Spark plug gap

[sandythelandy]

Hi all,

I'm about to change my spark plugs that I bought from RN for my 7:1 compression 2.25 engine. Since I bought these for the right engine, do I need to set the gap?

Thanks

[TeriAnn]

Hi all,

I'm about to change my spark plugs that I bought from RN for my 7:1 compression 2.25 engine. Since I bought these for the right engine, do I need to set the gap?

ALWAYS check the gap prior to installing new or used spark plugs. The gap might not be correct for your engine or may have been changed by a something impacting the end of the plug. They are almost always correct, but sometimes one will not be.

[sandythelandy]

Great, thanks. I've only changed plugs once and it was on an 07 subaru and had not idea that I should have checked them but it ran fine after that. I will get a gapper tomorrow.

Thanks again

[siii8873]

can I ask what plug you were sent?

[sandythelandy]

They sent me Bosch Super Plus 7904 which has a gap of 0.7 mm. I regapped them to .03" or 0.76mm because the green bible says they should be between .75 and .8 mm. I already changed them and the engine is running a lot better. I noticed that the gap on the old ones were nearly 1.5 times what they are supposed to be.

Hope that helps. I assume these were the right ones?

[siii8873]

are they the W7DC plugs? Should be another number on box something like this.

[bmohan55]

On a related note....I was told that when running Pertronix to set the gap at the upper limit for a hotter spark...is that correct?

[jac04]

On a related note....I was told that when running Pertronix to set the gap at the upper limit for a hotter spark...is that correct?
The Pertronix Ignitor is just an electronic switch taking the place of your existing points. It doesn't provide a "hotter" spark at all. If you installed one of the Pertronix Flamethrower coils, then you might get a little more spark energy. I installed the Ignitor, Flamethrower & Magnecor wires and I run the gap toward the high side of the gap as listed in the green bible. Some people experiment running a larger than factory spec gap, but I'm not sure if it makes a bit of difference.

[sandythelandy]

The box also says WR 8 CC+

[disco2hse]

The Pertronix Ignitor is just an electronic switch taking the place of your existing points. It doesn't provide a "hotter" spark at all. If you installed one of the Pertronix Flamethrower coils, then you might get a little more spark energy. I installed the Ignitor, Flamethrower & Magnecor wires and I run the gap toward the high side of the gap as listed in the green bible. Some people experiment running a larger than factory spec gap, but I'm not sure if it makes a bit of difference.

Just to add a little more, you can also use hotter plugs if that is what you want. Generally an engine in good condition will use the standard plugs but if it is starting to get a bit loose and tired then you may find hotter plugs will last longer and provide a better firing over a wider throttle range.

[jac04]

I installed the Ignitor, Flamethrower & Magnecor wires and I run the gap toward the high side of the gap as listed in the green bible. Some people experiment running a larger than factory spec gap, but I'm not sure if it makes a bit of difference.

Just a follow-up to this. I kind of lied I guess. I pulled my plugs today just to make sure everything looked good mixture wise. My plugs looked great. I checked the plug gaps and found that I was running about .038 instead of the .032 max. as listed in the manual. Like I said, the plugs look great, but .038 seems a bit large for the gap. I re-set them all to .036" and re-installed. As stated above, I'm not sure any of this will amount to a bit of difference power wise.