How I do when calibrating a pump in testbench
How I do when calibrating a pump in testbench
Hi folks.
There are a lot of misunderstanding regarding how to do to, or whats beeing done when a pump is up in the testbench.
I have seen it on varios forums, and the ingenuity is BIG in this area.
Therfore I shall put down in words what I do, and what I need to have in my workshop for getting a good result.
In this i´m not thinking "outside the box", this is a regular calibration according to the testsheet.
First of all, testbench setup.
Calibration fluid ISO standard, NO DIESELFUEL in a testbench.
Why? Because diesel has warios viscosity.
Calibration fluid is 4-6 centistoke in all machines worldwide and testsheets are depending on the ISO standard.
If you take a measuring with diesel, it will be wrong
Injectors: There are a lot of different testinjectors, different nozzles, pressure springs, holders etc.
Around 40-50 different setups, Engine fabricants is the one that decide What injector and what pipe to use for just this pump.
In the testsheet I se which injector to use. If I have wrong injectors, the result will be bad.
Pipes, Same here, 600x3x6, or 600x1,5x6, 1000x3x8 etc etc, Wrong pipe and you have wrong amount of fuel.
For example, drive a pump with 600x3x6 pipes, BUT the testsheet says 600x1,5x6 = Do it again and do it right.
Engine in machine, 10 or 15 hp or moore, It depends what kind of pump there is, but for stabilisation on a 12 cyl P-serie you need a 15 hp engine.
Pump in bed, First of all, prestroke.
No 1 cyl ( or the one that testsheet says) pressure in, app 25 bar, open the injector owerflownut so that fluid comes all time, push the pump manual until you have "fuel cutoff"
There is the start of injection time.
testsheet tells me how big lift on camshaft, what rackposition in mm it shall bee.
If something dont is OK, Adjust.
After that, all the other cylinders to check that you hav the correct degrees between injections. ( ex 1-5-3-6-2-4 is 0-60-120-180-240-300 )
After that, start up machine, inletpressure according to testsheet.
Basic adjustment. ( Note this is an example only.)
Testsheet says.
700 rpm, racktravel 12,0 mm, fuel 80cc/1000 stroke Spread between lines 4cc
Adjust everything so it is OK, after that a lot of checking points, high rpm Low idle Boost on, boos off, boos half way etc etc. All the checking points have the same demands, RPM, rack, fuel boost, tourqecontrol etc.
Up to 50 different tests can be done before it is ready to go in the engine, But then, after that I know the engine will work OK.
This is a brief how I do, if anyone has any question, feel free to write it down in the topic and I shall try to answer.
NOTE i´m from Sweden, so if there is a lot of wrongspelling, dont shoot me
Thanks so much for taking your time to post this...this will be valuable for those of us who are able to understand it. Of course this is excluding myself. Thanks again!
Hi Thanks for interesting info.
Can you install the 7,5mm Floyd(Tomnik) elements in a Mercedes OM603 Bosch M pump? I guess the testsheet for that pump would be worthless since this will be a custom setup?
Wouldn't it be best to use the injectors and the injector lines that are going to be used in the car when you calibrate the pump? I mean for this specific custom setup
This is very informative, thank you for taking the time to put it together!
Beautiful stuff I must say. Keep it going...
Thanks Göran for posting this. Your experience is valuable.
Looking forward to seeing more of your stuff!
.
(04-01-2011, 01:04 PM)erling66 Hi Thanks for interesting info.
Can you install the 7,5mm Floyd(Tomnik) elements in a Mercedes OM603 Bosch M pump? I guess the testsheet for that pump would be worthless since this will be a custom setup?
Wouldn't it be best to use the injectors and the injector lines that are going to be used in the car when you calibrate the pump? I mean for this specific custom setup
Ofcourse I can, the only problem is that I cant get the 7,5 mm element from Tomnik.
Regarding the lines, Its not possible to put them up in the machine, for first you will crack them, second is that its the engine manufactor that decides what kind of testequippment that should bee used.
If I use the original lines, the pump will show wrong walues.
(04-01-2011, 01:04 PM)erling66 Hi Thanks for interesting info.
Can you install the 7,5mm Floyd(Tomnik) elements in a Mercedes OM603 Bosch M pump? I guess the testsheet for that pump would be worthless since this will be a custom setup?
Wouldn't it be best to use the injectors and the injector lines that are going to be used in the car when you calibrate the pump? I mean for this specific custom setup
Distributor pumps. Mechanical Bosch VE / VA
Teststand is basic as in the first topic, however there is a few things that are different.
