BMW N55 Engine Rebuild Project Part 1 – I Bought A Broken BMW N55

Hey guys and welcome back to another video on the SimpleCarGuy channel. It has been a few months since I have started working on the e92 project and I know I haven’t posted an update in a long while. So, in this video, I will go over why it took so long, what’s happening now and the plan for the future. After taking the engine out of the car and tearing it down to see what it looked like, I found that it was not rebuildable at all and I had to find another engine. Unfortunately, that’s where I ran into some issues. At the time of buying the car, a BMW N55 engine could have been had for under $3000 with less than 100,000 miles minus the turbo and some accessories, which I would gladly pay. However, whether it was due to pandemic or winter being right around the corner, the engines just disappeared from the market and the pickings were slim. The best engine I could find was over $4000 with 135,000 miles out of a wracked car with no warranty or guarantee. Now, I could have risked it and went for it, but it felt like such a step back. I waited and waited and nothing came on the market.

Then one day I was on Facebook market looking for random car stuff as I normally do and I searched for a BMW N55. To my surprise, there was one for sale and it was only 5 miles away from me. What was more surprising was the asking price – $350. I figured, for $350, it can’t hurt to at least go look at it. I had a good look at it and it was a clear case of spun rod bearing. I realized that this engine in a rebuildable condition, so I pulled a trigger on it and bought another knocking BMW N55 engine. Of course, it’s not in a perfect condition by any stretch of imagination, but it’s decent enough to attempt rebuilding.

I brought the engine home, put it on a stand and started taking it apart to inspect it closer. So, how good of shape is it really in? Well, let’s find out!

Even though the guy that sold me the engine swore that the only damage to the engine is the spun rod bearing, I have seen what a spun rod bearing can do, so I had my doubts. My biggest worry was damage to the cylinder head and the cylinder walls which would make the engine not worth rebuilding. I used a small camera to go through the sparkplug hole and what I saw scared me a little bit. It looked like it was all cracked and black and not like it’s supposed to look. However, once I removed the cylinder head, I was pleasantly surprised, everything was intact and in good enough shape! Who would have thought!? This game me the go ahead to start ordering parts and proceed with the teardown.

I didn’t include the tear down footage on this engine up until this point as it’s pretty much exactly the same as I did on the original engine. Check out those videos for detail on how I got to this state of the engine.

While I do some research and wait on parts to start arriving, I’m continuing to take apart the bottom end. To remove the bed plate, I had to first remove the main crankshaft bolt, which turned out to be a not-so-easy task once the engine is on an engine stand. I ended up using a wrench to hold it in place and a very long pipe to break it lose. Now that the main bolt was out, I was able to remove the crank hub which then allowed me to remove the sprockets and the chains. A few screws and bolts later, the oil pump was ready to be removed as well.

The last step in disassembly was to remove the bed plate bolts in the correct sequences as well as all of the outside aluminum bolts. It’s mandatory to replace all aluminum bolts when re-assembling the engine, so lots of ordering a head of me. I then removed the bed plate from the engine block to expose access to the crankshaft. This is why I did so much work disassembling this engine. It’s to replace this big ol chunk of metal. I won’t be releasing those rod bolts until I’m ready to put the new one in as I’m afraid of accidentally pushing the piston out and it falling on the floor.

At this point I’m pretty much done with the disassembly of the engine and it’s rebuild time! I have ordered most of the parts I will need to get started, but first I will have to clean all of the parts I will re-use and set up a better work space for myself. The plan after is to replace one of the pistons, put all new main bearings in and replace the crankshaft. Put the bed plate back on, seal it with the correct sealant, install gaskets and seals back in and reassemble the rest of the bottom end. This of course will be in another video, so don’t forget to subscribe to follow this rebuild project.