OM606 into W108 280SE

TA 0301

63

05-07-2014, 03:50 PM #6

Edit: Don't follow the instructions in this post, it didn't work! See how I got it working here.

This is going to be a long post, I hope I've explained what's going on well enough for others to replicate it if they want to!

I'm not sure what you call this plate, but this is the original plate which had the ring gear attached to it and sat behind the torque convertor. You might or might not be able to see there are 6 tabs protruding from it which whizz past a sensor which I guess is for an engine speed feed to the ECU rather than a crank position.
[Image: re_P1010229_zps3f169a12.jpg]

The ring with the tabs on it looks pretty crude, but it was obviously machined after being welded on to make it perfectly circular, at least on the outside!
[Image: re_P1010230_zpse5c8f855.jpg]

Anyhow, that bit is getting dumped as I'm changing to a manual gearbox. So, I bought one of this on a wing and a prayer. It was listed as a dual mass flywheel conversion kit for a Merc Sprinter van, 2.2CDI and others from 2002 to 2006:
[Image: re_P1010227_zps4315c5b7.jpg]

It contained all of these bits:
[Image: re_P1010237_zpsafb8c6dd.jpg]

The first problem I encountered was that there is a protruding flange on the end of the crank shaft, and a corresponding recess in the flywheel. The flange was 11.2mm and the recess only 10mm. This meant that the flywheel could not be tightened right up against the end of the crank, so the crank shaft flange was duly ground back to be shorter than the recess in the back of the flywheel.
[Image: re_P1010235_zps1236de65.jpg]

Problem number 2 is that the new flywheel is completely surrounded with ribs which, I can only suppose are used to generate a signal for the Merc Sprinter it was intended to be used in.
[Image: re_P1010238_zps65dff908.jpg]

These ribs also slightly contact the sensor. Plan "A" was to machine away the ribs I don't need in order to leave 6 remaining, simulating what was in place before, I could then put a spacer behind the sensor so that it didnt stick out so far and wasn't hit by the remaining ribs. The main issues with plan "A" were that the ribs weren't in the same place on the flywheel as the tabs on the original item (I'm not absolutely sure that there isn't some kind of timing function along with RPM!), and that I would then need to have the flywheel balanced.

I have a great engineering friend who came up with a far superior plan "B": We would drill the 6 'valleys' which correspond to the tabs we had removed, tap them and screw in bolts which would protrude above the existing ribs. We'd have to move the sensor even further out, but that's no big deal, and we wouldn't be disturbing the balance of the flywheel. So, to the implementation of plan "B".

We marked the valleys which were to be drilled and tapped, then mounted the flywheel on the engine. We turned down a big bolt so that it matched the shaft size of the sensor and would fit snugly in the sensors mounting hole. We then drilled a hole down the centre of the bolt and poked the bolt into the sensor hole. Now, we had a guide which we could use to make sure the holes we drilled were directly beneath where the sensor would be.

Here's the sensor fitment:
[Image: re_P1010236_zpsdf1caf2a.jpg]

and the bolt we guntered into a tool:
[Image: re_P1010239_zps4f1f3198.jpg]

and some drilling underway:
[Image: re_P1010234_zpse83ba8da.jpg]

Here's a bolt inserted in the hole. I plan to get longer bolts, loctite them home and then remove the heads so that the part left sticking out proud of the ribs is closer to the 5.5mm of the tabs which were originally present.
[Image: re_P1010240_zpsd5256111.jpg]

Aside from these alterations, Everything else seems to work out in terms of the position of the bearing which accepts the end of the spigot shaft, the position of the clutch friction plate in relation to the splined part of the spigot shaft, and the position of the pressure plate in relation to the release bearing/concentric slave culinder which is mounted in the gearbox. Happy days!

This post was last modified: 05-15-2014, 05:44 PM by pryantcc.

1992 W201 190D 2.0L and 1971 W108 280SE with OM606, electronic pump and 6 speed manual gearbox.