Prestroke, Inlinepump I use 25 bar, Rotarypump type Bosch nedds just a flow, maybee 0,1 bar inlet pressure.
In the plug inbetween the valveholders, a dial indicator is put in. Pump in low deadpoint, fuel is comming out from the adaptor, push the pump in rotarydirection until fuels cut off. Normally 0,28-0,32 mm of stroke BUt its the testsheet that decides what measure there should bee.
Some pumps dont demand this, that is beacause you have a exact mounting dimension ( right there?) when pump is set together.
If not correct, adjust with shimms under the piston to get the right result.
If this is not OK, the pump timing will be wrong.
Example of correct timing in pump, Prestroke 0,30 mm, dial indicator in pump when mounting 0,90 mm @engineTDC. Difference between prestroke 0,30 and mounting measurment 0,90 is 0,60 mm, and on 0,60 mm the pump goes app 4 degrees. 4 pumpdegrees is 8 engine degrees and that is the alphaangle ( pumpsetting.)
NOTE HERE The 4 degrees is different depending on the shape on the camplate, this just an example to show whats happening.
If prestroke is wrong, let say 0,45 mm, the mechanic that mounts the pump doesent know this, he puts the pump acccording to his papers, 0,90 mm. Starts it up and it runs like shit. Why? The pump timing is correct he says,YES BUT the internal timing inside the pump is wrong.
Lest take a look
0.45 prestroke, 0,90 mounting difference is 0,45mm, app 2,5-3 pumpdegrees 5-6 engine degrees, the engine is to late in injection and will smoke blue, lack of power etc.
That is why prestroke is important.
Just to put in a distributor head or a element without this is nothing that a serious dieseltech will do.
However on the internet and on different kind of forums there is no big deal, just do it.... I read it and smiles a bit....
When driving pump in testbech I check rpm, WOT Advance piston movment, inlet pressure, house pressure, fuelflow transferpump pressure and owerflow value at different rpm etc etc. All according to testsheet
The temperature on the calibrating fluid is to bee 40 degrees celsius always, therfore we have a cooling/ heating system in the maching. Forgot that in my firs topic regardin the inlinepumps.
NOTE In some cases theer is the returnflow that should be mesaured, then it is up to 65 degrees, but that is normally VP37 pumps, I come back to those later on in this topic if anyone is intrested.
Advance is either from rpm, higer rpm higher advance, but some pumps has the LLA. Light Load Advance, that is when you have light load ( app 30-40%) the advance goes a bit early.
Low idle, high idle increase of fuel at start etc, around 20-30 different tests before it is ready for the engine.
Often when a VE serie is calibarted we use the "enginge close" parts, That is special injectors with 130 bar opening pressure, short lines, just to come as close the manufactors demands.
Hope that this can bee of intrest for you.
(04-02-2011, 01:07 AM)dieselmeken Ofcourse I can, the only problem is that I cant get the 7,5 mm element from Tomnik.
Regarding the lines, Its not possible to put them up in the machine, for first you will crack them, second is that its the engine manufactor that decides what kind of testequippment that should bee used.
If I use the original lines, the pump will show wrong walues.
(04-02-2011, 01:07 AM)dieselmeken Ofcourse I can, the only problem is that I cant get the 7,5 mm element from Tomnik.
Regarding the lines, Its not possible to put them up in the machine, for first you will crack them, second is that its the engine manufactor that decides what kind of testequippment that should bee used.
If I use the original lines, the pump will show wrong walues.
A bend introduces a flow restriction, that has to be compensated for. So just because it's the same linear length does not mean it will flow the same.
My guess is that the manufacturer adresses this with Bosch, and they work out a proper test plan based on the differences between the test bench system and the actual motor.
(04-02-2011, 04:15 AM)300D50 My guess is that the manufacturer adresses this with Bosch, and they work out a proper test plan based on the differences between the test bench system and the actual motor.
Thats correct erling66 What I wrote down was the standard setting procedur. When it comes to special pumps I will have to think "outside the box", and that is no problem for me.
I have been building special pumps for some 15 years now, and have build up a lot of expereince around this area during this time.
From the MB123 serie there was a company in Sweden called STT that build turbokit for the 4 & 5 cyl engine. The pump should bee tuned up in a testbench after STT testsheet. I have stopped counting how many there was in the shop.
It was booth MW and M seriepumps.
Link here
http://www.sttemtec.se/1/1.0.1.0/51/1/index.php
(04-02-2011, 04:15 AM)300D50 My guess is that the manufacturer adresses this with Bosch, and they work out a proper test plan based on the differences between the test bench system and the actual motor.