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Discussion Starter #1
Hi I have just put on a 12mm pump on my silvertop td42 now I was just wondering what would happen if you were a tooth out with the timing on the gears ?
As I have a loud rattle at about 1800 rpm
Fine under load just at that rev with light throttle to hold speed it’s make a loud rattle sounds
Cheers
 

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nissan
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the rattle is pretty normal of 12mm pumps under little load. id imagine if it was a tooth out it would run average.
ive had a couple of 12mm pumps sound like a can of bearings under no load around 2000rpm. sounds horrid but its fine.
 

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TD42 GQ
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You might try adding a little bit of 2 stroke to your tank next time you fill up. Some have reported quieter running as a result.
In my case with the old silvertop 10mm pump it made no difference at all. But, I've just fitted an 11mm pump which is noisier and this discussion has reminded me to give the 2 stroke another go. Thanks for that!
Here's the link to the 2 stroke thread. Seems its important to use mineral, not synthetic, 2T oil.
 

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im no guru on the subject but most of the rattle comes from a drop in case pressure and causes the timing to change considerably. i think it goes super advanced but once you load it up case pressure comes up and timing reverts to its designed timing curve.
 

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Dont put 2 stroke in your fuel for this issue.
Generally modded pumps will be setup to hold a certain amount of timing at light load, which is what you are describing.
This can a bit more pronounced when going from a standard or even a worn older pump that struggles to do this effectively and are virtually silent.
Might be able to quieten it down a little with some static timing adjustment.
Some pumps, depends on who built it, can be worse than others, but generally they will all do it to some degree.
 

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SUI GENERIS UTE
GQ Ute 1990 Silvertop
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In simple terms it's the other way around If you are looking at it with that perspective which isn't the full story. For this aspect under load the fuel element is pushing a lot of fuel so a bit lower case pressure, when you lift your foot you gain a tiny bit more case pressure with respect to RPM due to less fuel being pumped out of the 12mm plunger element. Keeping in mind the transfer pump which generates the case pressure is rpm dependent but remember there is a pressure limit which is governed by a relief valve. The timing piston is governed by case pressure and springs which being case pressure dependent is also rpm dependent.

So not really the problem here. Its more about where the governor is set for the little piston relief slide thingo against the governor leaver so it can allow the governor leaver to release back to low idle dependent on the rpm and the governor weight centrifugal position reducing the fuel injected to match the internal timing the engine needs for that amount of fuel in the cylinder to reduce that knock rattle.. But in essence it's more about you have a little to much internal timing for light throttle fuel loading or cruise loading for the amount of fuel being injected...

Trying to get bulk fuel out of a 12mm and still keep case pressure high enough to get these bulk fuel values what we want from the higher case pressure but trying to keep these case pressures stable and withing the pressure range we need to act against the timing piston for an ideal timing range we need for the engine to produce power torque and AFR at each different load and rpm point we want or need, is a big compromise. So we are always going to get a miss match somewhere away from the ideal at different load rpm conditions hence some times when the pump builder hasn't quite done his R&D properly for a street criteria TD you will get the resultant rattle at cruise loading. Very different from a racing perspective injector pump where rattle and light load criteria is not even in the consideration here or for that matter a dyno queen condition where its full throttle only.

All understandable though when we the public demand high fuel loading to produce those big dyno numbers many of us base our performance criteria off. Very difficult to have your cake and eat it with a high fuel load mechanical pump compared to full electronic systems when we want drivability and nice response with acceptable rattle in engine and pump for all conditions.

Hope thats written well enough to get some sort of understanding.

For a half fix solution you can keep reducing or retarding static timing if the internal timing isn't too far out of range to lower that part throttle rattle. You will usually loose a bit of torque/power and sometimes response depending on your turbo model and version. Some big flowing TurboCharger turbines will tolerate retarded timing for a bit more spool EGT/EMP for better response without loosing to much or any peak torque/power. By the same token you can reduce boost at light throttle load to reduce light load rattle but also you can just as well increase boost or density to do the same thing for a reduced throttle position if you still have throttle at your light load rattle point.

The point i am trying to get here is the pump builder might have designed his pump for a different turbo or did his R&D on a different turbo and setup from what you have which will effect your rattle condition to some point. Just a few things to consider for the whys so it might not be the pump builders total issue in the end. Considering induction system restriction or lack of, exhaust and manifold, intake manifold, injector crack pressures, etc etc on and on.
 

