Cummins 6CTA8.3 Injection Timing

I know several shops that use a cam degree wheel bolted to the balancer. then no need to measure the balancer just bolt the wheel on and make a pointer. degrees position doesn't change by diameter when your going off the face instead of the side of the balancer
 

CARMAN

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Just read 15 pages and whaaat? The suspense was killing me! I have a large Cummins only shop down the street. Maybe I will stop in and ask about the turning up on the 8.3 and see what they say since I am now full of knowledge. Just no guts to try it on my own.
 

74M35A2

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There is another path to doing it. The injection pump timing can also be adjusted inside the pump by a calibration shop with a pump flow bench. You can pull the pump, and send it to a pump shop. Tell them it is currently timed at 8 degrees, and you want it timed at 16 degrees instead. They will make the change to the pump. Then you just install the pump using the 2 plastic push-in timing pins, already on the pump and engine. I think I was quoted $100 to have this done. Gravy.

Sorry I stopped on it. I’m changing engines instead of modifying my stock one.
 
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CARMAN

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Yes had seen that idea in the thread. Still got to get that brake drum thing worked out. Just been working on cosmetic stuff. Then performance next. Picked up some extras up in PA this week. I had seen someone in the thread ask about exhaust delete. Any issue with just replacing muffler with a straight pipe? Don’t really need the back pressure for down shift. I’m sure it will sound good like my 2500 Ram.
 

grendel

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What's all the boo-hah-hah about now? There are many trucks out there with 16+ degrees of timing... there are many ways to get it done. I love mine, but did way more than just timing.
 

mreuss222

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i have 4 inch to 5 inch under the cab with no muffler.
i also have a 2016 ram full delete no muffler. the dodge is not loud at all. the 5 ton is about at my limits for sound..
I cut open my stock muffler and cut the crap out of it and welded it back up. sounded good and egts dropped a bit. egts drop even more with straight pipe.
i would gut the stock muffler. or buy my old one ! I may put a resonator on the straight pipe to help with the drone.



Yes had seen that idea in the thread. Still got to get that brake drum thing worked out. Just been working on cosmetic stuff. Then performance next. Picked up some extras up in PA this week. I had seen someone in the thread ask about exhaust delete. Any issue with just replacing muffler with a straight pipe? Don’t really need the back pressure for down shift. I’m sure it will sound good like my 2500 Ram.
 

CARMAN

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I just run the MM3 programmer. Really wakes this truck up. Kind of scary. Sinister deletes and straight exhaust.
 

Csm Davis

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Yes had seen that idea in the thread. Still got to get that brake drum thing worked out. Just been working on cosmetic stuff. Then performance next. Picked up some extras up in PA this week. I had seen someone in the thread ask about exhaust delete. Any issue with just replacing muffler with a straight pipe? Don’t really need the back pressure for down shift. I’m sure it will sound good like my 2500 Ram.
I have a straight pipe on the wrecker and it is not terrible but if I were to change any others I would use a cheap straight through flow muffler.
 

Mos68x

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Been a couple years since the meat of this thread was written. Anyone have updates on timing changes and corresponding EGT/MPG values? I still haven’t done this myself yet, but with the new replacement IP I’m getting about 7.1mpg and around 1050egt flat and level at 55mph. Still gutless on a hill from a standstill though so I’m going to have to do a few mods i think.
 

4XDesign

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Been a couple years since the meat of this thread was written. Anyone have updates on timing changes and corresponding EGT/MPG values? I still haven’t done this myself yet, but with the new replacement IP I’m getting about 7.1mpg and around 1050egt flat and level at 55mph. Still gutless on a hill from a standstill though so I’m going to have to do a few mods i think.
I am planning on cranking my timing to the 12 to 14° range fairly soon. I will report back whenever I complete this.
 

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Jeepsinker

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If you haven't done so already, replace the overflow valve on the pump. They are notorious for failing and causing low fuel manifold pressure. All it is is a banjo bolt with a spring and ball bearing inside. The spring breaks or the ball gets pitted and they leak pressure by.
Look for a Torktec ofv-20. Thats what you need. I know it says it's for the 5.9L P7100, but it's the same. It's also preset for a little higher pressure. Don't waste your money on an oem replacement. They're junk.

This is likely the cause of your low power. It's the fitting on the pump that the fuel return line connects to.
 

Mos68x

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I am planning on cranking my timing to the 12 to 14° range fairly soon. I will report back whenever I complete this.
I’m actually going to bump mine up 2* and see what it does. Im still contemplating using my water pump from Snow performance to build the 300 psi needed for the spill port timing.
 

Jeepsinker

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The barrel to body seals in that pump won't hold 300 psi. Just to be clear; you're talking about feeding fuel to the pump inlet at 300 psi in oder to maximize fuel intake to each plunger when the spill port opens, correct?
 

Mos68x

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300-375psi is what the cummins book says, if you think it’s incorrect blame them, I’m just citing the book lol

edit; but I think that is to allow even the slightest opening in the valves to show up
 

Jeepsinker

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I haven't gone back to read the rest of this thread. Been a long time since I looked at it. I was thinking you were doing that to get more power, but now it seems like you must just be doing it for testing purposes. My apologies.
 

Russ Knight

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If you haven't done so already, replace the overflow valve on the pump. They are notorious for failing and causing low fuel manifold pressure. All it is is a banjo bolt with a spring and ball bearing inside. The spring breaks or the ball gets pitted and they leak pressure by.
Look for a Torktec ofv-20. Thats what you need. I know it says it's for the 5.9L P7100, but it's the same. It's also preset for a little higher pressure. Don't waste your money on an oem replacement. They're junk.

This is likely the cause of your low power. It's the fitting on the pump that the fuel return line connects to.
Where is this located on the pump?
 
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