Jon Kerr

iTrader: (17)

I'm running an OS EB Mods V-Spec .21 in my 8IGHT. I've got about 3/4 gallon through it. So far every race day, I've gone through a P3 (the plugs EB says to run in the engine) plug. And they're not burning up. The elements are breaking. Twice I've had them break in the middle of a main where the car will stall, then when it won't start again, we pull the plug out and the element is broken. Every other time, it's after the main, I go to put after run oil in and check the plug and it's broken. The engine runs great, but what's the deal? I'm still not really clear on the different plugs. Is a higher number hotter or colder? Would you run a colder plug in hot humid weather? etc... It's been really hot and humid around here lately (100º+ and very humid) so I don't know if the P3 is too hot of a plug for that kind of weather or what. I was running O'Donnell 30% and I've started running Nitrotane 30% and it's done it with both fuels. I've got a bunch of Orion Turbo 6 plugs that I could use. I ran one in a qualifier and not having time to tune the needles, it ran like crap. Would that be a better plug? Is it a hotter or colder plug.

Sorry for the rookie questions. Still trying to wrap my head around tuning nitro engines.

The Rev

iTrader: (3)

.21's generlly eat more plugs then .12's. If the element is breaking, it's usually from pre-detonation or excessive compression. also, p3 sounds very hot for a 21. they usually use much colder plugs. try an os 8 and see if that helps........

Rick Vessell

iTrader: (10)

Jon,

The P3 is the hottest plug in the range. You might try a P4 or a P6 for hotter weather. Check the top of the piston and the head button, is there any pitting? Pre-detonation will kill plugs like you're describing. The plug wire will also be gray and pitted as well. Check those things first and then go from there. I have other things you can check but it's more involved. You can PM me if the first suggestions don't work out.

Socko

rc_alan

Since you're running 30% nitro and using it in a .21 motor... You should really be using only a warm plug on cold days and a cold plug during the Summer months... Switch to a OS P8 and re-tune your motor... You should be fine after that... If the weather in your area is a bit cold, then drop in a OS P7... You should only need to run a hot plug if your running 16% nitro or lower. P3 and P6's are hot plugs and are used mostly in small block .12's...

RC_Alan

20 SMOKE

iTrader: (103)

jon here is a chart and description of different plugs http://www.outlawrc.com/glowplugs.htm

Jon Kerr

iTrader: (17)

Thanks guys. One more question. When I go to a #8 and I'll need to re-tune, which way should I need to adjust. Leaner or fatter?

pitdog

your head shimms should add up to 0.6 mm for 30% even 0.7

Rick Vessell

iTrader: (10)

Jon,

You've got PM.

Socko.

Jon Kerr

iTrader: (17)

Back at ya. Thanks.