Dynamic diesel timing (renamed thread)

[Brian Carlton]

Originally Posted by Stretch

Sorry I forget where I am sometimes...

Loose translation

Heading for second column from left is Motor RPM

Heading for third column from left is Engine oil temperature in degrees C

Heading for the column on the right shows the degrees of crank rotation delivery should happen BEFORE TDC

prüfwert is the test value

einstellwert is the setting value

I believe we discussed, via PM, that I produced correlation between A-B timing lights and dynamic timing on the 617.

The 617 is precisely timed at 24 BTDC with the A-B lights, the dynamic timing with the pulse adaptor shows 15 BTDC at idle.

It may be possible that there is a bit of advance occurring at 1000 rpm (the value in the table) and the spec of 19 BTDC is correct. However, holding exactly 1000 rpm for the entire time necessary to make the adjustment is a PITA and performing the adjustment at idle using the 15 BTDC spec would be a whole lot easier.

Would be interesting to confirm the advance from 15 BTDC to 19 BTDC between 650 and 1000 rpm.

[Stretch]

Originally Posted by Brian Carlton

I believe we discussed, via PM, that I produced correlation between A-B timing lights and dynamic timing on the 617.

Contrary to the presented table above, when the 617 is precisely timed at 24 BTDC with the A-B lights, the dynamic timing with the pulse adaptor shows 15 BTDC at idle.

I'm quite certain that 20 BTDC is incorrect.

Hi Brian,

I was getting round to sending you a PM about this. Sorry I didn't do this sooner - I do value your input.

As I said I was looking for official documentation - I'm glad to have found it. I do find it interesting that Mercedes say about 19 degrees before TDC and you've observed 15 degrees before TDC.

(Today) I can think of a two reasons why this might be

1) The turbo OM617 (the data for which I have not found listed by Mercedes) has its injectors set at a different pressure from the non turbo ones - the turbo engine might be designed to deliver fuel later than the non turbo for some air fuel ratio reasons that I don't fully understand yet

2) The equipment used to measure the point of delivery might be working in a way that is influenced by the ignition of fuel in the cylinder rather than the point of delivery

For example if you were to look at the output of the transducer mounted to an injector line it MIGHT look a bit like this =>



(please excuse my wobbly mouse hand!)

Now this is pure conjecture - the point I'm trying to make is that the electronics in a box might be tuned to pick out the biggest spike within a certain period of time and it might be picking out the wrong one - it is always nice to see an output as a function of time of a transducer - this doesn't happen with these systems...

[ichris93]

Originally Posted by Stretch

Would it help if I draw out an English translation?

Here you go

[Diesel911]

Originally Posted by layback40

Care to translate.
If its dynamic timing data then all is good.
A smart guy like you should be able to put an inductive pick up on the side of an injector & get a signal when it pops. Or find a good #1 injector out of a VM TD. they used them in lots of cars over your way.

For Language Translation
http://translate.google.com/


.

[Stretch]

Originally Posted by ichris93

Here you go

Thank you very much - lets make that big!

[Brian Carlton]

Originally Posted by Stretch

Hi Brian,

I was getting round to sending you a PM about this. Sorry I didn't do this sooner - I do value your input.

As I said I was looking for official documentation - I'm glad to have found it. I do find it interesting that Mercedes say about 19 degrees before TDC and you've observed 15 degrees before TDC.

(Today) I can think of a two reasons why this might be

1) The turbo OM617 (the data for which I have not found listed by Mercedes) has its injectors set at a different pressure from the non turbo ones - the turbo engine might be designed to deliver fuel later than the non turbo for some air fuel ratio reasons that I don't fully understand yet

2) The equipment used to measure the point of delivery might be working in a way that is influenced by the ignition of fuel in the cylinder rather than the point of delivery

For example if you were to look at the output of the transducer mounted to an injector line it MIGHT look a bit like this =>



(please excuse my wobbly mouse hand!)

Now this is pure conjecture - the point I'm trying to make is that the electronics in a box might be tuned to pick out the biggest spike within a certain period of time and it might be picking out the wrong one - it is always nice to see an output as a function of time of a transducer - this doesn't happen with these systems...

See my amended post #31.

I realized that the spec is at 1000 rpm and my tests were all done at 650 rpm. That is the most likely reason for the discrepancy of four degrees.

[Stretch]

Originally Posted by Brian Carlton

See my amended post #31.

I realized that the spec is at 1000 rpm and my tests were all done at 650 rpm. That is the most likely reason for the discrepancy of four degrees.

With the non turbo you have the fast idle knob which probably helps with the 1000 rpm vs idle problem.

I'm not sure that the discrepancy of 4 degrees can be explained by a difference in 350 rpm though. The timing device alters a maximum of 7.5 degrees (was 6 degrees for the pre-1980 non turbo engines). I don't think the timing device is meant to do anything below 2000 (may be 1800) rpm - so that's about 1 degree for about 400 rpm ( {5000 rpm - 2000 rpm} / 7.5 degrees )

[layback40]

Stretch,
The injector I am talking about is a Bosch
From my notes~


the no.1 injector. check connector with a multi meter, i think under 80 ohms is good.

