- Thread starter pjbrown
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JOHNNYfromMI
Member
If you look close you will notice ALL the injector lines are the same length. Has to be that way for the motor to run even.
2cylpartsinfo
Member
Leave them all the same length. If one is shorter its cylinder will be injected too soon.
Factoty engineers spend lots of time designing lines and support brackets. For the most part they do a pretty good job as you don't hear of many broken lines.
Factoty engineers spend lots of time designing lines and support brackets. For the most part they do a pretty good job as you don't hear of many broken lines.
40 years ago ,I was under the impression that
all lines in a set were the same length, but a
few years ago a fellow brought me a bundle of
new inj line to duplicate a set for a cockshutt
tractor. Too my surprise each line was a
different length . I made 2 sets of forming dies
to bend the different size loops and bends.
george
Billy Shafer
Well-known Member
Yes there is. It will power the money out of your wallet to repair the damage.
Bob Huntress
Member
The lenth of the injector line makes no difference, but obstructing the fuel return line from the injector.
Bob Huntress
Member
When I say that the lenth makes no difference, there is a minimum volume of line, though it rarely is an issue. The volume of the injector line must excced twice the amount of fuel that is injected into the cylinder during a single stroke, but, you can see that is almost never going to become an issue.
The length of the fuel lines will MAKE NO DIFFERENCE in power, timing or anything else.
Pascal's law simplified: increasing the pressure at any point in a confined fluid, there is an equal increase at every other point in the container, i.e., any change in pressure applied at any point of the fluid is transmitted undiminished throughout the fluids.
Now in everyday terms. The injection pump creates a pressure spike at one end of the line. The injector at the other end is just a fancy pop off valve with an outlet nozzle. So with no air in the line, the pressure is increased at the injection pump end and is transmitted to the injector through the fuel/fluid. This pressure overcomes the injector pop off point and the injector then injects the fuel.
Pascal's law is why a hydraulic jack works. The smaller cylinder under the handle creates a high pressure that is transfered through the fluid/oil to the larger lift cylinder.
Pascal's law simplified: increasing the pressure at any point in a confined fluid, there is an equal increase at every other point in the container, i.e., any change in pressure applied at any point of the fluid is transmitted undiminished throughout the fluids.
Now in everyday terms. The injection pump creates a pressure spike at one end of the line. The injector at the other end is just a fancy pop off valve with an outlet nozzle. So with no air in the line, the pressure is increased at the injection pump end and is transmitted to the injector through the fuel/fluid. This pressure overcomes the injector pop off point and the injector then injects the fuel.
Pascal's law is why a hydraulic jack works. The smaller cylinder under the handle creates a high pressure that is transfered through the fluid/oil to the larger lift cylinder.
Well, I guess I can tell the engineers that I work for at Stanadyne that we can make all engine line lengths the same. Oh, and also tell my one customer who wants 18.3" lines and the other that wants 23.8" lines it doesn't matter what length to make them, even though they are both for the same DE10 four cylinder electronic pump).
If you cut inches off a line it WILL change timing. The lines are full of fuel while the engine is running and: for a given amount of fuel that is pumped, the same amount comes out the other end, which is Pascal's law. Changing the length doesn't effect HOW MUCH will be pumped, but HOW LONG it takes to get from one end of the pipe to the other.
If you looked at my pump at work while it's on the test stand, you will find pressure transducers on the discharge fitting of #1 cylinder on the pump (I will call it PE for pump end pressure), another on # 1 cylinder injector (I will call it NE, nozzle end pressure) and an instrumented # 1 injector which will show a trace of the needle being open (NL, which is short for needle lift).
There is a thing called line delay when dealing with a injection pump and its injectors. This is the time it takes for the fuel to enter the line at the pump and it to open the needle in the injector.
What I will do is measure the time it takes from PE to the time it takes for NL opening. This is measured on an oscilloscope in milliseconds. If you chop 3 inches off an injection line, your line delay has just gotten shorter (remember the lines are still fill with fluid and according to Pascal's law, the same amount will be displaced, but is this case, it just doesn't take as long to come out the other end).
An example: say it takes 15ms (milliseconds) from PE to the start of NL (needle lift) with 23.8" lines, it might only take 10ms using 18.3" lines. Why, because there is 5" of injection line now gone so it gets from the pump to the nozzle faster. Remember the line ID's are the same, so Pascal still holds true.