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OldMav, Will this type of rattle hurt the engine in any way? I had my 10mm pump built into an 11mm almost 2 years ago and mine has made this rattle sound the entire time. I'm sure it's either the bigger pump or bigger injectors i had put in.
 

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SUI GENERIS UTE
GQ Ute 1990 Silvertop
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To be honest i dont know, there isn't any evidence to suggest it causes piston or pump damage or any other damage.
It just isn't best practice and its annoying to hear.
 

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I have exactly as you described
And I'm trying to work out how the governer or throttle is working on my pump if it's just a standard type for example I progressively or put my foot to 1/3 or half or something at any rpm around 1900+ and it'll take off pretty quick but if I put my foot anymore it doesn't go much faster if at all and all it does is raise my egts this seems to tell me the timing is dropping or the fuel amount drops 2ccs at 3700rpm apparently can't remember if it was 130 or 150cc set or capable but since then I've played with it.
I'm wondering if the fuel screw might be set too high commanding too much or boost pin too deep or just bad governor setup

Sent from my A1601 using Tapatalk
 

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In simple terms it's the other way around If you are looking at it with that perspective which isn't the full story. For this aspect under load the fuel element is pushing a lot of fuel so a bit lower case pressure, when you lift your foot you gain a tiny bit more case pressure with respect to RPM due to less fuel being pumped out of the 12mm plunger element. Keeping in mind the transfer pump which generates the case pressure is rpm dependent but remember there is a pressure limit which is governed by a relief valve. The timing piston is governed by case pressure and springs which being case pressure dependent is also rpm dependent.

So not really the problem here. Its more about where the governor is set for the little piston relief slide thingo against the governor leaver so it can allow the governor leaver to release back to low idle dependent on the rpm and the governor weight centrifugal position reducing the fuel injected to match the internal timing the engine needs for that amount of fuel in the cylinder to reduce that knock rattle.. But in essence it's more about you have a little to much internal timing for light throttle fuel loading or cruise loading for the amount of fuel being injected...

Trying to get bulk fuel out of a 12mm and still keep case pressure high enough to get these bulk fuel values what we want from the higher case pressure but trying to keep these case pressures stable and withing the pressure range we need to act against the timing piston for an ideal timing range we need for the engine to produce power torque and AFR at each different load and rpm point we want or need, is a big compromise. So we are always going to get a miss match somewhere away from the ideal at different load rpm conditions hence some times when the pump builder hasn't quite done his R&D properly for a street criteria TD you will get the resultant rattle at cruise loading. Very different from a racing perspective injector pump where rattle and light load criteria is not even in the consideration here or for that matter a dyno queen condition where its full throttle only.

All understandable though when we the public demand high fuel loading to produce those big dyno numbers many of us base our performance criteria off. Very difficult to have your cake and eat it with a high fuel load mechanical pump compared to full electronic systems when we want drivability and nice response with acceptable rattle in engine and pump for all conditions.

Hope thats written well enough to get some sort of understanding.

For a half fix solution you can keep reducing or retarding static timing if the internal timing isn't too far out of range to lower that part throttle rattle. You will usually loose a bit of torque/power and sometimes response depending on your turbo model and version. Some big flowing TurboCharger turbines will tolerate retarded timing for a bit more spool EGT/EMP for better response without loosing to much or any peak torque/power. By the same token you can reduce boost at light throttle load to reduce light load rattle but also you can just as well increase boost or density to do the same thing for a reduced throttle position if you still have throttle at your light load rattle point.

The point i am trying to get here is the pump builder might have designed his pump for a different turbo or did his R&D on a different turbo and setup from what you have which will effect your rattle condition to some point. Just a few things to consider for the whys so it might not be the pump builders total issue in the end. Considering induction system restriction or lack of, exhaust and manifold, intake manifold, injector crack pressures, etc etc on and on.
Hey oldmav would you know why or is it common to extend the foot pedal travel as my pump guy took out the gq pedal plastic stopper to gain more travel I'm not sure if this is done for my high rpm fuelling when the pump has catched up in rpm pressure and load or something

Sent from my A1601 using Tapatalk
 

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Discussion Starter #11
Just as an update after getting the tune @ diesel pump Caboolture the rattle quieted down a bit. I asked the tuner there about the rattle and if it was and issue and much like old mav they there’s nothing to prove that it causes any damage.
although still annoying that bloody rattle.
thanks for the replies.
 
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