reading plugs

[spib]

anyone have any good links on the subject of reading plugs, and also need to buy a light for reading plugs anyone have a good magnifing light for looking at plugs, summit , jegs etc, what do you guys use?

[mytmouz]

Pretty good info somewhere in the tech section on the dragstuff board Mark...

[406shark]

I've used this site will success in the past.
http://members.uia.net/pkelley2/sparkplugreading.html


Jeff

[jameskirk1]

They make AFR gauges for that now - keeps dummies like me out of trouble :D

[83blazerV8]

there out there but to have a good plug reading it has to be shut down at the end of the run most people think they can read a plug after drive back to the pits it wont happen it gets contaminated

[1fast10]

Wide bands work but still don't lie like a plug.when I worked at a performance shop we had a chassis dyno and we read both.only issue with wideband o2 is it reads the average of that bank of cylinders.you can have 2 real lean holes and 2 rich holes and the wideband will see a decent reading when in reality its off.I personally think a wideband should be used as a data log tool not the only think you look at.exspecially in a drag motor were a hole can.go any time.reading plugs will alwasy tell you what a.motor wants.for intance most sbf motors run lean on the outside cylinders.if we tuned off the o2 we would possibly burn these holes up.the plugs will tell us how to adj these holes.


Now reading plugs is a huge debate in its self.I like to have the fuel ring at the base of the porcelin. And the electrodes likes the timing at the bend on my motor.I have see..them like different things so that may change.I have seen rich motors like no timing and the same motor leaned out un a lot more timing.this was based on mph at the track .but normally I get the fuel ring below the porcelin then start adding tonigh back so it until mph falls off.the. I go back to fuel and take fuel out until it gains no more mph or add fuel for most mph .usally when I do this I end up with a text book plug.timing mark in.middle of bend and fuel ring at base of porcelin but not climbing up the porcelin

[ron406]

nice thread Jeff thanks.

[spib]

man this is a old thread that got picked back up on dyno my motor started to denoate at 36 degrees so I run my timming at 34 and run 86 square jet and run the shit out of it

[83blazerV8]

and this is read at shut down 1fast10 just to clarify!!! not after driving back to the pits

[1fast10]

Yes you are correct on shut down.most guys will even make a half pass and kill it.if your engine is pretty lean then you can sometimes get away with driving back but it will show some signs.when I'm tuning a nitrous engine I always run the plugs 2-3 runs and change them after that you can't see any changes.if its a big system we change plugs every pass