When rebuilding diesel injectors,616,617and other earlier engines,one of the main questions that should be asked is how many miles on engine (injection pump).High mileage pumps,usually 200,000 miles and up are down on delivery.
Worn pump can cause hard or no start condition after installing new or rebuilt injectors,(set at new engine specs). Worse in cold temps. Would suggest injectors be set more towards middle of scale. Owners not to happy when engine started ok before .

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Injector up grade? Mbz mod.617 late injectors.The inner spring was made longer,pintel holder cap made shorter.Said to have better spring action (less bounce and vibrations) Less smoke. These are the ones I prefer.

The real key is BALANCED and properly cleaned injectors. Turbo = 135 BAR or 1,950 PSI and NON-Turbo is 115 BAR or 1,650 PSI. I know those numbers are not exactly correct, but the difference is so minimal. The FSM says its OK to have a variance of +/- 50 PSI. So, not sure if one is going to have a problem if they are properly balanced at 1,900 or 1,600, respectivley, versus 2,000 or 1,700. I do know that if you have one at 1,600, another at 1,700, et cet., then you have problems. I would not go below 1,900 for the Turbo and 1,600 for Non-Turbo. So, even at that level, you are still at the FSM by being +/- 50 PSI.

Can get higher delivery pressure by stretching out that one spring? Some pumps are having an adjustable spring and some older are not.
It's like a 2 piece banjo bolt leading to the first injector from the pump. Supposed to stretch it out to 25-27mm I think, because over time it has been compressed out of spec.
I have no imperial evidence that this is of any use. I just know I read it somewhere here before and I have a pump from 82 and one from 85 each have the different style of bolt.

Rusted out beat down 300d turbo 82' -- RIP
Nice body, tons of ridiculous mechanical issues - 300d turbo 82' /motor 85'

Under NO circumstances would I stretch that spring. One uses shims to increase the pressue and NOT stretching the spring. That spring would be incredibly difficult to stretch out anyway. I have shims ranging from .010 mm to 1.8 mm. A .10 mm shim will increase the pressue by an approximate 100 PSI. If you took a Turbo 135 Bar Injector, one could easily increase the pressure up to 3,000 + PSI but just adding a very common sized shim, e.g., 1 MM to what came in it anyway. However, I think you would be inviting real problems. The spray pattern looks the same BTW. I have played around with different shims and PSI and after 2,000 PSI, the pattern looks the same. I am sure the spray is somehow "finer" but you are looking at such minute differences, I think you will screw up your engine or pump. I am also sure you will end up breaking the pintle after a certain point with too much shims.

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Larsalan -- I think we are talking about 2 different things ... LOL

(08-02-2012 07:14 PM)larsalan Wrote:  Can get higher delivery pressure by stretching out that one spring? Some pumps are having an adjustable spring and some older are not.
It's like a 2 piece banjo bolt leading to the first injector from the pump. Supposed to stretch it out to 25-27mm I think, because over time it has been compressed out of spec.
I have no imperial evidence that this is of any use. I just know I read it somewhere here before and I have a pump from 82 and one from 85 each have the different style of bolt.

Referring to fuel injector not the fuel pressure regulator,but yes that spring does weaken and re stretching does help.
Do not stretch the injector spring.

Right right. Do not stretch the injector spring but, I am thinking that a higher pressure leading to all the 4/5 injector line loop maybe beneficial.

Rusted out beat down 300d turbo 82' -- RIP
Nice body, tons of ridiculous mechanical issues - 300d turbo 82' /motor 85'

(08-02-2012 07:13 PM)Greazzer Wrote:  The real key is BALANCED and properly cleaned injectors. Turbo = 135 BAR or 1,950 PSI and NON-Turbo is 115 BAR or 1,650 PSI. I know those numbers are not exactly correct, but the difference is so minimal. The FSM says its OK to have a variance of +/- 50 PSI. So, not sure if one is going to have a problem if they are properly balanced at 1,900 or 1,600, respectivley, versus 2,000 or 1,700. I do know that if you have one at 1,600, another at 1,700, et cet., then you have problems. I would not go below 1,900 for the Turbo and 1,600 for Non-Turbo. So, even at that level, you are still at the FSM by being +/- 50 PSI.

