timing with pulse light
 

Hi,

can anyone explain me why the readings (settings) are different to those of i.e. the droplet method?
Are any settings known how to check the advancing device with the pulse light (AVL 875)?

And believe it or not she’s on the road now!! My 82 SD was sitting for nearly 4 years until I got the main work done and the license plates fitting into the front bumper.

Now after the first thousand km (still running) I put my hands on fine tuning.

Thanks from

Tom (WestCoastGermany)

I beleive the Factory Service Manual reccomends using the drip method, that is what I would use.

How did you get a 300SD in Germany? Those were US only cars.

A good friend imported the SD personally in 2002. There are very few of them on German roads.

I used the drip method in the past but now I am playing with individual cylinder timing.
In combination with thin injector lines of the 124 the ip timing can be changed with the lines attached and engine running.

Tom

If you are setting with the pulse light, use a value of 14°BTDC as the spec.

Brian,

What is the reason for this difference?
The pulse in the line is the pressure peak?
Should I see different readings when placing the clamp near to the IP compared to near to the injector?

Tom

The drip method is measuring start of delivery (the start of fuel being compressed). When you use a piezoelectric timing light you are measuring start of injection (pressure has built up in the lines enough and the injector actually starts injecting fuel). I'm not 100% that its start of injection with the timing light (might be end of injection or something), but start of injection is the most likely IMHO.

I've never seen anything. If you find something though PLEASE share!! :D

Maybe. Everyone says liquids aren't compressible, but I was reading something from Bosch (forget where exactly) that says that at the pressures and speeds the IP puts on the fuel there is actually a compression wave that travels through the line. I don't know if it is possible to measure that with the timing equipment, but I would think its possible.

news from Bosch
 

using the AVL 21 +-1.5 deg BTDC @1000 rpm is spec. (with clamp near injector and lamp onto balancer). (for SUN and some others it is 18 deg)
For my AVL I also got a cable connection to the diagnostic socket instead of the lamp. Using this I can see the approx. 25 deg BTDC on the display of the AVL 875.
With the lamp I saw the 21 deg.

There are no specs for the advancing device.
If there is approx. 10 deg advancing @2000 rpm then the device is o.k.
The Bosch guy said it is only black or white, nothing in between.
No advancing means broken (noisy) or blocked movement by a wrong screw, but no wear or weak springs.

Tom

With the wet static method, spec is 24° BTDC. (This is for OM61x engines, not OM60x.)
With the dry static method, spec is 14° ATDC. (Actually, 15° in older manuals.)
With dry dynamic FACTORY methods, it's still 14° ATDC, since this still plugs into the hole in the side of the pump, NOT using a piezo on the metal fuel line.

If you're using some tool that senses via piezo on the fuel lines, ideally you would set it with a factory method first, then test with the piezo and figure out what the correlation is. Numbers you get from anywhere else could be erroneous.

There is a spec to check the timing device, the FSM says it with the dynamic RIV it should be +3° to +5° at 5100rpm.

:scholar:

Dave,
thanks for clarifying.
What is FMS (timing device spec)?
The other numbers came from Bosch, Diesel injection shop.

Sorry - I forget sometimes that not everyone is familiar with acronyms, lol. FSM = Factory Service Manual. You can get it on CD-ROM, and some nice person made it available online here (W124 only, but that includes the 602/603 for the SDL as well).

:wacko:

Those values are incorrect.

I can assure you that 15ATDC with the RIV tool is precisely 14BTDC when you use the pulse generator sensor on the #1 fuel line.

Those numbers sound more reasonable. Remember that the number for the pulse generator (14° BTDC) will match NOTHING in any of the factory manuals, because you're using a totally different reference point.


:cool:

Dave, for reference, we did a back to back test........checked timing with the RIV.......spot on 15°ATDC.........and then checked the pulse unit........right at 13.8°BTDC.

I'm confident in this data.

Guys 2 questions:, how much is the pulse light?

Also, it seems that the IP for the 606.910 has splined "outputs" ( sorry nomenclature escapes me). I ASSUME these splines are for "microtimng" each cylinder. If so, how does one do that? It seems your pulse method might be the only way, and then, at exactly which crank position?

I will learn how to tune this enigne! THNX!