Attention: TDR Forum Junkies 
After seeing the 6 cracked pistons and one dropped valve seat in LEPage's engine, I am thinking that the rules have changed.
I mean, the ULSD has more cetane, which means it ignites faster.
What was once safe as far as EGT and timing advance, may no longer be the case. I have seen molten pistons before, which is caused by a short, quick, overfueling.
But 6 cracked pistons, with very little melting, speaks of long term knocking damage, which some people may not even be able to hear over the wind/muffler/stereo/tire noise at 70+ mph.
Higher cetane requires less timing advance to obtain the same combustion characteristics. So, until the manufacturers of the timing boxes respond, by dialing back the timing a little, be careful, and don't add cetane improver with a timing box. Use a lower timing setting, if you can.
(I only say this for the programmers/boxes, not the rokktech sensor, which is not advanced enough to cause damage, so don't PM me on that. ) The tone wheel mod depends on how far you advanced it, but again, if light knocking only occurs at low rpm/low loads, the likelyhood for damage is almost nil. It's the sustained high speed knocking that kills.
The EGT rule of 1200 or whatever was safe before, may need to be lowered a little with advanced timing, since the actual combustion temperature goes up with advanced timing, but the EGT stays the same. I think the valves are more sensitive to EGT, but the pistons/cylinders (including the oil film on the cyinders wall) are more sensitive to the peak and the average combustion temperatures. The peak temperatures may cause localized melting and cracking with an uneven firing injector, even if the average temperature/EGT looks normal.
Feel free to comment. :-{}
I mean, the ULSD has more cetane, which means it ignites faster.
What was once safe as far as EGT and timing advance, may no longer be the case. I have seen molten pistons before, which is caused by a short, quick, overfueling.
But 6 cracked pistons, with very little melting, speaks of long term knocking damage, which some people may not even be able to hear over the wind/muffler/stereo/tire noise at 70+ mph.
Higher cetane requires less timing advance to obtain the same combustion characteristics. So, until the manufacturers of the timing boxes respond, by dialing back the timing a little, be careful, and don't add cetane improver with a timing box. Use a lower timing setting, if you can.
(I only say this for the programmers/boxes, not the rokktech sensor, which is not advanced enough to cause damage, so don't PM me on that. ) The tone wheel mod depends on how far you advanced it, but again, if light knocking only occurs at low rpm/low loads, the likelyhood for damage is almost nil. It's the sustained high speed knocking that kills.
The EGT rule of 1200 or whatever was safe before, may need to be lowered a little with advanced timing, since the actual combustion temperature goes up with advanced timing, but the EGT stays the same. I think the valves are more sensitive to EGT, but the pistons/cylinders (including the oil film on the cyinders wall) are more sensitive to the peak and the average combustion temperatures. The peak temperatures may cause localized melting and cracking with an uneven firing injector, even if the average temperature/EGT looks normal.
Feel free to comment. :-{}
