Questions involving I.P. timing. - Page 2 - PeachParts Mercedes-Benz Forum

tangofox007 · #16 07-20-2011, 09:58 PM

Quote:

Originally Posted by sethza

But it's still confusing me on why it didnt start dripping untill so late.

What was happening before the dripping started?

leathermang · #17 07-20-2011, 10:07 PM

Perhaps I am having a brain freeze.. or a heat stroke more likely... but if ( and that is a BIG IF ) everything has been done correctly leading up to this finding of the drip starting at the wrong time...
would that not indicate that you needed to rotate the IP to get it to the proper start time ?
Somebody slap me if I need that... and don't quote this post...so I can remove it ...if need be.... LOL
What concept am I missing ?

Diesel911 · #18 07-21-2011, 12:46 AM

My thoughts when I am reading this thread:

What I find odd is that in this last 12 months there has been more than a few Members with 240Ds that have had trouble timing their Fuel Injection Pumps.
More so than the owners of 300Ds or Sds.

Also I have often commented on the need to keep the pressure as even as possible with the Hand Primer (in general higher pressure = more drips; lower pressure= less drips, even pressure = the same number of drips; if the Fuel Injection Pump remains in the same position) to the extent that I have said to let someone else do the pumping while you Rotate the IP and count the drips/drops.

Since in use the IP timing is going to become more late/retarded the IP really only needs to be moved in one direction to correct the timing if your are correcting the timing on an that IP has been on a running Engine for a long time.
If 24 BTDC on the compression stroke is what you want set; set the Crank Damper and Pointer to that and nudge the top of the IP towards the Engine Block to it drips properly while someone else is doing the pumping on the Hand Primer.

The problem is simply that it is easy to rotate the Fuel Injection Pump to far (a reason why it is a good idea to scribe a line on the Pump and Block so that you can return it to the original spot if you go to far). It only needs to be nudged a bit (the Fuel Injection Hard Lines should be removed to make it easy to nudge the IP without any resistance from them).

leathermang · #19 07-21-2011, 01:00 AM

240d owners are not as smart as you five cylinder guys.... missing a 'cylinder'..
At one point we talked about trying to standardize the fuel pressure by putting it a couple of feet above the engine.... I really do not trust that any kind of repeatable constant pressure can be acquired with the hand pump....
I wonder if the slack needs to be taken up from one direction... IE, like using a table saw ripping fence... if you get it too close.. you take it back out and bring it back in with the forward edge closest to the blade line... if the IP gets too far .. does it need to come way back and hit the right spot going a certain direction ?

tangofox007 · #20 07-21-2011, 09:14 AM

...if ( and that is a BIG IF ) everything has been done correctly leading up to this finding of the drip starting at the wrong time...
would that not indicate that you needed to rotate the IP to get it to the proper start time ?

If the timing is, in fact, as retarded as believed, there will not be enough adjustment range available to get to 24* BTDC. The IP will hit the stops first, making it necessary to remove and "re-zero" the IP.

leathermang · #21 07-21-2011, 09:18 AM

Quote:

Originally Posted by tangofox007

...if ( and that is a BIG IF ) everything has been done correctly leading up to this finding of the drip starting at the wrong time...
would that not indicate that you needed to rotate the IP to get it to the proper start time ?

If the timing is, in fact, as retarded as believed, there will not be enough adjustment range available to get to 24* BTDC. The IP will hit the stops first, making it necessary to remove and "re-zero" the IP.

OK.. did you say ' nothing needs to be marked' because the setting of the ip is straight forward... thus... he needs to re zero the IP, and move the IP to set the start of delivery via the one drip per second method ?
Approx how many degrees of range does the IP have ?

tangofox007 · #22 07-21-2011, 10:09 AM

Quote:

Originally Posted by leathermang

OK.. did you say ' nothing needs to be marked' because the setting of the ip is straight forward... thus... he needs to re zero the IP, and move the IP to set the start of delivery via the one drip per second method ?

Following the "re-zero," start of delivery still needs to be fine-tuned with the drip method, etc. Same basic concept as installing a distributor. You align it visually, but you still need to use the timing light to get it right.

Quote:

Originally Posted by leathermang

Approx how many degrees of range does the IP have ?

I would estimate that it's around 25 crankshaft degrees from stop to stop. I have been unable to get even 10 degrees of advance from the factory position (IP reasonably in the middle of the adjustment range) before hitting the stops.

Also keep in mind that significant repositioning of the IP will require substantial bending of the delivery lines. (Another argument for remove and re-index.)

Stretch · #23 07-21-2011, 10:21 AM

All this messing about with drip tubes makes me wonder what on earth Mercedes did when they built these bloody things. I can't see a production line past say 1940 messing about with drip tubes - it is far too labour intensive.

Am I too far off an another tangent?

Relevance to the thread would be - set it up like they did in the factory - it should run even if the IP is worn etc

leathermang · #24 07-21-2011, 10:47 AM

Army, the drip tube method has the potential for compensating for any kinds of wear in the system... it is a ' bottom line' setting of the fuel to the position of the piston... a very reliable and trustworthy concept..
And also SIMPLE...a factor not to be underestimated... even at the risk of seeming TOO SIMPLE....LOL

Diesel911 · #25 07-21-2011, 12:11 PM

Quote:

Originally Posted by leathermang

240d owners are not as smart as you five cylinder guys.... missing a 'cylinder'..
At one point we talked about trying to standardize the fuel pressure by putting it a couple of feet above the engine.... I really do not trust that any kind of repeatable constant pressure can be acquired with the hand pump....
I wonder if the slack needs to be taken up from one direction... IE, like using a table saw ripping fence... if you get it too close.. you take it back out and bring it back in with the forward edge closest to the blade line... if the IP gets too far .. does it need to come way back and hit the right spot going a certain direction ?

