is any ones guess.

[gohim]

Sorry, you're going to have to go back and install the washer that you forgot.

[epsylon]

that's what i was afraid and why i asked. thanks for the help. maybe i should try being more percise and doing quality work instead of rushing.

[larso]

They help seal a lot. Replace the washer when you can. AC delco has some little message on their spark plug cardboard that you buy the spark plug in, it says something like "AC delco makes spark plugs that seat properly, seating is much more important than the actual plug type (platinum, copper etc.). I don't know if they are just trying to sell spark plugs, but it sounds reasonable. Also on the subject of washers, different sized washers (thickness), can maybe help your engine run better, or smoother. Combination of the position of the spark plug in relation to the combustion chamber, and the angle at which the spark plug's "arm" is facing. It's a tuning trick, but on a 924 the power difference will be so subtle that it won't even show up on a dyno probably. Not sure though.

[epsylon]

going to plug all of the plugs and replace all of the washers including the one i missed. what torque should i be using to crush those washers and not over tighten the plugs? i am not sure if i put enough torque to crush the washers, i just did it by feel, last ime.