Mbz technical data book 1983: Engine 617.95 injection nozzle pressures
with new nozzle,or tips 135-143 bar-1935.9lbs-2050.6lbs.
Engine 615,616,617.91 115-123 bar -1649.1-1763.8lbs
One thousand lbs diff. from high to low. Could that be enough diff.to possible cause a hard or no start condition on a worn pump ? IN my experience it has and can. Just trying to help.
Used injector at least--617.95-120 bar others 100 bar.

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(08-02-2012 07:21 PM)Greazzer Wrote:  Under NO circumstances would I stretch that spring. One uses shims to increase the pressue and NOT stretching the spring. That spring would be incredibly difficult to stretch out anyway. I have shims ranging from .010 mm to 1.8 mm. A .10 mm shim will increase the pressue by an approximate 100 PSI. If you took a Turbo 135 Bar Injector, one could easily increase the pressure up to 3,000 + PSI but just adding a very common sized shim, e.g., 1 MM to what came in it anyway. However, I think you would be inviting real problems. The spray pattern looks the same BTW. I have played around with different shims and PSI and after 2,000 PSI, the pattern looks the same. I am sure the spray is somehow "finer" but you are looking at such minute differences, I think you will screw up your engine or pump. I am also sure you will end up breaking the pintle after a certain point with too much shims.

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Larsalan -- I think we are talking about 2 different things ... LOL

Nor would I stretch the injector spring but that was what occurred at some of the Mbz dealers before they received the shims. EASY to do with a pair of side cutters.Still wrong. By the way you have GREAT price and work on injectors.

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(08-02-2012 08:01 PM)larsalan Wrote:  Right right. Do not stretch the injector spring but, I am thinking that a higher pressure leading to all the 4/5 injector line loop maybe beneficial.

From my experience it helps.

(08-02-2012 08:47 PM)Hercules Wrote:  

(08-02-2012 07:13 PM)Greazzer Wrote:  The real key is BALANCED and properly cleaned injectors. Turbo = 135 BAR or 1,950 PSI and NON-Turbo is 115 BAR or 1,650 PSI. I know those numbers are not exactly correct, but the difference is so minimal. The FSM says its OK to have a variance of +/- 50 PSI. So, not sure if one is going to have a problem if they are properly balanced at 1,900 or 1,600, respectivley, versus 2,000 or 1,700. I do know that if you have one at 1,600, another at 1,700, et cet., then you have problems. I would not go below 1,900 for the Turbo and 1,600 for Non-Turbo. So, even at that level, you are still at the FSM by being +/- 50 PSI.

Mbz technical data book 1983: Engine 617.95 injection nozzle pressures
with new nozzle,or tips 135-143 bar-1935.9lbs-2050.6lbs.
Engine 615,616,617.91 115-123 bar -1649.1-1763.8lbs
One thousand lbs diff. from high to low. Could that be enough diff.to possible cause a hard or no start condition on a worn pump ? IN my experience it has and can. Just trying to help.
Used injector at least--617.95-120 bar others 100 bar.

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Sorry guys sure miss counted there,from lower numbers 300lbs.diff. still has happened a few times.Set the nozzles down 100lbs started fine.

(08-02-2012 07:21 PM)Greazzer Wrote:  Under NO circumstances would I stretch that spring. One uses shims to increase the pressue and NOT stretching the spring. That spring would be incredibly difficult to stretch out anyway. I have shims ranging from .010 mm to 1.8 mm. A .10 mm shim will increase the pressue by an approximate 100 PSI. If you took a Turbo 135 Bar Injector, one could easily increase the pressure up to 3,000 + PSI but just adding a very common sized shim, e.g., 1 MM to what came in it anyway. However, I think you would be inviting real problems. The spray pattern looks the same BTW. I have played around with different shims and PSI and after 2,000 PSI, the pattern looks the same. I am sure the spray is somehow "finer" but you are looking at such minute differences, I think you will screw up your engine or pump. I am also sure you will end up breaking the pintle after a certain point with too much shims.

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Larsalan -- I think we are talking about 2 different things ... LOL

Nor would I stretch the injector spring but that was what occurred at some of the Mbz dealers before they received the shims. EASY to do with a pair of side cutters.Still wrong. By the way you have GREAT price and work on injectors.

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(08-02-2012 08:01 PM)larsalan Wrote:  Right right. Do not stretch the injector spring but, I am thinking that a higher pressure leading to all the 4/5 injector line loop maybe beneficial.

From my experience it helps.