Sure it might seem like a lot, being only a few milliseconds, but it can add up to 5+ pump degrees in timing authority; that could lead you to be pumping over the nose of the cam, or on the base circle of the cam, both of which are bad.
This is why calibrating injection line lengths are specified by both SAE and ISO to be 25.5" long, with an ID of .0625".
Another point, by changing the line length, you can effect the afterwave going back through the line when the needle is shut. That can effect line pressures, just like changing line ID.
Do you want to debate changing line ID's?
And yes, that too makes a difference. Some of the different line ID's I've used for various customers while at Stanadyne (ID's in inches): .055, .0625, .067, .072, .093 and .098.
Changing the ID's will effect residual pressures which stay in the lines between pumping events. Typically, I will change other things to get the residual pressures I want first before changing line ID's. This again will require pressure transducers and an oscilloscope.
bob
If you cut inches off a line it WILL change timing. The lines are full of fuel while the engine is running and: for a given amount of fuel that is pumped, the same amount comes out the other end, which is Pascal's law. Changing the length doesn't effect HOW MUCH will be pumped, but HOW LONG it takes to get from one end of the pipe to the other.
If you looked at my pump at work while it's on the test stand, you will find pressure transducers on the discharge fitting of #1 cylinder on the pump (I will call it PE for pump end pressure), another on # 1 cylinder injector (I will call it NE, nozzle end pressure) and an instrumented # 1 injector which will show a trace of the needle being open (NL, which is short for needle lift).
There is a thing called line delay when dealing with a injection pump and its injectors. This is the time it takes for the fuel to enter the line at the pump and it to open the needle in the injector.
What I will do is measure the time it takes from PE to the time it takes for NL opening. This is measured on an oscilloscope in milliseconds. If you chop 3 inches off an injection line, your line delay has just gotten shorter (remember the lines are still fill with fluid and according to Pascal's law, the same amount will be displaced, but is this case, it just doesn't take as long to come out the other end).
An example: say it takes 15ms (milliseconds) from PE to the start of NL (needle lift) with 23.8" lines, it might only take 10ms using 18.3" lines. Why, because there is 5" of injection line now gone so it gets from the pump to the nozzle faster. Remember the line ID's are the same, so Pascal still holds true.
Sure it might seem like a lot, being only a few milliseconds, but it can add up to 5+ pump degrees in timing authority; that could lead you to be pumping over the nose of the cam, or on the base circle of the cam, both of which are bad.
This is why calibrating injection line lengths are specified by both SAE and ISO to be 25.5" long, with an ID of .0625".
Another point, by changing the line length, you can effect the afterwave going back through the line when the needle is shut. That can effect line pressures, just like changing line ID.
Do you want to debate changing line ID's?
And yes, that too makes a difference. Some of the different line ID's I've used for various customers while at Stanadyne (ID's in inches): .055, .0625, .067, .072, .093 and .098.
Changing the ID's will effect residual pressures which stay in the lines between pumping events. Typically, I will change other things to get the residual pressures I want first before changing line ID's. This again will require pressure transducers and an oscilloscope.
bob
Diesel fuel compresses slightly under high pressure. The longer the line, the longer it takes for the injection pulse created at the pump, to make it out the injector nozzle. Thus the reason for keeping all lines same-length (or close). If you shortened all your lines, firing time would be slightly advanced equally. If you shortened only one line, timing would be advanced on one cylinder only.
Length of lines certainly does make a difference. Injection systems gets "injection lag." That is the time difference between when the pressure spike is created at the pump . . . and when injection actually takes place in the engines combustion chamber (or pre-combustion chamber).
When an engine is designed, injection-lag is taken into account and the pump timing specs allow for it. Some makers give you timing specs to be checked AT the pump, while others IN the combustion chamber.
All this is why there is big difference in timing specs if using a diesel line-pulse timing light instead of a luminosity sensor. The former measures injection BEFORE the injector, and the latter measures AT the time of injection. There is often a difference of 3-4 pump degrees (that"s 6-8 engine degrees for a 1/2 engine speed rotary pump).
Length of lines certainly does make a difference. Injection systems gets "injection lag." That is the time difference between when the pressure spike is created at the pump . . . and when injection actually takes place in the engines combustion chamber (or pre-combustion chamber).
When an engine is designed, injection-lag is taken into account and the pump timing specs allow for it. Some makers give you timing specs to be checked AT the pump, while others IN the combustion chamber.
