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1983 300 CD
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22 Posts
Discussion Starter #1
What is the most you have seen the timing off by? I have been using this testing method (link below) and mine is coming up consistently around TDC. According to the reference marks (chisel crease)on IP and block, timing it has not ever been moved. Checked chain stretch and timing is about 1 degree after TDC. Starting to wonder if the problem may be me? If it is common to off by this much I will go ahead and adjust it.


Injection Pump Timing Adjustment for 617 Engines


I have read about the "drip Method", but that sounds like too much room for error.

Car feels down on power and first 1/4 of accelerator pedal feels very sluggish.

Thanks in advance!


1983 300 CD
 

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2001 Volvo V40
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2,954 Posts
The drip method is more accurate than this method.

It should well up fuel around 24 degrees before TDC in the compression stroke of cylinder one, not at TDC as you describe. The IP should be at its mark and the engine at 24 degrees before TDC.

The worst I've seen in 19 degrees before TDC.
 

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1984 300D
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5,096 Posts
When I first got my Car the low end speed of my Car was so slow it was scary; yet once it finally got up to speed it was fine.
The problem was due to; too much slop in my Throttle Linkage.

Have someone step slowly on the Accelerator Pedal for you while you watch the Linkage to see if the Linkage is moving but the Throttle Lever on the Fuel Injection Pump is not moving at the same time. If so your Linkage needs adjustment.

In my case it was caused by the linkage being out of adjustment but it can also because by the Bell Crank on the fire Wall has a bad plastic Bushing or the Rubber part is failing.
 

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1984 300D
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5,096 Posts
The Drip Timing Method has stood the test of time.
Besides Bosch Fuel Injection Pumps nearly all of the other inline type Fuel Injection Pumps are Drip Timed (also called Flow Timing).

During the rebuilding of most inline Fuel Injection Pump each one of the Elements on the Fuel Injection Pump is Drip Timed to specific Degrees of Fuel Injection Pump Camshaft rotation.
This is done with a Degree wheel attached to the Fuel Injection Pump Drive end or on a test stand that has a Degree Wheel on the Test Stand Drive.
The Fuel Supply is pressurized by an Electric Fuel Pump (on the Test Stand) or a Gravity Feed setup (when doing it on a Bench)

The Fuel Injection Pump Camshaft is rotated to the proper degree mark and the amount of drips observed.

If the amount of drips is not correct each Element is adjusted for Begin of Injection at their Tappets some what like doing a Valve Adjustment or they have different thicknesses of Shims/Plates that you exchange.

A few companies do the same with the use of a Depth Micrometer or Dial Indicator set up. CAT is one of them.
 

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1984 300D
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5,096 Posts
The thing that is not covered well concerning Drip Timing is that you need to keep the Fuel supply Pressure fairly constant when you are counting the drips.

Because, you are going to get more drips at a higher Fuel Supply Pressure than you will at a lower Fuel Supply pressure.

I think the easiest way to do this is have someone pump on the Hand Primer for you while you concentrate on rotating the Fuel Injection Pump and counting the drips.
After you have done the job a few times you will be able to do it yourself.
 

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1983 300 CD
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22 Posts
Discussion Starter #6
I used the "well up" (link above) method because I didn't have the small pipe required for the flow/drip method. "Well up" method says leave the delivery valve in and the flow/drip method said to remove the delivery valve.

In my first post I got confused and did not have the delivery valve in. Once I put the delivery valve back in I was getting "well up" consistently at 12 degrees before TDC. I adjusted IP using "well up" method to 24 degrees before TDC and adjusted the Throttle Linkage.

Took her for a test drive and feels a lot better! I will re-check the timing again using Flow/drip method when I get the small pipe needed for the test.

Thanks again guys for all of your help!
 
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