Injector #1 0986430248 or 0432217249 maybe 0430211091 or 0432217249
IDZ1023 equivalent to 15 06 2022F, 15 06 2026F There are 2 different blow pressures ~ 150 & 165 bar

KCA30S82 boschowski number is 0432 217 246

0432217303

GERMANY 060 KCA 30 S 82 369 150

You can probably google some pics. It detects the pintle moving. As I posted previously, its inductive so the combustion shock shouldnt effect it.
I suspect if you were to grind the side off an injector so there is less metal between the sensor & the pintle. A RF style sensor like used to be used in radios etc may work.

[Stretch]

Originally Posted by layback40

Stretch,
The injector I am talking about is a Bosch
From my notes~


the no.1 injector. check connector with a multi meter, i think under 80 ohms is good.

Injector #1 0986430248 or 0432217249 maybe 0430211091 or 0432217249
IDZ1023 equivalent to 15 06 2022F, 15 06 2026F There are 2 different blow pressures ~ 150 & 165 bar

KCA30S82 boschowski number is 0432 217 246

0432217303

GERMANY 060 KCA 30 S 82 369 150

You can probably google some pics. It detects the pintle moving. As I posted previously, its inductive so the combustion shock shouldnt effect it.
I suspect if you were to grind the side off an injector so there is less metal between the sensor & the pintle. A RF style sensor like used to be used in radios etc may work.

Thanks I'll look into that. Some other company was making pressure sensing glow plugs - I can't remember who that was now though...

...but they might be useful too (though you'd definitely get an output that had both delivery and ignition then)

[layback40]

Originally Posted by Stretch

Thanks I'll look into that. Some other company was making pressure sensing glow plugs - I can't remember who that was now though...

...but they might be useful too (though you'd definitely get an output that had both delivery and ignition then)

Having the 2 signals you could probably calculate a type of centane number.

[Stretch]

Originally Posted by layback40

Having the 2 signals you could probably calculate a type of centane number.

You most certainly could get a type of real world working cetane number.

It would probably be quite a good indication for low engine rpms as the delay in transmission time of ignition from the cylinder to pre-chamber (in an OM61X engine) would probably be (at a guess) small in comparison with the time between the delivery pulse and the ignition pulse (as pictured in my wildly imaginative sketch above!). At higher engine speeds your transmission time will get closer to the distance in time between the pulses - also you're gonna need to pretty nice transducers...

I'm not sure if it would provide a realistic relationship with the cetane number on the can (so to speak) as the OM617 isn't a standardised test engine


(Further reading for those who are interested => Cetane number - Wikipedia, the free encyclopedia)

[1project2many]

The tool I referred to earlier is for quickly confirming activation of electronic fuel injectors. Waekon 76462 EFI Quick Probe (Orange Probe) It might be too sensitive to use with a diesel although I'm sure a desperate and / or creative guy could devise a method to reduce sound transmission to the unit.

I've used a Snap-On MT257 with success on GM 6.2/6.5 liter diesels when I worked at a Chevrolet dealership. This tool is another type of pulse adapter for a timing light. I was in truck country back then and there were plenty of these engines around so I could come up with a good baseline for setting / checking timing. Occasionally a used one can be found for sale on the internet.

If the engine is set up with correct timing using the mechanical setting then checking with a light for maintenance only requires an initial check and subsequent re-checks as desired. The only need to determine the exact difference between mechanical specification and the measurement by the light is for 1) motorsports and racing, 2) comparison with others, or 3) because you enjoy hunting down that type of minutia. Otherwise, the initial measurements will serve, IME, as a perfect tool for future checks. Engine temperature, pop pressure variations, and injection pump condition all affect the timing result obtained so it seems as though "within a degree or two" became the acceptable standard for using the inductive light with adapter. IMO you're better served looking for fuel with consistent quality.

[Brian Carlton]

Originally Posted by Stretch

With the non turbo you have the fast idle knob which probably helps with the 1000 rpm vs idle problem.

I'm not sure that the discrepancy of 4 degrees can be explained by a difference in 350 rpm though. The timing device alters a maximum of 7.5 degrees (was 6 degrees for the pre-1980 non turbo engines). I don't think the timing device is meant to do anything below 2000 (may be 1800) rpm - so that's about 1 degree for about 400 rpm ( {5000 rpm - 2000 rpm} / 7.5 degrees )

Well, I took a shot at the reason for the discrepancy.

Without the timing device as a factor, it's a significant difference between 15 and 19 degrees.

I now wonder if the specific equipment utilized, and/or the procedure utilized will result in this difference..............not a good situation.

[Stretch]

Originally Posted by Brian Carlton

Well, I took a shot at the reason for the discrepancy.

Without the timing device as a factor, it's a significant difference between 15 and 19 degrees.

I now wonder if the specific equipment utilized, and/or the procedure utilized will result in this difference..............not a good situation.

Oh you strike me as a reliable chap Brian! When I actually get some experience in this matter rather than dreamy theory I guess I'll have a better idea about it all.

[funola]

Hey Stretch, any progress getting your timing light to work on a diesel? Here's another piezo adapter (by Ferret around $200).

https://www.youtube.com/watch?v=4GtFvIhDXzk&feature=youtube_gdata_player