I need some help understanding short standard glow plugs

[mattvictor]

I just signed up to the site ,I'm a buggy racer who runs .21 engines, currently a picco evo 2 with a standard head. I dropped out of it for 2 years , and now that I'm racing again I just bought some glow plugs from hobby town . I purchase some o s plugs ,and they are shorter than the usual standard plug body , creating an odd shaped to the top of the combustion chamber . can anyone tell me what's going on here ? thanks a lot .

 

[w bill]

This is already in the engine and motor thread don't duplicate or rolex will yell at you.:

 

[mattvictor]

sorry bout double post..newguy here.

I won't do it again.