Hello

Recently i acquired a rather tired 1983 240D. The engine runs rough. The whole body shakes at idle.

So far i have done the following:
- Adjusted valve clearance
- Replaced both motor mounts with new lemrorder ones
- Replaced gearbox/engine mount (so called T mount)
- Replaced primary and main fuel filter
- Replaced oil filter and oil
- Replaced primer pump
- Replaced fuel supply hose to primary filter and from primary filter to injection pump base (where the primer pump is)
- Replaced return hoses from injectors
- Replaced injector nozzles with denso dn0sd261 and had them set to pop at 155bar

None of the above made any difference as far as the shaking at idle goes. I tried increasing the idle withe the screw on the back of the injection pump (Bosch M/RSF with mechanical governor) but it only shakes differently.

Compression test reads as follows:
1 - 325psi, 2 - 335psi, 3 - 325psi, 4 - 260psi

Right now i am suspecting the fourth cylinder to be causing the shaking or the injection pump supplying fuel unevenly to the cylinders.

I would be grateful for any suggestions before i pull the head to see if no.4 cylinder has a broken ring or bad head gasket in that area.