Timing and Fuel

[ironworker40]

I turned up the fuel screw 1 flat then I checked timing and I was at 7.4. When I set it last time I set it at 8.3. Will turning the fuel screw change it that much? Now I wish I checked it before turning up fuel. Also does moving the timing to 9 or 9.5 change exhaust temperature? Will winter vs summer fuel change timing?

 

[icanfixall]

Turning up the fuel has no effect to timing. It wont change but the exhaust temps will be hotter. As for winter or summer blend fuel I'm thinking the summer will burn very slightly hotter. The closer to retarded timing you get the hotter the exhaust will be because combustion heat is still making heat as the exhaust valve goes open. Ever run a gas engine really retarded? The exhaust pipe off the manifold will turn red hot quickly.

 

[ironworker40]

Turning up the fuel has no effect to timing. It wont change but the exhaust temps will be hotter. As for winter or summer blend fuel I'm thinking the summer will burn very slightly hotter. The closer to retarded timing you get the hotter the exhaust will be because combustion heat is still making heat as the exhaust valve goes open. Ever run a gas engine really retarded? The exhaust pipe off the manifold will turn red hot quickly.

Garry, so in your opinion you think that going from 8.5 to 9 - 9.5 will not raise egt but may lower it or stay the same, and if you went to say 7.5 it would raise it?

 

[IDIoit]

when i was -1 degrees, my EGT's would spike very quickly.
when i got it timed to 9, my EGT's take alot longer to climb, and it dont get over 1150 ,
when my truck was retarded i would have to lift @ 1200

 

[icanfixall]

Garry, so in your opinion you think that going from 8.5 to 9 - 9.5 will not raise egt but may lower it or stay the same, and if you went to say 7.5 it would raise it?

Yes. My testing has shown this to me correct. Diesel burn slow. The closer to top dead center timing creates plenty of heat leaving the combustion chamber out the exhaust valve. Too much heat on the valve edge can destroy it too.

 

[ironworker40]

when i was -1 degrees, my EGT's would spike very quickly.
when i got it timed to 9, my EGT's take alot longer to climb, and it dont get over 1150 ,
when my truck was retarded i would have to lift @ 1200

When you say spike quickly, how fast are you talking. I have the original ats pyro that came with the turbo kit back in 1994. It changes rapidly, almost as fast as the tach. I'm wondering if the all react that quickly.

 

[ironworker40]

http://vid621.photobucket.com/albums/tt295/ironworker40/IMG_0915_zpswis7n67j.mp4

Here is a video of egt gauge on highway from about 55 mph foot flat to floor up to about 75mph. Is the exhaust temp climbing normally? I think it changes fast, but I never had an egt gauge before.