1st Generation Dodge Cummins 89-93 Discussion of 12 Valve 5.9 Liter Dodge Cummins Diesels with Rotary Injection Pumps

Timing bump?

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  #11  
Old 01-20-2010, 06:27 AM
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Originally Posted by stillcummin
thankyou for the lesson on pump timing it had nothing to do with internal cylinder pressure alls it explained is how a diesel works!but thank you again
Then you still haven't grasped how fuel injection timing impacts cylinder pressures.

Sorry to have wasted your time.
 
  #12  
Old 01-20-2010, 04:16 PM
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im aware of this but your saying timing alone (without extra fuel) will blow a gasket?I would think youd get to a point where your injecting into the flamefront and you can even accelerate
 
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Old 01-20-2010, 04:27 PM
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Enough timing even with stock fuel will do in a HG... A original factory gasket will take less abuse then a newly installed HG.

Point is case, with 1/8" timing my factory gasket with the head bolts re-tourqed to 135 ft/lbs lasted about 1 month running 60psi... A new cummins gasket with the head bolts torqued to 135 ft/lbs lasted a year so far... Oh and I was spraying a .082 jet of nitrous to it.

The point I'm making is that while 1/8" of timing most likely wont hurt a truck in good shape... It can push a truck with a hurt gasket over the edge... And at 200,000 miles the head gaskets are not once they once were... So yes, there is a chance that as little as 1/8" bump in timing can blow your head gasket, is it a good chance, no, but a chance.
 
  #14  
Old 01-20-2010, 05:31 PM
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Thank's fot all your great input,my old truck has over 200,000 miles so I am gonna leave the timing alone for now.I have enough stuff to fix!
 
  #15  
Old 01-20-2010, 06:05 PM
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dont let all this scare you away.The timing bump is an excellent mod for cooler temps and some more economic mpgs.It will really fly on the freeway too.thats what it did most for me.My .3mm static advance really opened up a door to freeway passing!
 
  #16  
Old 01-20-2010, 07:30 PM
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Originally Posted by 440warwagon
Thank's fot all your great input,my old truck has over 200,000 miles so I am gonna leave the timing alone for now.I have enough stuff to fix!
Bump it a 1/16" use teh line between the pump housing and teh timing case
 
  #17  
Old 01-20-2010, 07:30 PM
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Originally Posted by stillcummin
dont let all this scare you away.The timing bump is an excellent mod for cooler temps and some more economic mpgs.It will really fly on the freeway too.thats what it did most for me.My .3mm static advance really opened up a door to freeway passing!
Your EGT gauge shows less but you are leaving more heat on the piston.
 
  #18  
Old 01-21-2010, 10:56 PM
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hey i didn't mean to scare you i was just saying don't go overbord. 3/16" seems to work well for me, try an 1/16 or 1/8.
 
  #19  
Old 01-22-2010, 05:48 PM
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Thank's I'm gonna bump it an 1/8th tommrow!
 
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