Pop Pressure vs Timing

Shambo

Shambo

Diesel Idiot
Joined
Dec 20, 2006
Messages
1,413
I know changing the pop pressure effects the timing. but is there a general rule of Thumb that changing the Pop pressure this much makes a effective timing change of this much?
 
I did a search function and saw what you referred me to and that is not the answer I was looking for so I asked!
 
thats pretty much it. like adam said there isnt really a rule of thumb on how much it changes timing. you would have to change pop off, line size, and dv's all at the same time to see much of a change. just changing pop off wont change your timing much if at all. plus you never specified how much you was changing it. if you from stock to .120 lines, full cuts, higher/lower pop off then you might see 3 to 5 degrees at the most.
 
Chevycummins said:
thats pretty much it. like adam said there isnt really a rule of thumb on how much it changes timing. you would have to change pop off, line size, and dv's all at the same time to see much of a change. just changing pop off wont change your timing much if at all. plus you never specified how much you was changing it. if you from stock to .120 lines, full cuts, higher/lower pop off then you might see 3 to 5 degrees at the most.
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What calculation is that based off of?
 
i dont have a calculation its an educated guess based off stuff i have read off this forum. if i had a timing light i would set down and test it all to come up with hard evidence, but from everything i have read its never been a significant change to even worry about unless you do a significant change then you might see enough of a difference to worry about.
 
Timing light has shown me that going from stock 285bar to 300bar with everything else the same was roughly 2* at idle....I could see it being less as the rack travel increases.....

Opinion only....not fact. Based on my truck, timing light, and setup....

Chris
 
Signature600 said:
Timing light has shown me that going from stock 285bar to 300bar with everything else the same was roughly 2* at idle....I could see it being less as the rack travel increases.....

Opinion only....not fact. Based on my truck, timing light, and setup....

Chris
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WOW, I started that thread for that info alone. I asked for people who have checked timing with a light to respond and everyone that responded has never used a light.:bang Thanks for clearing that up, it fits the guesstimate I read a while back of 10bar per degree of timing.

Delivery valve affect on timing? - Competition Diesel.Com - Bringing The BEST Together
 
There can't be a rule of thumb. Different cc output, cam ramp rate, line diameter, holders, dv's, etc all change pressure, rate of injection, and volume.
 
Signature600 said:
Timing light has shown me that going from stock 285bar to 300bar with everything else the same was roughly 2* at idle....I could see it being less as the rack travel increases.....

Opinion only....not fact. Based on my truck, timing light, and setup....

Chris
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Chris,
Thanks that was all I was looking for!
 
AHall said:
There can't be a rule of thumb. Different cc output, cam ramp rate, line diameter, holders, dv's, etc all change pressure, rate of injection, and volume.
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Exactly. Every pump is going to be different

Chris
 
I was asking for generally, and i got the general answer i was looking foe and about what i was expecting. So im happy

Sent from my SGH-T879 using Tapatalk 2
 
On a stock 215 pump 181's stock lines and 370 injectors that popped at 265bar+/- timed at 18*.
switched to 093 lines it dropped to about 17+/- at that point we bumped the timing up to 25* and verified it.
Then tried a set of 120 lines and lost 2*. went back to 093 due to loping/driveability issues.
Tried a set of full cuts and lost about 2* Went back to 181's, again due to driveability issues.
Later installed a set of 5x18 injectors set at 300 bar and lost 3*. went back to stock lines and picked up only 1*+/-.
All of this was checked with an adjustable digital light and blue point adapter module, off of a constant 0* TDC mark and pointer (was never removed from engine)
 
SuperSonic said:
On a stock 215 pump 181's stock lines and 370 injectors that popped at 265bar+/- timed at 18*.
switched to 093 lines it dropped to about 17+/- at that point we bumped the timing up to 25* and verified it.
Then tried a set of 120 lines and lost 2*. went back to 093 due to loping/driveability issues.
Tried a set of full cuts and lost about 2* Went back to 181's, again due to driveability issues.
Later installed a set of 5x18 injectors set at 300 bar and lost 3*. went back to stock lines and picked up only 1*+/-.
All of this was checked with an adjustable digital light and blue point adapter module, off of a constant 0* TDC mark and pointer (was never removed from engine)
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WOW where were you when I started my thread months ago??? :welcome:

Thats interesting cause i went to 191s and 5x16s pop set at 280 and it sure seemed like I lost timing. If I lost 3* im back to stock :doh: Time for a bump!

thanks for the info!
 
Gasoline Sucks said:
WOW where were you when I started my thread months ago??? :welcome:

Thats interesting cause i went to 191s and 5x16s pop set at 280 and it sure seemed like I lost timing. If I lost 3* im back to stock :doh: Time for a bump!

thanks for the info!
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Don't get caught up in the numbers and calculations. Your timing needs to be set where it runs best in the rpm range that you run it, regardless of what number that it is.
 
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