Timing bump?
 

I see people talking about bumping up thier pump timing,how much does it help and is there a downside?

Up side: You will feel some more power and boost will drop slightly.

Down side: Engine will sound louder. You will have to stay out of it until the coolant temp goes over 100 degrees. This is because the KSB increases timming about 5 degrees until engine temp goes over 100 degrees. Too much timming advance can blow an "O" ring on the back side of the VE - pump then has to come out to replace that "O" ring.

I run about a day and half advance for about 10 tears and have had no problems other than better mileage.

Others will probably add more to this post.

Bob

Your EGT's will drop on your gauge but you will you will be "leaving" more heat on the piston. It is harder on your head gasket. You should see a MPG increase.

1/8" bump is a good place to start for a stock injected truck. Crossys son did a video that is that is very informative. Its in the sticky.

yea just don't go too far on the timing till your fueled pritty hard, i've seen a lot of people blow head gasgets right after the did a timing bump... a little extra goes a long way

Thanks to all,Im new to this diesel thing still trying to figure out what mods to do,so many options!

If you gonna blow a HG at stock fueling with a timing bump you sure will blow it with more fuel and teh same timing.

it seems theres alot of people on this site making claims that arent true.this information is misleading and has to stop!if you dont know about something dont speak or type.timing wont blow a o-ring!theres a regulator man.Internal pressure stays the same it just injects the fuel earlier at the injector!

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how many people have you seen?lets hear it.

Um . . .
 

Your statement perfectly illustrates those people. :argh:

Internal pressure is exactly what pushes around head gaskets. Specifically, Peak Combustion Pressures.




What is Injection Pump Timing 101

Ours is a four-stroke infernal combustion engine. It uses the heat of burning fuel to expand air. Said expansion pushes the piston, which turns the crank, blah, blah.


Stroke 1: Intake Stroke. Has the Intake valve open and the piston moving down thus allowing air in (ignoring natural induction / forced induction).
Stroke 2: Compression Stroke. Has the Intake valve closed and the piston moving up thus compressing the air.
Stroke 3: Power Stroke. Has the hot expanding air push the piston down.
Stroke 4: Exhaust Stroke. Has the Exhaust valve open and the piston coming back up, pushing the exhaust out.

Where does fuel injection timing come into this? Let's call it Injection Event Timing by the way. ;)

- To start with, the injection event is centered around Top Dead Center (TDC). Right there separating the Compression Stroke from the Power Stroke. If this were a gasser, we'd be talking about the ignition timing.
- In the case our injection pump. We have to inject enough fuel to provide the heat to expand the air enough, to provide the power we demand. All at enough pressure to overcome the cylinder's charge of compressed air, and still have enough pressure to finely atomize the fuel. To complicate this, we have a very small window of time to do it and have the energy of heat do useful work.

NOW . . . . TIME.

- The injection event takes time from the initial popping of the injector beginning the flow of fuel all the way till the end of the fuel delivery and closing of the injector's pintle valve. With our old-school mechanical pump, we're pretty-much stuck with the actual event's function time-frame.
- We can how ever set the injection event occurrence in relation to TDC.

Let's imagine the time the IP takes to inject the fuel occurs over a set number of crankshaft degrees rotation. Let's say it takes 20 degrees for the sake of conversation.

Now let's look a little hard at what happens over that 20 degrees:
~ The fuel first begins to spray into the hot compressed air. With milliseconds, there's enough to have the fuel spontaneously ignite.
~ The fuel continues to spray in, further heating the air.
~ The fuel stops spraying in.

All the while the building heat, is forcing the air to expand, pushing the piston.

Now, let's put that in with relation to the piston movement around TDC. Our goal is to synchronize the time it takes for the fuel to get in there, heat the air, and have said expanding air produce as much work as economically/mechanically possible.

- That fire driven expansion of air takes time pretty-much inline with the injection event time. It builds in pressure up to a peak level ~ Peak Combustion Pressure.
- We want to have that peak combustion pressure coincide with right at TDC give or take a little. All in the name of extracting as much work as possible.


OK fine. Get to the point . . . :scare2:

Referencing stock/OEM injection event timing . . .

ADVANCING THE TIMING:
- Allows more heat to stay in the power stroke, doing more work, That's why we typically see a bit more horsepower there. But it's at the expense of having the peak combustion pressures overpower the headgasket. The injection event actually starts some degrees before TDC. We're forcing it to occur even earlier. Our torque goes down a bit simply because the engine is now working harder to compress the charge-air, while the danged fuel is heating it up!
Further, EGT's go down. Remember our turbo chargers are driven by the hot exhaust gases, advancing the injection timing leaves less heat to drive the turbos, hence ~ less boost.

RETARDING THE TIMING:
- Allows less heat to stay in the power stroke, and be wasted as hot exhaust. That also means the engine doesn't have to work so hard compressing things, leaving more useful torque at the crankshaft. EGT's go up. The turbo will have more heat to drive it thus we see more boost.




There are a number of other things influenced by altering the injection event timing like emissions for example.

Did you know the intercooler wasn't added by Dodge to make the engine more powerful? It was added to reduce the charge-air temperature, which influenced peak combustion temperatures, all in the name of reducing oxides of nitrogen (an air pollutant).

Today's electronic injection systems allow very fine tailoring of the injection event itself as well as the timing. For example, a very small amount to fuel can be initially injected to just get the flame started with much less of the common diesel clatter. Once the flame is established, the remaining quantity to fuel is injected completing the event. So now you have those funny sounding , quiet diesels.


Hope this is more helpful than confusing. :hellox:


Oh, and this was brought to you by the color PURPLE. :tu:

ok i have three guys i can think of off the top of my head.... #1 a kid with a 90 like mine, hurd on a web sight it was good to crank the timing up.... shoved the IP against his head, head ended up at my work for o-inging two days later. #2 was a 97, big sticks some sort of race pump, kid brought the head into work said he blew the head gasket, asked what he had done to his truck, he mentioned he just advanced his truck to 28*, #3 one of my friends 01, got a new chip to stack on his edge, said it was more or less for timing advance and more fuel, lost his head gasget a mounth later... now the 24v may or may not have been just from timing. but the other two guys that had there head at work seems like too much advance sure helped to cause the head gasket failor. i may be wrong in that thought, but i was pritty sure advancing the timing caused the cylinder pressure to increase, thus being harder on the heead gasket.now i also am not saying that bumping it a little will hurt anything, just don't go crazy. thats all

BC847 i asked him to supply his knowledge of these blown headgaskets and of course all extreme cases.I though were talking about an 1/8"bump here.I see tons of guys take theyre stock timing and advance it without trouble.If your going to skip teeth and run extreme then thats what happens.I never argued that it raises cylinder pressure,but ive never seen an 1/8 bump take a head gasket!sorry!these guys you speak of are obviously modded through the roof and trying to extract every last drop of power,thats when you have to pay.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