PeachParts Mercedes-Benz Forum - View Single Post - A little 240D engine help, injection timing device

tcane · #5 06-06-2002, 01:07 PM

Glad to hear you were able to remove the IPTD shaft.

The roto gizmo is called the Roto Cap by M-B and it is very doubtful they are bad. The Roto Cap turns the valves slowly to let them wear evenly. Once you clean the oil out of the Roto Cap, check them by turning by hand they should turn freely with a slight click during the rotation (prevents the Roto Cap from turning in both directions).

I caution you not to make the head gasket contact surfaces too smooth when cleaning using a bead blaster. The cast iron diesel engines were designed with a specific roughness to the head gasket surfaces for sealing purposes (this was the technology of that time period). A too smooth surface will result in the head gasket not sealing properly and subsequent failure. A clean head gasket mating surface is needed, but not too smooth (once clean you can see the milling marks on the head gasket contact surfaces).

I assume you know to check the head/block for warpage? Check the cylinders for wear and replace the piston rings since you're there anyway (I prefer Deves cast iron alloy rings over the OEM chrome faced rings because the cast iron rings do not wear the liner as much as the chrome faced and if the bores are otherwise worn, but are OK for taper and out-of-round, cast iron rings will wear-in and mate to the cylinder walls better). That is, if you're taking the pistons out which I assume you've done since the engine is on a stand.

Exhaust valve guides usually wear faster than the intake guides - a go,no go gauge is what M-B recommends and clearance is tight compared to Detroit engines (valve guide ID 10.000 - 10.015mm, service limit 10.025mm, valve stem OD 9.92 - 9.94mm). Valves can be re-faced if needed. Lap the valves lightly with lapping compound to mate the surfaces to each other (even if a machine shop does a valve job, some do not take the time to do a good lap job).

My $0.02 Worth!
Tom