need injectors calibrated - Page 3 - PeachParts Mercedes-Benz Forum

Mitch H · #31 10-28-2005, 07:31 AM

3000 psi leaves you operating between 60 & 80% of full scale, what's wrong with that?

$100 gauge not needed, $10 gauge probably useless, you need enough dial size and precision to see a difference of one bar or so. You do not need lab grade accuracy as long as you have repeatability. The pop pressures could be 10 bar off and I wouldn't care, as long as I could get them within 1-2 bar of each other.

#32 10-30-2005, 10:58 PM

Quote:

Originally Posted by Mitch H

3000 psi leaves you operating between 60 & 80% of full scale, what's wrong with that?

$100 gauge not needed, $10 gauge probably useless, you need enough dial size and precision to see a difference of one bar or so. You do not need lab grade accuracy as long as you have repeatability. The pop pressures could be 10 bar off and I wouldn't care, as long as I could get them within 1-2 bar of each other.

In the Navy, we were taught that a hydraulic pressure gauge should be capable of reading twice the normal expected pressure and should never exceed 80 percent of the gauge scale. For this application, it should be all right if you are reading pressure at 80 percent of the gauges capability since the gauge would be used so seldom I would think the technical rule could be broken. The hard part is finding a gauge with figure intervals and hash marks in the right range unless you use a laboratory grade gauge. As to the pop pressure of the injectors it all depends what is most important to you if it is a smooth ride 5 injectors at 125bar for a turbo diesel is better than 5 injectors that range from 135bar to 143bar. Perfect set in MHO would be all at 141bar
Dave S

#33 10-31-2005, 02:18 AM

The injector shop just put my injectors up at 2200PSI (or 150bar)

Seems to work good but my idle is still rough (delivery valves or precombustion chamber problems)

funola · #34 02-27-2006, 09:54 PM

Anyone else built one of these? How's it working for you? Any pics?

Does anyone have a Bosch pop tester in the NY tri-state area? I'd like to see what the spray pattern of my injectors look like.

Quote:

Originally Posted by boneheaddoctor

Credit goes out to OLD300D who sent me this a while ago.

Pop tester parts list

--------------------------------------------------------------------------------

I bought all the parts from www.McMaster.com

1 8803T51 Bottle Jack ($12.74)
1 4000K763 3000psi gauge, 3/4" NPT ($10.04)
1 5269K311 Metric fitting, 1/8" NPT to 6mm tube ($3.12)
1 50925K197 Steel T fitting, 1/4" NPT, MxFxF ($4.27)
1 4513K341 Hex bushing, 1/4" NPT to 1/8" NPT ($0.85)
1 4513K347 Hex bushing, 3/4" NPT to 1/2" NPT ($1.18)
1 4513K344 Hex bushing, 1/2" NPT to 1/4" NPT ($0.95)

The jack must be disassembled, and the pressure relief in the cylinder plugged. I tapped it, JB welded a set screw into it, then ground it flat. Remove the seal from the top nut and tap it 3/4" NPT. I JB welded the bushing into this thread as well. The gauge and 1/8" NPT bushing thread into the T, the injector line is cut and is fitted into the metric tube adapter. I also tapped and fit the bottle jack for a funnel into the reservoir to keep fluid in the cylinder, as quite a bit is pumped out as you test injectors. I used ATF and Marvel mystery oil to fill the tester.

Bajaman · #35 02-27-2006, 10:42 PM

It works like a charm. Only thing I would change is an inline filter (pressure side) but I haven't found any that would work. I know there has to be something out there to filter under high pressures. I'm thinking something along the lines of a sintered filter used in heating oil burners. Anyone know of such a thing that filters down to 5 micron or so?
bb

funola · #36 02-28-2006, 11:21 AM

Do you or anyone else have a pic? Why is the filter necessary? Are the injectors clogging during popping? How about prefiltering the test fluid?

Quote:

Originally Posted by Bajaman

It works like a charm. Only thing I would change is an inline filter (pressure side) but I haven't found any that would work. I know there has to be something out there to filter under high pressures. I'm thinking something along the lines of a sintered filter used in heating oil burners. Anyone know of such a thing that filters down to 5 micron or so?
bb

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