CDI powerful multi-spark

[Falb, John]

Never heard of a spark being able to do any damage. Sure the timing of the
spark can definitely cause problems, and a lean mixture will cause a piston
to melt if pushed that far. I would believe that there wouldn't be so many
people making CD ignitions if they caused peoples motors to melt. The spark
only ignites the mixture, the mixture is what caused your problems, it was
too hot.

John Falb 

-----Original Message-----
From: Michael Farrugia [mailto:mikefarr at hotmail.com]
Sent: Thursday, December 10, 1998 6:53 AM
To: diy_efi at efi332.eng.ohio-state.edu
Subject: Re: CDI powerfull multi-spark


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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