All this is why there is big difference in timing specs if using a diesel line-pulse timing light instead of a luminosity sensor. The former measures injection BEFORE the injector, and the latter measures AT the time of injection. There is often a difference of 3-4 pump degrees (that"s 6-8 engine degrees for a 1/2 engine speed rotary pump).
Tx Jim
Well-known Member
- Location
- Coyote Flats, Texas
bob15
Does your statement apply to older style inj pumps & lines? I checked on the spec's(no lengths stated) on JD website for my JD 4255 and found 3 different inj lines weighed 3 different weights.
Part Number: RE47414
Part Price: 52.51 USD
Description: LINE, FUEL INJECTION, NO. 1
Weight 0.46 LBS 0.21 Kg
Part Number: RE47418
Part Price: 52.51 USD
Description: LINE, FUEL INJECTION, NO. 5
Weight 0.42 LBS 0.19 Kg
Part Number: RE47419
Part Price: 52.51 USD
Description: LINE, FUEL INJECTION, NO. 6
Weight 0.49 LBS 0.22 Kg
The honest answer to why the weights are different for the 3 different lines, I do not know. I could try to BS my way through it, but I don't play that way. Does the weight include shipping/packaging? Granted the difference in weight is about an ounce, and the line OD is probably 1/4" (6mm is the other line OD being used) with and ID of .0625" i cannot come up with a good answer. Bending a line isn't going to add weight either. I could inquire tomorrow and ask a couple of my co-workers if you want me to......
Even with older engines, they are the same length. That is why lines are bent crazy-line. Besides trying to be neat looking for cosmetic purposes, the engine manufacturer is also "using" the extra length up by adding bends. If you look up RE47419 (deere 4255 line, cylinder # 6) it is pretty much a straight shot from pump to injector (looking at the Deere parts picture). Look at cylinder # 1 (RE47414) and how many bend there are. The bends are there some they can "use up" the extra line length.
When we make lines, a horizontal band saw is used and the lengths are typically within a 1/32" of an inch. All our stuff is bend by hand and on some dyno engines, the line transducers are not "in-line", but rather silver soldered onto the line itself.
Hope this helps....bob
Even with older engines, they are the same length. That is why lines are bent crazy-line. Besides trying to be neat looking for cosmetic purposes, the engine manufacturer is also "using" the extra length up by adding bends. If you look up RE47419 (deere 4255 line, cylinder # 6) it is pretty much a straight shot from pump to injector (looking at the Deere parts picture). Look at cylinder # 1 (RE47414) and how many bend there are. The bends are there some they can "use up" the extra line length.
When we make lines, a horizontal band saw is used and the lengths are typically within a 1/32" of an inch. All our stuff is bend by hand and on some dyno engines, the line transducers are not "in-line", but rather silver soldered onto the line itself.
Hope this helps....bob
Tx Jim
Well-known Member
- Location
- Coyote Flats, Texas
bob15
I checked late model JD 4020 and the weight differences are similar to the 4255
Part Number: AR51194
Part Price: 31.24 USD
Description: LINE, FUEL INJECTION, #1
Weight 0.46 LBS 0.21 Kg
Part Number: AR51199
Part Price: 35.96 USD
Description: LINE, FUEL INJECTION, #6
Weight 0.51 LBS 0.23 Kg
I've been aware that the injector lines leading to injectors that were closer to the inj pump had more bends/crooks and sometimes circles.
I've got another question and I'm not arguing simply asking. If the injector line is full of fuel(no air) and injector valve shuts off to trap the fuel in the line then why if lines were different lengths it would affect timing IE it's not the same as shooting a bullet(bullet has to travel FPS) as fuel is already at the target(injector)?Thanks,Jim
I'm not sure if I understand the question, please correct me if I'm wrong. Remember the bullet doesn't leave the barrel instantly, it does take time, granted it's in micro or milliseconds. Kinda like which barrel will have the bullet leave first, a 16" barrel or a 26" barrel.
The injection pump itself is timed to the engine, so if the pump is designed to deliver fuel at say 2° BTDC (injector needle lift is just beginning). If the lines are shortened, the fuel will begin to lift the needle 8° BTDC. Now this is messing the pump to engine timing up. If the injection line is lengthened, the amount of time for the displayed fuel to move down the injection line might cause the needle to lift 10° ATDC.
Keep in mind, when fuel is pumped, the fuel isn't instantly displaced. It seems it because the the time is so fast, typically in milliseconds. but there is a lag.
