Just a follow up on some Basic Don'ts of Nitrous Pistons... On the Motor
Tear down I found Two Major Problems... First Tom... your exactly right... I
burned a Piston rather then Fracturing it.... I did in fact Fracture several
other Pistons ( based on stress cracks in the Top of the piston catching my
fingernail ) but the basic cause was the Piston Thickness under the Exhaust
Valve pocket... Dave gave me a neat way to check them.... but after reading
the Spec sheet from Ross... I already understand that we took off .060 for
Valve clearence and we started with .116 under the exhaust valve.... there
by leaving us Just a Tick Less then the .125 minimum for Nitrous... OKAY
ALOT LESS.... .056? so it's my idea at this point that we were about to
smoke this hole in the Piston anyway due to the Lean condition of the Motor
Prior to the N2O hit and finally got the Piston to blow through when I hit
the button... No the Retard issue isn't going to let me off scott free.... I
still messed up and very probably caused this thing to fail absolutely....
rather then just burning the hole in the Piston... Who knows.... it's all a
guess.... I am just sharing what I learned... and Trust me I am sharing it
with my motor builder... he has a couple of lessons in this .... but I still
have Blind faith in his ability over mine.... Next Year I am going to build
my own motors... This year I still need to count on someone else...
Fun stuff.... Keith
Dave's Idea to check the Piston dome's thickness is to set a small rod with
a pointy end in a vise and then set a Magnetic stand up with a dial
indicator on top of it.... set to Zero....then fish the Piston in between
the two and measure any point on the dome.... See Dave you can't trust me
with anything you don't say not to Tell....
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