Hello everyone and welcome back to the SimpleCarGuy channel. This is part 4 of the BMW N55 engine rebuild project where I install the new head gasket and reinstall the cylinder head back on the engine. In the previous videos I have taken the engine out of my BMW 335i, tore it apart and found that it was not rebuildable… some time later I found this engine for cheap locally and have replaced the main bearings, crankshaft, piston and installed new rod bearings. Now this engine is ready for the cylinder head to go back on.
I chose not to do much work on the cylinder head except to clean it up a little bit and remove some carbon. After inspecting it, I didn’t see excessive wear or anything of concern and honestly, I’ve used most of my budget that I had for this rebuild on bolts, seals, gaskets and all the replacement parts.
Clearly my engine is out of the car and it took a decent amount of work to get this far but I’m not sure I’d recommend doing this with the engine in the car if it is at all possible. BMW also recommends taking the engine out for this job and that’s why you see so many valve cover videos on YouTube, but I couldn’t find any as far as the head gasket. Anyway, this series is meant more to document my journey with this car and rebuilding the engine as a hobby mechanic and hopefully help someone in the future do the same or at least start doing DIY jobs at home. Also, now would be a great time to hit that like button for all the BMW DIYers and for the Youtube algorithm.
Check out my video where I disassemble a BMW n55 engine and take the cylinder head off to get an idea of what to do to get to this point. If those specifics aren’t your thing, I’m highlighting the basic steps in this video.
Step 1, remove the engine from the car by removing the exhaust system, draining all of the fluids, removing the intake, radiator, all of the piping and disconnecting it from the wiring loom and transmission. Wow, that was easy! The engine is out now!
Step 2, mount the engine on the engine stand, removing the exhaust manifold with the turbo, injectors, gas lines and anything else attached to the cylinder head. We are moving right along!
In step 3, we undo all of the bolts from the valve cover, remove it and install the timing tool onto the camshafts. Now we can undo the central bolts and remove the camshaft adjusters.
That’s it! Now we only have 14 big bolts holding it in place and after muscling those out of the way, we can lift the cylinder head off the block! No body said this one was easy, but now we are finally ready to replace that head gasket.
Now starts the most tedious part of the job and that’s getting everything nice and clean. This doesn’t look that hard on video, but it sure takes a while to do. I’m mostly just removing the carbon build up as much as I can to help the engine breathe a little better and have the oil flow a little smoother.
Removing remanences of the old gaskets is the most important step; otherwise, your new, expensive gasket will not make a very good seal and you’ll have oil leaks after all of this hard work. I didn’t use any metal tools while doing this as it’s very easy to damage the mating surface, but I did use a brass spinning wheel on the valves to get rid of all that build up carbon. The brass tool is approved for aluminum, so I had no concern using it on hardened valves. Having this great access to the pistons, I gave them a quick clean as well. MUCH BETTER!
Now that all of the parts are ready, it’s a good idea to wipe everything down and make sure there is no oil and dirt in the blind holes or anywhere the gasket will touch. Then, it’s time to actually install the gasket. I decided to go with the ELRING head gasket as they are the OEM for BMW and I’ve used their products before. It simply drops on top of the block, making sure all of the holes line up and the head can go on top. It’s heavy and you should really have a buddy help you out, but I work on this stuff at night and I like being in the way of the camera, so here we are. Once everything looks good and it’s lined up, it’s time to grab a torque wrench and the angle gauge and torque our head bolts to spec.
These bolts drop in easy, but make sure the washers are there. Very easy for those to fall out and get overlooked. You’ll need a special long torx bit set to reach the bolts and set correct torque values. I got mine on Amazon and if you’re interesting, check out the link below, these work great.
There are 3 types of bolts here. We have the M11 and M9 bolts, those are the ones that go in the middle and are torqued to 30 NM, then 90 degree angle of rotation and another 180 degrees on second round. The 3 third type are the M9 short bolts that go on the side where the timing chain is and are torqued to 22nm. I don’t think I have to explain how important it is to do this to spec, just imagine the pressure between the block and the head when the engine is running. And the last thing to do to finish the job is to put back the stopper bolt for the eccentric shaft and the oil spraying nozzle that we removed to get to the bolts.
That is all for part 4 of the BMW n55 engine rebuild project, in the next video I will be installing the oil pump, the timing chain guides with the timing chain and timing the engine. If you’d like to see that, subscribe to the channel and I’ll see you in the next one. Thanks for watching.