Originally Posted by
imrob
ok thanks so you would say if the motor i have came with a 2 mill and 1 mill shim i can use the one mill and not worry about pitting unless it was to lean as long as i had glow plug clearenace corret. So early cumbustion does not pit the motor which is what i read on another. and if i wanted a later one i can go too a two mill shim which would be better for fuel cause im still tying to find a race motor for my d8t i have a 427 and a mach2 .28 which are good but if they dont hack my large track i think of the b5 or os .25 but the price is high for os but i would like that power since it what im used too from my maxx.
no not quite........ you cannot just blindly start removing shims without knowing your head clearance.......doesn't matter one bit how many shims are under the head, what matters is what the clearance is...The ideal clearance for any given engine has many variables..such as oil content of the fuel, or temperature of glowplug, engagement RPM of the clutch, tuned pipe characteristics , vehicle weight and gearing..air density,humidity etc. etc.....As a rule you want to run the tightest clearance your setup will alow...however identifying what is or is not ideal does take some skill with tuning and listening to a engine.......... Pitting is definitely from detonation, tighter head clearance can make a engine more prone to detonating, but usually only because the fuel demands were not met for the tighter head clearance....I have run engines extremely tight without any signs of pitting...but I also know how to tune, run great fuels, and cool glowplugs............ In the end a great deal of performance can be found by adjusting the head clearance, but it is not something to me messing with if your new to nitro....not unless of course your willing to learn at the cost of possibly damaging a engine if you make a mistake.....