Proper Way to Gap Spark Plugs?

Everytime I change my spark plugs, I have a hard time gapping them. I use the round disc-type gapper (size of a half dollar coin) so I can adjust the gap to the exact size I need, the kind you can get a most auto parts store for $0.99 or so.

By hooking the grounding prong (is that what it's called?) of the spark plug over the hole in the spark plug gapper, I can get the prong to move away from the other prong (similar to opening a bottle cap), as the gapper gives me the leverage to do this. But it always bends too far away. And getting the prong to move back in is a pain. I usually end up trying to press the prong against a hard flat surfaced to bend it in. It takes me about an hour or more to gap just four plugs!

Is there an easier way? Thanks,

Julie

Reply to
Julie P.
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Reply to
Shep

Thanks, but the parts store guy said the round type is better, since you can gap to any gap, while with the wire gapper, you are limited to only a few pre-set gaps.

And how would a wire gapper work any better than a disc gapper?

Julie

Reply to
Julie P.

I think your fundamental problem isn't the gapper, it's how to bend the plug to get the gap you want without a lot of over/under shooting. IMO, the only way to get better at that is experience. Just try to open/close it in small increments until you hit the gap you need without a lot of back and forth.

John.

Reply to
John 'Shaggy' Kolesar

Reply to
Shep

Thanks John, and also Shep. I will see what I can do. I am doing my spark plugs and valve cover gasket tomorrow.

Julie

Reply to
Julie P.

Have you tried to close the gap on the plug with it on the gapper?? Just tap on the plug or the ground prong while it is in place on the coin like gapper....

Good luck..

Fwed

Reply to
fweddybear

Thanks Fwed, I thought of this, but am worried I would damage the plug if I used a metal hammer. And a plastic or rubber hammer would not be hard enough to adjust the prong with--that thing is pretty stiff and hard for me to bend.

Julie

Reply to
Julie P.

Struth, an hour? It should take about a minute per plug. I don't normally use any special tools, just a watchmakers screwdriver to open the gap if necessary (only on copper electrode plugs NOT the thin platinum ones) and feeler gauges to set and measure it. To close the gap just insert the required thickness of feeler gauges, hold the plug upside down and tap the earth electrode gently on a heavy, solid piece of clean metal (steel plate, old cylinder head, the top of a vice etc) until the feeler gauge is a nice sliding fit.

To open the gap if it starts off too small.

1) With copper electrodes you can insert a watchmakers screwdriver and gently lever the electrodes apart a bit making sure not to apply any side force and break the insulator.

2) With platinum electrodes you'll need the hook tool because the platinum electrode is too thin to lever against.

Always set your gap by starting off too big and tapping the earth electrode back down to size. If you bugger about with the hook tool trying to bend the earth electrode to an exact gap you'll be there for ever - which clearly is where you're at right now. You're always fighting the spring in the material when you try to bend metal to an exact size. However, by tapping gently you can achieve a very precise control over how much the gap alters per tap. Similarly, never try to just press the gap down to size by pushing the plug against a vice. That's just applying a bending force but by another method. It requires a sharp, but light, impact to obtain control over the material deformation.

-- Dave Baker

Reply to
Dave Baker

I use a wire gapper. It takes around 20 to 30 seconds per plug. If I over gap it, I tap the plug on the concrete floor or some heavy metal part. I never use the bender thing to close the gap. My favorite wire gapper is the kind that folds out like a pocket knife.

Reply to
« Paul »

Yep, or more! It was so hard for me to press the grounding prong of the plug against the gapper in order to close the gap. It's hard to bend in that way. And I never put the gapper on hard surface, since I didn't want to scratch it up (like my tools nice and shiny :) ).

It should take about a minute per plug. I don't normally

You mean tap on the connector part, where the wire connects? I would be worried I would accidentally crack the ceramic insulation part then. And if I tapped on the other end, wouldn't the plug be wobbly as I tapped it?

Thanks Dave! I will see if I can find that watchmakers screwdriver. I need to change a watch battery anyway, and I think I saw them for cheap at HarborFreight.

Julie

Reply to
Julie P.

Thanks Paul!

Julie

Reply to
Julie P.

I'm surprised to see all this discussion about plug gapping. I use ND platinum plugs and a wire gauge. Don't like to even touch the electrodes so I use a "go" or "no go" method, and they seem to be right on from the factory. Seems like many years ago I needed to adjust plug gaps with conventional plugs about the time I was setting ignition point gaps and dwell. Plus with modern electronic ignitions, there's plenty of voltage - makes me wonder if being a thousandth off is too critical - and I'm generally extraordinarily precise in all automotive work. The general consensus here is correct though, just widen the gap and then gently tap the ground ("hook") electrode just enough to move it in sufficiently. IIRC I used to tap it on the concrete garage floor.

Reply to
nospampls2002

I like this method of riding the plug up the taper. I had thought of this before, but was always worried I would ruin either the gapper or the plug this way. But it really doesn't matter, as plugs are cheap, as is the tool. :)

Julie

Reply to
Julie P.

I've read it's important to keep the positive electrode flat so it should be bent at the base, not at the spark end. To do that I use the notch provided in the guage slipped around the base of the electrode. For control I steady the spark plug and the guage by holding them tight against my chest. I've never hit the electrode to bend it and have no problems getting the correct gap. Maybe I'm just a more sensitive guy. :)

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Reply to
William R. Watt

Indeed, the wire gapper is the proper thing to use for plug gaps, especially used ones. The problem is you are measuring the space between two curved surfaces. The use of a feeler gauge, especially on used plugs, is that you will get an increased gap as the flat gauge fits between the two curved, reasonably concentric surfaces.

Reply to
Don Stauffer

Yeah, don't make a mountain out of a molehill. If you over-gap or under-gap by +/- five thousandths (.005), forget it. Its not THAT critical.

Wire or feeler-guage gappers are more accurate than the round ones, but they have the same issue of bending the electrode. When I use a round disk gapper, I usually just "rock" the tool to spread the electrodes as I slide the plug along the measuring surface. Can't do that with Bosch platinum plugs because the ceramic will crack, but that's what anyone deserves for using crappy Bosch platinums anyway :-p

Reply to
Steve

Do you really need to set the gap, except when reusing old plugs? Because every plug I've checked was gapped exactly right from the factory,

For the smaller gaps I've used a wire gapper that was included with a set of feeler guages, and for wider gaps I use the feeler guages. It has a gapping tool, but to close the gap a light tap with a hammer works too.

Reply to
larry moe 'n curly

1 hour! I can't see it being good for the electrode to be bent back and forth that many times. It might break off. Many spark plugs can be purchased with the gap already set. Just double check it and save yourself 55 minutes. The other advice I would give is that the tool you use to open the gap needs to be longer. That way you can have more control over how much you open the gap. You also need to keep in mind that you don't need to be exact, which you can't be with the disk gapper you use anyway. Close enough, is close enough.

------------- Alex

Reply to
Alex Rodriguez

I was thinking to have the p;lug already on the coin like gapper and just tap the prong on something sturdy until the gap closes to the right size.... i do it all the time and never have I broken the prong off...no need for a hammer tap it while in your hand....

Fwed

Reply to
fweddybear

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