M400 Ignition Box used with Coils w/ Internal Igniters

[tkarttrev]

Thanks for the add, my first post.

I am converting a 1987 Mercedes 190E 2.3 Cosworth from Bosch CIS to Motec M400. The harness I got is from an asphalt drag snowmobile It has some oddball leads (ice box blower fan) but also has the necessary ones to run this 30 year old Benz mill. It is well put together and has good plugs and labels on the leads.

The sled ran a NLR Smart Ignition box and four Dynatek 2-wire coils on plug. I plan to run newer coils that have built in igniters. A common coil used in this application is Toyota 1nz DENSO part number 673-1306 which is a 4 wire coil with built in igniters. Do I need the ignition box or should I be running the coils straight from the M400?

Thank you for your advice, I am sure I will have more questions going forward. This seems to be a friendly and helpful forum.

[Stephen Dean]

Hi,

If the coils have built in igniters, then you do not need the external igniter box as the M400 can run 4 coils sequentially. If you do not have enough spare Ignition Outputs, then I would recommend using a MoTeC IEX instead.

[tkarttrev]

Thanks Stephen.

[tkarttrev]

Follow up a little off topic, but I would like to pull the cam sync from the existing distributor which has no existing sensors. With the right Hall sensor, coming in from the side, do you believe the sensor will be able to identify the keyway in the picture as the sync trigger assuming I set it up in the software? I will fabricate a cover that would hold the sensor as I will not be using the distributor cap.


Thank you. Trevor

M400 Project on a 1987 Mercedes 190 2.3-16.

[Stephen Dean]

Hi Trevor,

What material is that cup made from? It could possibly work, but it is likely that the sensor will also pickup on the depression before the keyway. It may actually be a better option to use the depression as the trigger than the keyway.

[Sean]

Don't waste your time trying to trigger off the notch. Make a trigger wheel with one lug (or notch) that presses on the shaft and is much bigger diameter. In my opinion it won't work well , if at all, trying to trigger off that notch. Eyeballing the size of the notch, seems like the width of the notch will be something like 144 degrees of crankshaft rotation.
The depression is a hollow in the distributor body casting I believe?

[tkarttrev]

Thank you Sean and Stephen. I appreciate your comment. I agree there are better solutions. I will post a picture tomorrow of an alternative using a few parts I have on the shelf.

[tkarttrev]

I still like placing the cam sync in the distributor, so I mocked this up using a stock cap for simplicity. I used a magnetic sensor, magnet tapped into a set-screw collar. I will machine an aluminum cover with flats to secure the sensor.

What considerations come to mind. Thanks

[tkarttrev]

Is that attachment as giant as it looks?

[Sean]

It's colossal! If you're using a mag sensor the trigger wheel can be plain steel with a single lug. I have never seen a magnet triggering a mag sensor in a ref or sync application with Motec, though it's common enough with MSD.

Make the outside diameter of the trigger lug as large a diameter as you can for more accuracy. Allow for a way to adjust the air gap from sensor to trigger wheel. Can the distributor can be rotated in the normal manner as you would when adjusting timing, so as to be able to move the sync pulse to the optimal position. If not, some adjustment on the sensor mount would be optimal. This is so as to be able to move the sync pulse to a nice position in between the ref pulses. The hundred series ecu don't like the 2 on top of each other I believe you'll find.