Scientific Diesel Purge Test, your Input wanted - Page 2 - PeachParts Mercedes-Benz Forum

KarTek · #16 12-28-2008, 08:41 AM

I just ordered some Diesel Purge. I have a pretty badly nailing #5 injector. When I finish my pop tester in a couple weeks, I'll post some before and after results.

strelnik · #17 12-28-2008, 08:58 AM

Quote:

Originally Posted by KarTek

I just ordered some Diesel Purge. I have a pretty badly nailing #5 injector. When I finish my pop tester in a couple weeks, I'll post some before and after results.

Evan,
I saw that your "fleet" includes and Unimog. Is it gas or diesel? I am looking for diesel Unimog parts
Thanks,
s

KarTek · #18 12-28-2008, 09:26 AM

Strelnik,

Are you looking for OM352 parts for 406/416 models?

Try here:

http://www.expeditionimports.zoovy.com/c=lHqNXm3Yv6mEfqakG8iY05OGS/category/unimog_404_parts.bdiesel_parts/

They're mostly for 404 models but it's a start. My 404 is a gasser - M180.

strelnik · #19 12-28-2008, 11:06 AM

Actually I'm looking for OM636 parts.

Yeah, it kinda dates things but I need them for my 1950 170

bgkast · #20 01-15-2009, 03:02 AM

OK, the results are in. I first did a baseline test using 50 pumps (about 10 oz) of Diesel. The spray pattern slightly improved in this test. I then drained the pop tester and filled it with Lubro-Molly Diesel purge and repeated the test with a different injector. The spray pattern actually got worse, perhaps because the DP dislodged a chunk of crud in the injector. Because of this skewed result I repeated the DP test with another new injector. The diesel purge improved the spray pattern in the second DP test.

Pictures as follows:

1 - Spray pattern before test with diesel
2 - Spray pattern after test with diesel. The spray pattern has widened to a more normal size
3 - Spray pattern before Diesel Purge test 1
4 - Spray pattern after Diesel Purge test 1. Yes that is only one spray. Something was plugging the nozzle causing a V shaped spray

bgkast · #21 01-15-2009, 03:05 AM

Pictures continued:

5 - Spray Patten before diesel purge test 2. The injector was spraying a stream which caused the irregular spay pattern shape.
6 - Spray pattern after diesel purge test 2. Again the spray pattern has widened to a more normal size

My conclusion: Diesel purge did not show any better results than plain diesel.

whunter · #22 01-15-2009, 12:46 PM

Quote:

Originally Posted by bgkast

Pictures continued:

5 - Spray Patten before diesel purge test 2. The injector was spraying a stream which caused the irregular spay pattern shape.
6 - Spray pattern after diesel purge test 2. Again the spray pattern has widened to a more normal size

My conclusion: Diesel purge did not show any better results than plain diesel.

Interesting spray pattern.
Injector cleaning chemical bench testing is possible, I have worked with several OE test benches that can, they are in the $400K - $500K range, and require weeks of training to operate.

Not a valid scientific test of DieselPurge:
* Engine temperature is needed for correct chemical reaction, best results are always at 80C = warmed to operating temperature before using dieselpurge
* Roughly 1/5 of the can must be cycled through each injector
* Time/flow recycling return fuel through injection system is important

hey_allen · #23 01-15-2009, 02:00 PM

While I currently lack a pop tester to play with, I am tempted to build one just to test the question of what affect ultrasonic cleaning might have.

I would think it a much more effective way to clean our injectors, especially if they're already off of the car.

I have used DP, and it seemed to have a positive effect, but I wonder just how much of that was in the injectors, and how much was pre-chamber cleaning.

KarTek · #24 01-15-2009, 02:09 PM

When I get my pop tester done here in a couple weeks, I'll do the same test on my 606 set.

Bajaman · #25 01-15-2009, 03:54 PM

The best test would be to assess the spray pattern before doing a DP in the car then after. Then you know how it performs.

KarTek · #26 01-15-2009, 04:43 PM

That's what I plan on doing...

Pull, pop, spray, observe, take pictures, re-install, purge, pull pop spray, observe, take more pictures...

Yeah, I think that's it...

winmutt · #27 01-15-2009, 05:19 PM

There is no scientific way to do this without identically clogged injectors. Or atleast a much larger set of tests.

KarTek · #28 02-20-2009, 11:23 AM

Just bringing this back to the top. I should be able to accomplish this test this weekend provided I have all the right tools and my new, untested pop-tester works...

milner351 · #29 02-20-2009, 11:40 AM

Man were my injectors really messed up!

Thanks for the rebuild Bryan - I can't wait to get this darned thing running again....

I'm starting to devise glowplug removal methods in my sleep! argh....

KarTek · #30 02-23-2009, 10:24 AM

Well, I started this yesterday and I got through the pre-test and purge. Next, I'll remove and re-pop.

Results are less than encouraging.

The pre-test spray pattern on the worst offending injector ranged from a somewhat normal "tilted" plume to 3 simultaneous streams. Engine knocked badly in #5 both before and after the purge.

I hooked the bottle up and ran it up the road with a couple full throttle blasts. Note: one can of DP will run you car about 2 miles... I ran it out of fuel on a curve of the road with no where to pull off!

I jumped out and had the original fuel line hooked back up in about 2 minutes.

Here's a video I shot of the initial pop test. Sorry for the poor quality...

http://www.youtube.com/watch?v=LHiAnUTfgmk

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