I wanted to gauge how many hours I should expect the motor swap to take, as I would like to get an idea of what I'm looking at price wise for the labor from my mechanic. Thanks in advance!!!

It depends on a lot of factors. If it's just a quick and dirty swap pulling the old and dropping in the new - and the donor engine has the right oil pans and mounts - it could probably be done in a long day. But there are dozens of things you should do to the donor engine while it's on the stand - b/c once it's installed it could take 10x longer to do later. (The r/r of the timing cover to reseal is a 15.6 hour job w/ the engine in the car - few hours on the stand.) There are also a bunch of jobs to do to the empty engine bay that are much easier with the engine out and it's a good opportunity to do some upgrades - like 211 E55K engine mounts for example. Been meaning to write up everything I did during my swap but haven't had the time. The parts list is lengthy - but if buying from FCP and ECS (can get odd stuff FCP can't) the prices are actually very reasonable. Order part # 1129900378 now! It took WEEKS to arrive. It's the extra coolant fitting on the back of the right cylinder head that the C43 has and the 55 donor engine won't. You may be able to swap but not worth the risk IMO - only cost $4.90 from ECS. I spent those weeks cleaning the engine bay and replacing more "while I'm there" parts. If the part/job looks hard to replace once the engine is installed - just do it now! I also got a All Data subscription for all the procedures and torque values and studied up before starting a task.

Thanks for the response. I would love to get your part list as well as hear about the dozens of things you did to the motor before putting in the car.I want to dial in the motor as best as possible before installation as well as prep the vehicle/engine bay/ as well. My mechanic is well informed though would love any additional resources so I can get the best result!

One of the biggest things you can do while engine isnout is timing chain.

Usually these dont need to be done on the m113 in a long tme but its good to check if possible.

Crank position sensor is a must do. Its a ***** to get to with engine in.

Also rear main seal. Trans needs to be dropped to do that job so might as well do while engine is out. The rest is doable from above but obviously as mentioned in the first post....its all a lot easier with it outside of the car.

Appreciate the tips!

wheres your donor engine from? depending on what it came out of, it could require extensive swapping of not only the oil pans bit the oil pump and/or pickup tube.

but if it's the right engine already, do the valve cover gaskets, oil breathers, spark plugs, and USE CORRECT MB PASTE and grease the starter gear. It can dry out over time causing a no start issue that requires pulling the starter and that's an all day job while the engine is in the car.

but the swap itself isnt bad. My mechanic charged me 1800 which included a new water pump. My engine was from a 1999 E55. All I had to do was add the water pipe on the back of the passenger head.

and what everyone else said, too.

see the 55 swap thread - added a quick list of all the jobs I did on the new engine.

the engine is from an 01 clk 55