Quote:
Originally Posted by deanyel
How much, approximately, does a 112 motor "complete tear-down and re-ring" cost? I've never heard of such a thing on a 104 motor.
|
The cost depends on what we find, once the cylinder heads are removed. In most cases, the piston rings are the only "hard parts" that need replacing. In this case, we do the job
without removing the engine. We replace the rod bearings as well, since we've got them out, but they're usually in pretty good shape. Depending on mileage, we may also recommend replacing the valve stem seals as a pre-caution. It only adds a couple hundred dollars to an already large bill, but we leave the final decision up to the owner.
Occasionally, we find severe scoring of the cylinder walls. In this case, we replace the engine block, with pre-fitted pistons. The crankshaft and connecting rods are re-used. The rod, main, and thrust bearings
must be replaced as well. Before we tear down any M112/113's though, we listen to it carefully. Sometimes, a slight knocking noise can be heard from the engine. It's not very noticeable, but it has a very distinct sound. Once you hear it, it's easily recognizable. This is the tell-tale sound made when the cylinder walls are scored. When we hear this noise, we inspect the cylinders with an articulated borescope. If we find cylinder wall damage, we can give the owner the bad news, but keep the diagnosis cost down.
FWIW, I think the reason you've never heard of this on an M104 is because it's extremely rare for them to have bottom-end problems. I've never seen a 104 engine failure that wasn't caused by over-heating, or oil starvation.
Quote:
Originally Posted by TimFreeh
Is it just me or does anybody else out there find this scheme absolutely absurd? Why in the world do we need 1) a computer interface module on the door switch 2) a computer network and its associated protocols and software to transmit the requested function to 3) another computer interface module to receive/decipher the request from the computer module mentioned in #1 and then send the appropriate voltage to activate seat motor? Why is this scheme better than 1) a switch with a wire that sends current directly to the seat motor? Does anybody know if Honda, Toyota or even GM use computer networked components to control a power seat?
|
Believe it or not, in many ways networking can actually simplify things, from a diagnostic standpoint, just not for a DIY'er. Networked MB's use only a fraction of the wires that would be needed for a non-networked car to perform the same functions. The various control modules can be accessed via SDS, and the wiring, switches, motors, etc. can be easily checked, without any unnecessary dis-assembly. It also allows MB to keep parts costs down by reducing the number of variants of similar parts. For example, only one PSE locking pump is available for every S/W210 worldwide. It can be programmed for the particular options/equipment at the time of installation. If not for networking, MB would need dozens of part numbers for basically the same part, thereby increasing (at least according to MB) the cost of the part.