Right. So stripped the block down this weekend and gave it a cleaning (pic is when I'm about half done) still not sure if I'm going to take apart the crank and pistons because honestly all of it is pretty tight and smooth. I'll measure the bores when my gauge arrives and go from there.
But a few questions about the head. I've got it pulled apart. Valves look pretty clean honestly - I can't tell if it was burning oil because it was leaking so much oil - but no puffs of smoke. Plugs are black-ish but not wet. Either way. I ordered new valve guides - seals and various other head consumables - but not new valves. Rockers and cam don't show much wear or scoring really. For a 250k mile engine - maybe that's surprising. But good lubrication and maintenance and an understressed engine can soldier along I guess!
I've heard from some people that when you replace valve guides you need to recut the valve seats. Others say just to replace the guides and lap the valves and make sure there's no leaks. If I get the head shop just to make sure the head is flat and possibly make it flat - and pressure test and nothing else it's like 100 bucks. If I want them to recut the valve seats and do the valve guides it's 450. Anyone do this and have any thoughts or approaches? 450 feels high but I'm willing to spend it if it's the right way to go.
I'm gonna add my 2 cents on the manual swap. I had a 95 124 wagon. Did a C36 engine swap ...definitely what it needed, but the auto let's it all down. The stock auto sucks, gear ratios about as bad as they could be because there is no proper overdrive, so your rear end ratio ends up being well into the 2s...I did a 5 speed auto swap, the electronic one. Only one guy makes a controller for it, I wasn't impressed...and after months of trying to get it right, I dumped it for a 5 speed. Only one I could find at the time was the worst one you could get, out of a 190d 2.2. It was fine. Held up behind that engine with no problem. If your mean to it, yeah it would probably break, but I wasn't banging gears or doing clutch drops. I wouldn't hesitate to do it again. Woke that car up hardcore, swapped in a 300ce diff, which was a 3.27 or something like that and it was perfect. FYI I was able to get a new flywheel for an M103 from Mercedes, modified it to match the M104 flex plate trigger windows, and swapped in the magent. It was super easy. Stock M103 clutch and that was it. Nothing special. Pedal box and master all from the W201 diesel the trans came from. Biggest issue was the small flex disc on that trans...it needed to be bigger, but it held up.
5 speed that car! The biggest Improvenent you can make is cutting the shifter levers and shortening em to get a shorter throw, and using new/solid bushings to tighten it all up. I wish there was an adaptor for a T5, that would be a sweet setup as well.
This 300e started mixing coolant at 294k so we did a head gasket and the rest of the engine was incredibly clean. I would do what you went in there for and leave the rest.
Once I stripped the engine - just saw enough cam wear that I decided just to get a new cam and rockers.
Since the incremental cost is low. Went ahead and got a new main bearing set and connecting rod bearings. Rings. Seals and whatnot. Head is getting fully redone with new valve guides.
The good news is it looks like though there's a slight oval to my 250k mile block. It's all within spec. I'm getting around 0-3um of wear front to back and around 20um of wear along the thrust axis.
Took me a second to learn how to dial in my bore gauge but now I'm sort of in love with it. What a cool tool. I need more engine blocks to measure.
Yeah the m103 was pretty bulletproof. Head gaskets occasionally and valve seals are about all that go wrong mechanically. Though I haven't had a 250k mile one apart. Seems though like it's still the case. But if wearing the head just from miles, other than that...
