GM 3,0 L Ignition

[TwoBallScrewBall]

Re: GM 3,0 L Ignition

I couldn't find it either, I was looking under "Ignition - EST". I decided to check under "Wiring Harness" and there it was.

 

[anesthes]

Re: GM 3,0 L Ignition

Detonation is NOT pre-ignition.<br /><br />Pre-ignition happens when the cyl temperature is too high which results in early combustion (long before the spark even thinks of lighting). What actually causes that a lot of the timing is RETARDING ignition timing. <br /><br />Detonation happens AFTER THE FUEL IS BURNED. The reason for detonation is because the fuel does not have enough octane to sustain the heat of the violent burn.<br /><br />What detonation does is increases cyl pressure greatly for a short duration of time, which causes the piston and rings to vibrate at 6400 Hertz. That is the tone you refer to as pinging.<br /><br />Another note on timing. Give a motor what it wants. Increasing spark advance, will increase cyl pressure, which will in turn increase power. However, the increases spark advance will require higher octane fuel. <br /><br />-- Joe

 

[affa]

Re: GM 3,0 L Ignition

Hi, and thanks to all off you!<br />Im starting to understand that using the specs for my old 140, is not the right thing even if its the same ignition.<br />I am wondering if the dwell Ive sat to 40 dg may be wrong as well (acc. to serv bull 11-95), there are maybe not dwell specs on this engine since its suppose to use the EST ignition which Ill have in place in a few weeks time, but untill then I like to make it work as well as I can.<br />Regards<br />Affa

 

[TwoBallScrewBall]

Re: GM 3,0 L Ignition

No dwell on an EST I don't think, since there are no points. <br /><br />Anesthes, thanks for the info. I always thought that detonation and pre ignition were about the same thing. I knew that both too advanced timing and too high compression/low octane could cause a pre-igniton scenario (i.e. with or without spark it could happen), but didn't know about the after-burn detonation you refer to. Thanks.