checking spark F115TLRC

[dray0151]

Reading a thread recently there was a lot of talk about checking spark and not leaving wires open and if the engine starts turn it off?

If you have four gap testers one for each plug is it an issue to let the engine run while all four are connected and seeing that the spark is nice and blue?

[99yam40]

what type of spark tester are you using?
for all the plugs to be hooked up and the spark plugs still be able to spark and let the motor run ,it would have to be an inline tester.
The gap you have in the tester and the gap on the plugs will have to be added together for finding how big of a gap the spark can jump

bigger the gap the higher the voltage is need to jump it. spark will jump at the lowest/least amount of resistance.
If that happens to be inside a coil or across some terminal instead of the plug or tester and the voltage is high enough it will find someplace to go

[dray0151]

Its an inline tester plugged into the plug and of course a prong into the wire. The tester package states nothing about gap of the tester?

[99yam40]

is it a light that lights up or can you see spark jump a gap?

Apparently it is not an adjustable one.
I believe I have read that they should be able to jump a 7/16" gap, as long as all gaps added together do not exceed that it should be OK to let it run, but never thought about it before or tried that

[dray0151]

trying to upload photo but not working yet.

[boscoe99]

Some testers just test for spark. Using a fixed gap.

Some test for spark and how far of a gap the spark can jump. Using a variable gap.

Think about an old style distributor in an auto/truck. There was a gap that had to be jumped in the distributor before the gap in the spark plug was jumped.

Now I gots to thinkin. Is jumping two .020" gaps the same as jumping one .040" gap?

[dray0151]

Pic of tester

here is pic. may be hard to see, looks like glass with wire wrapped around it

[99yam40]

I would think so.
voltage just has to get high enough to jump what gap is set.
smaller the gap the less voltage is needed.
I am sure the ignition systems are capable of jumping way larger gaps than are set in plugs plus other gaps if there are any.
main thing is to not force the voltage to build up high enough to jump in places it should not

[dray0151]

I got to thinking and you can unscrew the cap it is a bulb inside the glass case inside a spring like wire. Not adjustable to my way of thinking.

[99yam40]

then you cannot see the spark, just see a light as it lights up

[dray0151]

Then you are saying you wont really see if it is a strong blue spark or a weaker spark is that correct?

[rodbolt17]

dude, buy the correct tester.
it is a 12V TCI waste spark system.
1&4 fire and 2&3 fire.
they fire in pairs.
need to test them in pairs.

[throrope]

I suggest buying new plugs and installing with antiseize. https://www.permatex.com/products/lu...e-lubricant-2/

IMHO, the greatest risk to aluminum heads from plugs is removal and installation. Soft aluminum is easily damaged by cross threaded plugs. I prefer to spend the few bucks for new plugs and forgo the potential damage from checking them. Also, the flexing and pulling on ignition wires may also lead to premature failure and since some wires are integral with coils, a simple spark plug check can get real expensive.

I recall replacing buried plugs on a truck resulted in a misfiring engine. Only after fussing into the evening did I notice the lightning storm over the engine. My struggle with the wires pushed them over the edge, opened a bunch of carbon tracks and all kinds of arcing. Never again.

[99yam40]

never use any thing that contains copper on aluminum threads

[fairdeal]

never use any thing that contains copper on aluminum threads

talking spark plugs, now - please explain