Imagine 2 garden hoses, one 50' and one 75' long, both filled with water and baking in the summer sun. Both nozzles are opened at the same time. Which one will get the cold water (out of the well) first (facet pressure being the same)? The shorter one will see cold water first.
If only one or two lines are shortened, the engine performance will suffer because some cylinders are being sprayed with fuel and "igniting" or "firing" too soon, maybe while the piston is only halfway up its compression stroke (an exaggeration for visual help). And then the others are firing while the piston is already past compression, thus not a very good running engine, if it runs. Idle smoothness will suffer and raw unburnt fuel will be probably wind up in the engine oil if the engine runs long enough due to incomplete burning.
On my other posting, I mentioned over the nose of the cam. I am referring to the pump cam, NOT the engine cam. This could happen on electronic pumps, if the pump timing (computer program) was reset or adjusted to account for new line length. I don't believe I made myself clear on that one. Sorry about that.....sometimes one will forget the audience he is talking to might not understand my babblings...lol
Did I answer the question? If not, please let me know.
bob
The injection pump itself is timed to the engine, so if the pump is designed to deliver fuel at say 2° BTDC (injector needle lift is just beginning). If the lines are shortened, the fuel will begin to lift the needle 8° BTDC. Now this is messing the pump to engine timing up. If the injection line is lengthened, the amount of time for the displayed fuel to move down the injection line might cause the needle to lift 10° ATDC.
Keep in mind, when fuel is pumped, the fuel isn't instantly displaced. It seems it because the the time is so fast, typically in milliseconds. but there is a lag.
Imagine 2 garden hoses, one 50' and one 75' long, both filled with water and baking in the summer sun. Both nozzles are opened at the same time. Which one will get the cold water (out of the well) first (facet pressure being the same)? The shorter one will see cold water first.
If only one or two lines are shortened, the engine performance will suffer because some cylinders are being sprayed with fuel and "igniting" or "firing" too soon, maybe while the piston is only halfway up its compression stroke (an exaggeration for visual help). And then the others are firing while the piston is already past compression, thus not a very good running engine, if it runs. Idle smoothness will suffer and raw unburnt fuel will be probably wind up in the engine oil if the engine runs long enough due to incomplete burning.
On my other posting, I mentioned over the nose of the cam. I am referring to the pump cam, NOT the engine cam. This could happen on electronic pumps, if the pump timing (computer program) was reset or adjusted to account for new line length. I don't believe I made myself clear on that one. Sorry about that.....sometimes one will forget the audience he is talking to might not understand my babblings...lol
Did I answer the question? If not, please let me know.
bob
buickanddeere
Well-known Member
No. Did somebody tell you this ?
Tx Jim
Well-known Member
- Location
- Coyote Flats, Texas
Maybe my bullet in FPS doesn't apply to this situation.
Injection systems I'm referring to are not electronic but manual.
Ok I see no correlation between the 2 garden hoses and which gets cold water "first" and the injection lines because one hose is 50% longer than the shorter hose. The injector line isn't trying to deliver "cold" fuel just "fuel". It appears to me that if the fuel is in the line and the injection pump sends fuel to that line then a working injector should spray fuel.
I suppose I can't see the forest for the trees.
My idea of the water hose is that with a hose full solid of water(like an injection line), the longer hose will take longer to displace the warm water. even if it is only 3 feet difference.
More importantly, if fuel goes in one end and comes out the at the nozzle and nobody has modified the line, you will be a happy camper when the engine is running.
To the original poster, don't mess with line lengths. It just isn't worth it.
More importantly, if fuel goes in one end and comes out the at the nozzle and nobody has modified the line, you will be a happy camper when the engine is running.
To the original poster, don't mess with line lengths. It just isn't worth it.
Owen Aaland
Well-known Member
I have seen the difference in timing from one end of an injection line to the other end on an IH 1086.
IH release an electric timing light about the time those tractors were new. It used a pressure transducer to trigger the light. The transducer was to be installed at the injector. After using it a few times I decided it would be easier just to put the transducer in the line at the pump. It changed the triggering of the light by about 8°.
IH release an electric timing light about the time those tractors were new. It used a pressure transducer to trigger the light. The transducer was to be installed at the injector. After using it a few times I decided it would be easier just to put the transducer in the line at the pump. It changed the triggering of the light by about 8°.
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