I have been busy playing with circuits and did some preliminary tests using an LED as the light source, which turned out to be too dim to be practical so I moved onto a Xenon timing light. Bought a cheap Actron today for a test and it is flashing! I took a video and will try to upload later.

I am using the RPM magnetic sensor by the harmonic balancer as a trigger for the testing. Once I have the proof of concept completed, I will install an rpm sensor in the IP timing port for the final product.

I want to establish accuracy of the timing light and whether there is any propagation delay and have a few questions about the timing marks.

The red arrow is pointing to the magnetic sensor.

yellow line is pointing to the trigger tooth (with green paint on top of tooth to make it easier to see). Is the tooth TDC at zero degrees?

Is blue line pointing to 10 degrees ATDC

Is green line pointing to 20 degrees ATDC?

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Not to be nit picky but isn't it Xenon as in the noble gas? Isn't Zenon a Disney movie?

My 617 days are long ago but IIRC the crank pulley doesn't indicate TDC/0|T when the trigger tooth is centered in the sensor holder. In any case, the 0|T mark indicates TDC and the trigger tooth isn't close to the sensor holder. The blue line is at 10*ATDC, the green line looks like it's at 25* ATDC. If the green circle is centered on the yellow line, that would be 5* BTDC. I can't tell from this angle but I'm guessing there's more than 5* separation between the visual indicator and sensor holder.

Sixto
87 300D

The 617.95 FSM 03.8-345/2:

"The pin in vibration damper should be accurately under the TDC transmitter at crankshaft position 20 degrees after TDC."

Your are right about spelling of Xenon. I agree with you that the tooth and sensor has no relationship to IP timing. I am using it as proof of concept. If there is no propagation delay, the tooth should be directly under the magnetic sensor while the Zenon light is strobbing.

Below is a video of the timing light . The tooth is not visible so it somewhere under the magnetic sensor.



CLICK TO PLAY!





The green paint mark to the left of the pointer is at 25 degrees, which you can see in this pic (pointed to by green line)

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Pretty sure the 20 degree mark on the balancer is the line between the 2 and the 0, just like the 10 degree mark is between the 1 and the 0, so the green paint looks to be at 25 degrees, no?

You are right! Thanks for helping me to see.

Now that I look closer at the pic, the zero degree mark is between "0" and "T" where the T mark needs more cleaning to be legible.

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

If you wire brush the area around the marks good and clean out the marks themselves some, you can them apply some paint over them and then wipe it off leaving some paint down in the stamped marks, makes it a whole lot easier to see what your looking at. White or a bright florescent paint works great.

On a 603 engine the timing marks are moulded into the rubber of the balancer and are raised instead of indented, then I cover the whole area with acrylic paint marker paint like the boneyards use to mark parts and then using a razor blade scrape the paint off the raised rubber numbers to get a black mark against a colored background effect.

Yes I need to clean it better and make the marks more visible with paint. Before I used a wire brush duct taped to a long stick to clean those marks, they were totally illegible. I don't think I can reach in there without taking off the upper rad hose. I don't really feel like doing that!

Thanks for pointing out FSM 03-345 checking and correcting adjustment of TDC transmitter, which states:

"The pin in vibration damper should be accurately under TDC transmitter at crankshaft position 20 degrees after TDC."

Looking at the video, the metal pointer is pointing at 20 degrees after TDC. That means the vibration damper pin is accurately positioned under the TDC transmitter, which means my timing light circuit in combination with the Xenon timing light has no propagation delay and is accurate! Cool! Now I can move onto the next phase, to come up with a magnetic sensor for the IP timing port.

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Do you have more direct access to cleaning the timing marks from below the engine?

Sixto
87 300D

Yeah, and if you have the engine running you can just lay the wire brush on it and it's cleaned up in a minute or so. I use a plumber's round pipe fitting wire brush that has a twisted metal handle because you can bend that to get at things, also great for cleaning splined prechamber rings befor putting the tool to them.

There should prove to be no practical relevant system delay electronically at the low idle speed whatsoever I suspect for all practical purposes. I am not going to get seriously involved in this but you are shooting for the tang in the injection pump in relation to the harmonic balancer comparison dynamically I suspect?

What you may also be doing is getting someone out there or yourself to now figure a way to enhance these engines further with some electronic manipulation. Or paving a possible path of some sort perhaps.

Maybe a variable turbo at some point is not an impossibility. Could provide functional practical boost from idle speed upward perhaps. I suspect it is not impossible.

Doing it from underneath with a brush with engine idling is a great idea! Just need to be careful and not knock the trigger tooth off. I'll look for a wire brush with bristles that are longer than the tooth to lessen the chance of that happening.

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Yes, my final product is to trigger off the tang in the injection pump. Triggering off the tooth on the harmonic balancer is just a stepping stone /proof of concept. Since the IP tang timing light is only applicable to certain year IP's, I am also working on a timing light that triggers off of pulses on the injection pump hard lines. If successful, it should work universally on all injection pumps. It would then be interesting to compare results and differences of the 2.

I probably will not be getting into the hardcore stuff like adding a VNT, just tuning mine to get better efficiency/economy. If my timing light project ends up being successful, I can offer it in the rental program.

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked