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Check the owner's manual for your vehicle or contact a certified BMW repair center and find out the correct gap. You can then buy a "gapper" at any parts store for about $3. It will be a simple wedge device with measurements on it. you slide the wedge into the spark gap until you reach the appropriate gap. It's pretty simple assuming you can get to all of the plugs.

When you get it adjusted, go for a nice long drive to see how smooth it runs. -WanderingWineGuy

You need a sparkplug gapping tool, cost is 1.19 at most parts stores, ask the employee to look up the required gap for your vehicle, and ask them to demonstrate the proper use of the gapping tool.

Newer cars use a platinum, or iridium tipped plug, and by using the gapping tool as most of you have indicated, will damage the plug. Most gapping tools have a beveled edge, which is only for checking the gap, not adjusting. On the opposing side, there will be a hole (not for a keychain), to which you slide over the prong, and adjust it by stretching it away from the electrode, or by pressing it towards the electrode. Do this until your gap is within +/- .003" of the required gap.

you should be able to go to any auto store web site and find out your gap size..once you know the gap distance the sell a little tool for about 1.00 at the auto part store just stick the round tool in between the spark plug gap and turn until you reach the right gap...the gap in a spark plug makes sure you get the appropriate spark to burn all the fuel in the cylinders..

A.C. Delco #'s are more appropiate for what you ask. Most H.E.I. equipped Chevy small block V-8's call for .45 to .60 gaps. The .60 gap was for 350's built for the new "unleaded gas of '74-76' model years of all chevy design. Many other gm v-8 engines whent as far as .80 gaps with Hei distributors. I've experimented with this and found that a .55 gap is a good starting place if you are willing to change the heat ranges up and down through the seasons. A.c. plugs are the most reliable to tune through these variable seasons. I'm subject to alcohol fuel and allways measure the water level before making a change.

post plugs come pre gapped but for 1 dollar you can buy a spark plug gapping tool at any auto parts store and they can tell you proper gap

The gap distance is marked under the hood on a tag either on radiator cover or under the hood.

You gap them with a gap tool, available at any parts store.

the gap is the distance measured between the tip,and the outer electrode on them if you,ll look in the owners manual it will tell you what the gap should be ,or its also on the specification sticker ,when you raise the hood you,ll see it,if not call any parts store they will be glad to tell you what the gap is,re-setting the gap will make it run a lot better,good luck on it.

You buy a gap tool. They look like: http://www.royalenfieldusa.com/images/SPARK%20PLUG...

You put the tool in the spark plug gap and slide the tool until you have the correct gap.

a $1.00-$2.00 gap tool that you can get from the part store and they can give you the spec when you buy the plugs if you cant find it under the hood on the engine sticker

depends on the year make and model