hey, i was just wondering if you have to make any modifications to your engine when removing shims. from what i understand, you should switch your glowplug one that is one number colder (ie: #3 plug to #2). you need a colder plug because the glow plug is lower, so it ignites the fuel earlier, by using a colder one you delay the detonation and they balance out to keep it in tune. is this true? some guys at my local hobby shop told me that after i told them i removed my shims.

removing a shim increases compression, which in turn raises the heat and can cause pre-ignition, so you MAY need a cooler plug. depends on how close the engine/fuel combo was before you removed it though, there is no rule that says you have to change plugs...