glow plug

[jimmy45]

I have a .18 vertex engine running 20% nitro, while i was buying fuel i told the guy at the hobby shop i need glow plugs so he gave me an os Lc4 which is a long reach plug with medium heat range the engine runs fine with those plugs but i realized the stock plug was a short reach. My question is would my engine run better with a short reach and a hotter plug?

 

[mtaylortank]

if you have a manual at all it should be labeled in there to which plug should work better.. ( well sometimes it is in there)

 

[jimmy45]

It doesn't say in the manual what plugs to use

 

[w bill]

Use a med short a long could punch a hole in your piston.

 

[olds97_lss]

I'm guessing the long isn't hitting your piston, or you would already know.

The best/easiest way to tell if your plug is too long, take the head off and look at the dome on the head button/cooling head from the inside with the plug in it. If the plug extends past flush, it's too long. Having the plug as close to flush with the surface of the dome helps avoid causing excess turbulence inside the combustion chamber when it's running, which helps promote smoother, more consistent running.

This is the underside of the head/head button:

Notice how the plug is flush with the surface of the dome/concave area. That's what you want.