Replacing crankshaft-OM616 240D
 

I rebuilt the engine in a friend's 240D, and even replaced the oil cooler hoses (crimped on new hydraulic hose). About 100 miles after the car was picked up, I got a call from him saying that oil is all over the engine bay, and on the ground. I had the car towed back to my place, and I found that the oil cooler hose had a breach in it right at the ferrule. I replaced the hose and filled it back up with oil. It had a rod knock, and I found it to be on #1 cylinder. I dropped the pan and oil pump, and polished the crank journal, and replaced the bearing. It still had a rod knock. I decided to pull the engine, and replace all the rod bearings (I assumed they all were bad). After replacing the rod bearings, I put the engine back together, and installed it in the car. I was sure that the knock was a rod bearing, so I went against the suggestion of my brother to start the engine before installing it to prove weather that fixed the problem. After installing the engine, and hooking up EVERYTHING, it STILL HAD A KNOCK!!! I can't believe I did not listen to sound advice! I guess I needed the experience of removing/replacing an engine in a 240 more than one time in a week!

I removed the engine yet once more, and am now going to replace the crankshaft and main bearings (the new rod bearings are just fine. I could just polish the journals on the crank, but I do have a good crank from a parts engine that I will use instead.I have a set of oversize rod and main bearings, so I will have the crank turned and use the bearings I have in another engine (I already have the block at the machinist getting bored, honed, and hot tanked).

After removing the pan and oil pump, I removed all four rod caps and put vinyl tubing on the bolts to protect the crank. I put the crank on BDC so the dowel pin was facing up (engine upside-down on the stand). I then marked the timing chain with a black marker in line with the dowel pin, and used a file to make a small mark in the chain. That way, I can place the chain on the new crank in the exact same spot, and not have to re-time the injection pump. I also removed the chain tensioner and timing gear so the chain could slack enough to get the crank out. I used a piece of coat hanger wire to make a "bridge" under the slacked chain. That made plenty of room to get the crank out.
Part 2 later.......Rich

Are you using plastigage ?

You might want to have the connecting rod checked to make sure that is o.k. I rebuilt a 1960 Alfa romeo Gulia Spider engine that had an engine knock. Replaced all the main and crank rod bearings, and just like you, the knock reappeared. Turned out that the connecting rod bearing cap itself was not sitting square on the crankshaft, and the rod was slightly bent causing the bearing to fail in short order and the knock would reappear. Had the machine shop true up the connecting rod, and that took care of the issue.

Loving the coat hanger… Great idea

are the rod bearings scared? did they spin in the rod? if so the rod is bad. if the bearing is worn and loose the piston can hit the head. plastigage?

I do have used 240 engine parts 801 706 6871

Doubt it.

They are very brave.

:D:D

Painful even to read. It is a good week to lay off buying lotto tickets.

Strange failure of the new oil cooler hose as well. Pressure is not that great. A blowoff might be more understandable. I might replace the brand of the oil cooler hose used. Unless examination reveals an issue of some sort.

The bearings (rod and main) were barely scared, and nowhere near the point of spinning. The fact is, that built up bearing material has taken away the oil "cushion", and thus the knock. I will say that after replacing the rod bearings, the knock was very slight. Still too much to leave alone. The crank I harvested from another block is near perfect, and I could have reused the bearings if I was in a bind. However, the customer paid for new, so I will be replacing them with new.....Rich

More photos. The rod bearings are still good, but the mains need to be replaced. I have them ordered. I had a st in stock, and another set ordered, but both turned out to be .025 over/undersize (one in mislabeled box, the other not described as such on ebay).

You are absolutely correct. I got the hose from my local hose repair shop, and it could have been old stock. I ordered some Cohline hose from the Hause in AZ, and it felt much softer and even smelled better (new).

Photos of the rod bearings, rod journal before, and after.

Most euro 240D's didn't have oil coolers so that's another way of avoiding a line failure.

They had a blanked off housing without a thermostat (important)