How to Set IP Timing via the Drip Tube Method - Pictorial - Page 3 - PeachParts Mercedes-Benz Forum

dannym · #31 11-10-2008, 11:38 AM

You don't really need a drip tube.
What your looking for is the point where the piston rises in the bore and starts the high pressure fuel delivery to the injector. The transition from full flow to dripping happens very quickly.
Personally I just look down into the bore and look for the point where the fuel just starts to rise up (Start of Delivery).

Another way to set timing is by using the Factory Timing Tool, part #601 589 05 21 00 .
You set the timing at 15 degrees ATDC. Then you remove the bolt from the side of the IP and insert the tool. You move the pump back and forth until it locks in. Then you bolt down the IP in place. Perfect timing every time!

Danny

#32 11-10-2008, 11:42 AM

Quote:

Originally Posted by dannym

You don't really need a drip tube.
What your looking for is the point where the piston rises in the bore and starts the high pressure fuel delivery to the injector. The transition from full flow to dripping happens very quickly.
Personally I just look down into the bore and look for the point where the fuel just starts to rise up (Start of Delivery).

The bubble method, its inaccurate and shouldn't be used by anyone.

A drip tube is only $15, or free if you have an extra injector tube laying around to cut.

leathermang · #33 11-10-2008, 11:53 AM

Quote:

Originally Posted by jt20

I wanted to add that when you are adjusting the pump, you want to be Decreasing the fuel flow only.

Ok... just to keep new people's concepts in line with the physics... the procedure shown by Scott does not increase or decrease the flow of fuel to the engine. What we are talking about here is a method of setting WHEN the flow hits the bore of the engine.

Adjusting the actual fuel flow is done on the pump AND Should be left to really experienced people...

I am totally with Forcedinduction... the ' well up' method is not prescribed by the Mercedes Shop Manual but what Scott shows IS... trust the guys that made the car and have multimillion dollar R and D departments..., wrote the manual, and more importantly reputations to protect.

Stevo · #34 11-10-2008, 12:08 PM

I believe, as a general rule, if you bump the timing a 'skosh" advanced with an older 617/6 its going to run better as that "skosh' compensates for a chain thats worn some.

,

Stevo · #35 11-10-2008, 10:57 PM

Quote:

Originally Posted by ForcedInduction

The bubble method, its inaccurate and shouldn't be used by anyone.

And you are sure of this statement because....you have actually tried it??

#36 11-10-2008, 10:59 PM

Quote:

Originally Posted by Stevo

And you are sure of this statement because....

...I know better than to waste my time on inaccurate shotgun methods dreamt up by people too lazy to do things correctly or spend a few dollars on the proper tool(s).

How hard is it to take a spare injection line and use a hacksaw to make this:

Or, you could spend the $20 and buy that tool directly.

http://cgi.ebay.com/ebaymotors/Mercedes-Diesel-Fuel-Timing-Engine-Parts-Repair-Tool_W0QQcmdZViewItemQQcategoryZ35625QQihZ002QQitemZ120318124154

jt20 · #37 11-10-2008, 11:03 PM

for that matter... why can't you use your full length line?

Stevo · #38 11-10-2008, 11:24 PM

[QUOTE=ForcedInduction;2017828]...I know better than to waste my time on inaccurate shotgun methods

Ah, thats what I thought, you haven't tried it

turbobenz · #39 11-10-2008, 11:29 PM

Quote:

Originally Posted by jt20

for that matter... why can't you use your full length line?

the point is that the fuel gets to the high spot in bent line so that when any more is added, it spills over (like a gas trap in a toilet) giveing you an accurate measurement. A full injector line is to oddly shaped and long.

#40 11-10-2008, 11:35 PM

Quote:

Originally Posted by Stevo

Ah, thats what I thought, you haven't tried it

I haven't shot myself in the foot to see if it makes me bleed, do I need to try it so I know for sure what happens?

Dude, some things simply don't NEED to be tried because there is already a CORRECT procedure to do it. Who are you going to trust; the service manual written by Mercedes (you know, the people who spent a few million dollars designing these cars and engines), or a "frugal" shade-tree internet mechanic looking for shortcuts because he doesn't have the proper tools to do the job right?

jt20 · #41 11-10-2008, 11:49 PM

Quote:

Originally Posted by turbobenz

the point is that the fuel gets to the high spot in bent line so that when any more is added, it spills over (like a gas trap in a toilet) giveing you an accurate measurement. A full injector line is to oddly shaped and long.

I don't buy it. AN injector line has that shape near the injector.

Irregular shapes mean nothing to fluids.

length means nothing to pressure either. (for this distance)

The only thing the drip tube has going for it is a smaller inside diameter and a sharp drip edge... that PERHAPS, may create a smaller droplet than a tube.

Diesel911 · #42 11-11-2008, 12:20 AM

I think that before you re-time your IP you should have some idea what your Timing Chain Stretch is before you time the IP.
Example: I have 2 degrees of Timing Chain Stretch on my car (= 2 degrees retarded/late Camshaft and IP timing if the PO has not changed it).
So, if I time my IP at 24 degrees I will still be have 2 degrees of late/retarded IP timing.

In the Service Manual I believe you keep the IP bolted down and rotate the engine until you get "begin of injection" (via the drip method) and then look at the degrees and check to see how far off your begin injection is.
Afterwhich you loosen the IP and adjust (via the drip method) it to the degrees you want it to be set at.

whunter · #43 11-11-2008, 01:14 AM

Quote:

Originally Posted by ForcedInduction

...I know better than to waste my time on inaccurate shotgun methods

Quote:

Originally Posted by Stevo

Ah, thats what I thought, you haven't tried it

I have tried it, the bubble method is slightly better than doing nothing.

* The drip tube method is better.

** An electronic timing light is the best.

Have a great day.

#44 11-11-2008, 01:19 AM

Quote:

Originally Posted by whunter

I have tried it, the bubble method is slightly better than doing nothing.

Right, but with that method you might as well just loosen the mounting bolts and nudge it a MM towards the block. Same results and accuracy.

whunter · #45 11-11-2008, 01:59 AM

Quote:

Originally Posted by jt20

I don't buy it. AN injector line has that shape near the injector.

Irregular shapes mean nothing to fluids.
length means nothing to pressure either. (for this distance)

The only thing the drip tube has going for it is a smaller inside diameter and a sharp drip edge... that PERHAPS, may create a smaller droplet than a tube.

"turbobenz" is correct as far as he goes.
The drip tube is as short as possible (for the OEM) to accommodate a machine operation U bender and REDUCE the cranking needed to fill the tube for this operation.
Drip timing should be done on a flat/level parking area for best accuracy.
Diesel fuel gets to the high spot in the bent line, then when more is added, it spills over, the overflow runs down to the V-point, focusing the flow, and giving you a reasonably accurate drip/time measurement.

A full length injector line is oddly shaped and very long.

Does anyone recall injector pulse spray volume, I seem to recall it as 0.00X CC per cycle.