CDI powerfull multi-spark

[Michael Farrugia]

Unfortunately there are no O2 sensors fitted,  But before we engine blew 
we put out the plugs and realised that the mixture was a bit week.  We 
increased the size of the jets but it seems the harm has already been 
done.  It was loosing a bit of performance when it got to 5000 on top 
gear , on lower gears performance was better.
I can understand that weak mixture can heat up the chamber but I have 
heard it from two sources that very powerful spark can melt the piston.  
Can this be true?
thanks
Michael

>> I have put a CDI which gives a fairly powerful multi-spark on a 2 
litre 
>>  Ford pinto engine.  This engine is tuned to go up to 8500 RPM.
>>  However after some runs the engine broke.  When we opend the engine 
up 
>>  we found that on piston was melted.  A friend of mine told me that a 
>>  powerfull spark may be the cause.  Has anyone encountered such a 
>>  situation and how can it be rectified.
>>  Thanks in advance
>
>That souinds more like (1.) lean mixture, or (2.) (less likely) 
retarded
>timing.
>  Either can cause combustion chamber temps to soar...But, retarded 
timing
>will cause a serious reduction in performance, which wasn't mentioned,
>so I'd wager the "lean-out" scenario is what took place...
>Do you have any data such as O2 or (?) readings?
>Mike V.
>


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