Tuesday, May 31, 2011

Unsatisfactory Condition Report

Unsatisfactory Condition Report or UCR as my retired RCAF friends and those serving in the Canadian Armed Forces will recognize the term as something, "not good "!              Caused by driver error.
 In our last run  at Speedweek 2010 we suffered an exhaust failure and a small fire resulted in critical wiring and hoses being cooked. The result was we never, started the engine until this spring. It took a small shot of ether to fire up and there was an unusual amount of white smoke. We decided to tear it down to investigate the problem. But first, at the suggestion of some  friends with diesel knowledge, we performed a "HIGH IDLE TEST" ,which I was not normally prepared to do but for the fact the engine had to come apart anyway. Now let me describe this high idle test, it just means that you open the throttle to see how many rpm it will turn. Not something I have even dreamed of doing with an engine, race prepared or not.
So, prior to tear down, Werner equipped with a laser tachometer and me managing the throttle,  proceeded to find out that the valves floated at 4780 rpm. Not high for a light weight gas motor but quite high for a heavy duty diesel. When it pushed oil out of the crankcase breather, we knew that there was a serious problem.


#3 Cylinder showing damage to piston and scoring of wall.
 

Evidence of Valve contact #1 during Hi Idle Test and detonation (melting piston)  .
 When we tore it down we found that during the run at Bonneville, I had fed it way too much nitrous for the available fuel at that moment. I also in frustration with the lack of speed, I held the nitrous buttons down for a long time instead of doing what I knew was the right thing, release the buttons instead I was trying different overdrive setting hoping it would take off. When  you add nitrous no increase  in power is evident  means no fuel. It is that simple!! My fault entirely. lesson two  don't listen to people that tell you to do what you think is just wrong, unloaded engine at full throttle is bad move!
Damage: 4 pistons to replace, 4 intake valves to replace, cylinders will have to be bored .020 oversize  and the cam shaft checked by COLT CAMS for damage.
I am embarrassed to admit all this but it is only the second time in all my racing days that I have lost an engine.
 Landspeed Louise warned me, "It is not like drag racing, Randy and your a rookie out here!" I agree.

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