When I worked in a Fuel Injection Shop we had a gravity feed setup for Flow/Drip Timing the Fuel Injection Pumps. The same setup was used on other companies Fuel Injection Pumps; where it could be used.

I have also seen a pic in one of the Paper Mercedes Manuals showing a gravity feed setup.

The Test Stand had an Electric Pump that could be used for the same purpose and I have also used the Automotive type 12 Volt Electric Fuel Pumps for timing.

As far as accuracy goes each Element in the Fuel Injection Pump is Flow/Drip Timed to the Fuel Injection Pump Camshaft (with a Degree Wheel) on most of the Inline Fuel Injection Pumps back in the 1970s.

The method I use when I timed my Mercedes IP was to nudge the pump in one direction a little and leave it there and then start pumping on the Hand Primer and then count the drips/drops while pumping. If the drips are not right I nude it again; leave it there and pump the Hand Primer again and count the drips; repeating that until I get the number of drips I want.

The Fuel Pressure Relief/Overflow valve is supposed to keep the pressure even.

Commenting on another post; Drip Timing does compensate for IP Camshaft and Roller/Pin wear (The AB Light and the Timing Pins do not do that). But, only on the #1 Element.

Diesel911 · #26 07-21-2011, 12:19 PM

Quote:

Originally Posted by Army

All this messing about with drip tubes makes me wonder what on earth Mercedes did when they built these bloody things. I can't see a production line past say 1940 messing about with drip tubes - it is far too labour intensive.

Am I too far off an another tangent?

Relevance to the thread would be - set it up like they did in the factory - it should run even if the IP is worn etc

See post #5 for the 2 types of Timing Pins.

For the one to use with my year and model you simply get the degree marks to where thay are supposed to be at 15 degrees After Top Dead Center (after the TDC on othe Compression stroke); insert the Timing/Locking Pin and rotate the IP in whatever direction is needed for the tool to pop in place and lock the IP.

After that Bolt the IP in place and you are done.

leathermang · #27 07-21-2011, 12:24 PM

Diesel911 , Thanks for that information...

leathermang · #28 07-21-2011, 12:29 PM

Quote:

Originally Posted by Diesel911

..... But, only on the #1 Element.

Isn't that the best a normal human being can hope for ?

How much variance might there be on the other ones once number one is set properly ?

And fixing that relationship would be INSIDE the IP ... correct ?

That would put it into the realm of PRO IP SHOPS it seems like...

Stretch · #29 07-21-2011, 12:59 PM

Quote:

Originally Posted by Diesel911

See post #5 for the 2 types of Timing Pins.

For the one to use with my year and model you simply get the degree marks to where thay are supposed to be at 15 degrees After Top Dead Center (after the TDC on othe Compression stroke); insert the Timing/Locking Pin and rotate the IP in whatever direction is needed for the tool to pop in place and lock the IP.

After that Bolt the IP in place and you are done.

Oh good (said the spider to the fly!) I've been told about this - a wheel lug bolt also works.

I'm planning a little experiment when I (or if I ever) get the engine back in!

sethza · #30 07-21-2011, 03:41 PM

awesome!
this is the type of discussion i was hoping for!
So I had marked the I.P with a paint marker before I messed with it, so i went ahead and put it back where it was for now. As far as how I checked for timing chain stretch, as i had mentioned before, i took of the valve cover and set the balancer at the zero mark and observed the mark the cam bearing carrier that lines up with the mark on cam gear, which happened to be directly on the money. I dont know if I mentioned this, but the engine had been rebuilt at one time... perhaps the gentleman that rebuilt it in some way did something that made timing the ip impossible... I cant get it to drip anywhere NEAR 24 degrees before top dead center. I even tried it again, after a good nights sleep, following the manual PRECISELY. I set the mark at 24 degrees btdc, with both cams on the number one cylinder in what would be the position for the compression stroke(to make it clear im on the compression stroke for #1). I pumped the hand primer, with steady even strokes(embarassing sentence) while slowly moving the pump toward the engine. the I.P. hits the stops both ways with out any dripping. If I turn the engine while pumping the primer, it will start to drip at about 10 degrees after top dead center. WIERD. heres the kicker, the manual states to have the regulator on the pump at WOT, as i mentioned. But if i take the regulator back down to idle position, i have no problem getting it to drip at the specified amount (mb manual states one drip a second) at 24 degrees, at a position that happens to almost line up on the pump with the paint marker line i made.
As i stated, the car runs very decently after puting the old fuel injectors back on, so obviously my pump is not 30 something degrees off, and i dont think my cam chain is stretched .With my valve cover off, everything i can see looks AWESOME, cam lobes look brand new everythings clean, i think the cam chain was likely not forgotten during rebuild, but the injection pump most likely wasnt messed with...but was most certainly REMOVED.

only TWO possibilities as i see it:

I am doing this wrong

The guy who rebuilt my engine put something together wrong, so that even though everything is actually working correctly, the marks will never line up properly for the purpose of timing the engine.

I have a hunch that I'm just doing something wrong, even though the instructions in the manual are pretty consice. Even though I most likely dont actually NEED to ADJUST my pump, for the sake of knowing how and for everyone out there who does need to do this we should get some more input here... I'd still like to check it just to make sure Its right on the money.

So first things first:

Is there a good thread here for checking the timing? If not, ill start with the first step: how do I make sure i'm at the right position for being at the compression stroke for #1 cylinder?

And thank you for the heads up, i didnt realize it was bad to turn the engine backwards.

Seth