Do you faithfully check sparkplug gap?

[4pwr]

I have to admit if I buy a pug that is recomended I do not always check and adjust the gap. Is a few thou off that important?

 

[Simonizer]

I have to admit if I buy a pug that is recomended I do not always check and adjust the gap. Is a few thou off that important?

No. A few thou is of zero consequence. If you stay +/- 0.005" there will be no difference what-so-ever.

 

[ray benson]

I have 2 saws that use a BPMR7A plug. One is gapped at 0.020" and the other 0.025". I check.

 

[Lewis Brander]

Plug gap:

I have to admit if I buy a pug that is recomended I do not always check and adjust the gap. Is a few thou off that important?

To me a properly gapped plug is more efficient than one that's not. On these new saws with electonic ignition systems heat is a big killer for coils and moduels. A plug that's gapped to wide may fire, but places more load on the coil/moduel to fire the plug, hence shorter coil/moduel life in the long run. JMO. Lewis Brander.

 

[Patrick62]

Plugs are gapped with a pocket knife. But only when necessary. I have had little trouble with the plugs. Maybe I should check them once in awhile....

about anything from .020 to .030 will work. Some stuff might be a little more picky.

-P

 

[Max]

I check them. Murphys law can strike at any time. If I checked it I know its correct.

 

[NevadaWalrus]

If a proper plug gap tool is kept handy with your other regularly used tools it only takes a few seconds to check and if needed adjust. I believe in checking but if you don't, whats a few seconds to be certain.

 

[smcowboy1974]

I gap mine 99% of the time. Only when I'm in a big hurry is when I don't. What Lewis Brander said I think makes sense. A plug is cheap compared to an ignition module.

 

[bvaught]

To me a properly gapped plug is more efficient than one that's not. On these new saws with electonic ignition systems heat is a big killer for coils and moduels. A plug that's gapped to wide may fire, but places more load on the coil/moduel to fire the plug, hence shorter coil/moduel life in the long run. JMO. Lewis Brander.

Yep, if you run too big of a gap you will overload your coil or magneto. Im not saying that being a little off will bring about the end of days, but it certainly pays to check your plug when installing a new one or when doing yearly maintenance to the saw.

 

[2Coilinveins]

I'll go with everyone else, I gap plugs when I'm not in a screaming hurry. I also use a wire-type gap tool or feeler gauges if they're more handy. I hate that twisted ramp looking thing.

 

[clearance]

Never thought about it, usually just put in a new Bosch plug, never had a problem but now I will check, thanks.

 

[Lawn Masters]

I usually buy plugs in fairly good quantities, and just gap em all at one time, then I dont have to worry about it later on if they're right or not. trust me, I've got about 20 plugs for 3 saws, and I keep finding them ALL over the place. time to reorganise my shop again.

 

[bvaught]

I'll go with everyone else, I gap plugs when I'm not in a screaming hurry. I also use a wire-type gap tool or feeler gauges if they're more handy. I hate that twisted ramp looking thing.

Agreed, the twisted ramp .99 cent gap tool is just a little bit better than worthless.

 

[klickitatsacket]

I gap all my plugs. Some thing I learned from an old bike racer; you can make slight timing adjustments to your engine by closing or opening your plug gap. I have closed the gap to as close as .010.

 

[PWB]

I gap all my plugs. Some thing I learned from an old bike racer; you can make slight timing adjustments to your engine by closing or opening your plug gap. I have closed the gap to as close as .010.

Good point, never thought of that trick. I'm assuming a smaller gap would mean an earlier fire?

 

[klickitatsacket]

yes a smaller gap is traveled faster. This will not create eye poppong results but it will help if you are trying to fine tune your engine.

 

[jokers]

I gap all my plugs. Some thing I learned from an old bike racer; you can make slight timing adjustments to your engine by closing or opening your plug gap. I have closed the gap to as close as .010.

Given that the free flowing electrons jumping the spark gap are moving at about the speed of light, 186,300 miles per second, I find it completely inconceivable that any variation in spark gap distance achieved with a standard spark plug is going to make any measurable or observable difference in the amount of time that it takes a spark to cover that distance.

Anyone care to try to explain to me how this could true?

Russ

 

[eric_271]

Russ I dont know that it is a timeing thing or not but when I used to drag race some times I played with the plug gap. If I went tighter then called for I lost rpms. The more I opened the gap back up the more my rpms came up. At a certain point to wide and things went to bad. I ''think'' a saw will do the same thing. Try if you want and set the points at less then called for and tach the saw, then open the gap a little more and tach again. The last time go a little past whats called for and tach again. You should see a differance in the top end rpms. Again Im not claiming that you are changing the timeing though that could be what you are doing. Im not even sure a 2 stroke will react the same but you can kill the performance of a 4 stroke engine by too far one way or the other on the plug gap.

 

[jokers]

Hi Eric,

I understand that you can alter the timing of the combustion event with the plug gap, what I don`t seem to grasp is how closing the plug gap is making the spark cover the distance of the gap appreciably faster or slower, or in any meaningful way.

What I believe is happening is that the flame propagation rate is being changed proportionate to the spark energy.

If we have any SAE engineers reading who would like to explain the error of my thinking, I`d like to hear the logic. Otherwise I guess that we are relegated to debating this as layman. I am curious to hear theories and opinions.

Thanks Eric for relating your experience and observations.

Russ

 

[jokers]

I see now that I quoted the wrong statement. I meant to quote this one;

yes a smaller gap is traveled faster.

Sorry for the confusion.

Russ