BMW N55 Engine Rebuild Project Part 8 – Front Crankshaft Seal DIY (No Special Tools)

Hey guys and welcome back to the SimpleCarGuy channel. I’m still working on my BMW N55 engine rebuild and as one of the last steps, I’m installing a brand new front crankshaft seal. Just like with the rear crankshaft seal, I will not be using any special tools for this job as I think it’s doable with the stuff you already have in the garage. Of course, if you do these often or aren’t sure of my technique, buy the correct tools for the job. However, if you’d like to see my DIY method, this is the video for you! If you’re interested in the rebuild project, check out the link in the description to start from the beginning and don’t forget to give this video a like to support my channel. Now to the job at hand.

If you are doing this with the engine still in the car, you will of course have to remove some parts to get to the seal. Luckily, it’s not nearly as bad as the rear seal. To start with, you’ll remove the underbody protection panel and most of the air ducts that’s in the way on the top of the engine by the radiator and with enough space remove the radiator fan as well. Your transmission oil cooler might be in the way, but you don’t have to remove it. It can be moved to the side. With a lot more space, you can now remove the serpentine belt that’s wrapped around the vibration damper. Now, to remove the 8 screws holding it to the crankshaft, you will need to secure the crankshaft in place or it will move as you try to loosen the bolts. You can get a simple stopper tool for a few bucks and block the crankshaft from moving at the flywheel and release the screws.

Now that you finally have access to the front crankshaft seal, you’ll have to remove it. This can be a little tricky without the special tool, but whatever you do, do not release the main bolt unless you want to be timing the engine as well. The way I removed my seal was by screwing a thin screw into the seal and then pulling it out with a hammer by leveraging it against the engine block. It popped out without much hesitation.

Finally, we are at the install stage and the first step, as always is to really clean the area as well as you can. A good degreaser will help you get rid of any oil on the engine block and insure a good seal. Once everything is clean, the seal can be installed. Once again, you can use the fancy install tool, but I will use what I have.

To install the seal, I use the little plastic cone that it came with and my old seal to get it seated on the crankshaft. No force is really needed here, it should go in easily and once you start feeling a little bit of resistance, grab a mallet and tap it in place. Check that the inner seal is seated properly and not bent over itself as well as the little groves lined up with the seam on the block and then go to town with your mallet. You don’t want to hit it hard, so slow and steady wins the race here. As long as it’s going in evenly, we are getting it done. You also don’t want to hit the seal directly and use the old seal to distribute the weight, this is very important to avoid damage to the new seal. After some time, it will start to feel like it’s not moving anymore and as long as it looks to be in the right stop, you are done with this part.  

The next step is to use a liquid sealing compound to avoid any leaks in the future. There are two different sealants you can use, the one I showed you at the beginning of the video and one I will show you in just a few seconds. Whichever one you use; you will need a primer for good adhesion.

After everything is cured, re-assemble the car and have many more happy miles without an oil leak at the front crankshaft seal. Anyway, thank you guys so much for watching, leave me a comment down letting me know how hard or easy this was for you, subscribe to the channel if it’s your first time watching and I’ll see you in the next one video when we finish the engine and put it back in the car.

BMW N55 Engine Rebuild Project Part 7 – BMW N55 Injector Install and Teflon Rings DIY

Hey guys and welcome back to the SimpleCarGuy Channel. Today we are installing injectors on my BMW N55 engine with an early production date. The reason I mention this is because the process is different on newer engines and if you’d like to see what that process is like, check out my video on the BMW N20 injector replacement as it’s exactly the same. In this video, the injectors are already removed from the vehicle, so once again, if you need those steps, check out the N20 video in the description. Now, let’s go to the garage, get the injectors prepared, installed and at the same time hit that like button for the YouTube Algorithms.

Now we are going to replace the decoupling elements and the Teflon rings on my used injectors. These must be replaced or you will have issues in the future such as lose of compression or fuel blowby. The decoupling elements simply pop off with a flat head screwdriver and a new ones can pop back in once we do the seals and clean the area.

Next we remove the Teflon ring seal by carefully cutting it with a razor blade or a box cutter and peeling it off the injector. You don’t want to cut into the injector, so be careful here. With those out of the way, we can wipe the injector with a clean paper towel and pop the new decoupling elements in place. The round part of the element faces the nozzle of the injector. For the next steps you are supposed to use a few special tools, but I do it my own way. You can find the proper tools in the description if you’d rather use those.

This really does work well, you just have to find the correct diameter plastic pieces or cut them down to size.

I have a video on how to adjust the compensation on the injectors from a couple of years ago, so check that out if you need steps. With that, thanks for watching, I hope you found the video useful and I’ll see you in the next one!

BMW N55 Engine Rebuild Project Part 6 – Valve Cover Gasket & Oil Pan Gasket

Hello and welcome back to Part 6 of my BMW N55 engine rebuild project that I have been working on for a few weeks now. By the end of this video, this engine is finally starting to look like a real engine and not just a pile of parts around a block. I can almost hear this engine start up for the first time and purrrr with all its new parts, or at least I hope it will! In today’s video I’m replacing the valve cover gasket and installing the valve cover itself as well as replacing the oil pan gasket and installing a new-to-me oil pan. More on that later.

If you’d like this project to succeed, don’t forget to hit that like button for me and of course the YouTube algorithm. Now, back to the project!

I won’t be going into details on how to get to this stage as I’ve shown the steps in my engine removal video. I suggest you watch that video for more details on which parts to remove to get to the valve cover. Basically, you’ll remove the intake housing, fan cowl and move the coolant expansion tank to the side. No need to disconnect it. Then remove the air duct that feeds the turbocharger and now most of the stuff is now out of the way, so you’ll just have to remove the gas pressure lines after disconnecting the battery; of course, and any vacuum and electrical connections. Now the valve cover can be unbolted. If you will be reusing it, make sure to unbolt all 26 bolts in the correct sequence and remember that these bolts are attached to the cover itself and will not peacefully come out past the plastic part.

With the valve cover removed, we can inspect the surfaces on the cylinder head and remove any bigger debris with a plastic razor and use a scotch brite pad for anything remaining. The valve cover itself has 4 different gaskets that should be replaced each time the cover is removed to avoid any oil leaks. Replacing them is very easy, remove the old stuff, clean out the channels of any dirt, insert new gaskets and we are ready to go back on the cylinder head. In my case, I had to install the spark plug housing which came off during the rebuild. With everything ready to go, the cover simple can be lowered making sure everything is aligned and torqued to spec.


Torquing these bolts to spec and in the correct order is probably the most important step as this plastic cover can easily warp or even crack if not done correctly. Refer to the diagram for the correct sequence and then  hand tight or use a power drill on the lowest setting on all of the screws. For round two, each one gets 8.5 Nm in the same order. DO NOT go back to the first ones to check torque or retorque them again. They have to be done in that order and left alone.

If all went well, simply re-assemble whatever you have taken a part to get here and enjoy your new valve cover gasket!

Now onto the Oil Pan gasket and install. As I mentioned earlier, I had to get a new oil pan as the engine I’m rebuilding is from a BMW X5 and the oil pan and pick up tube are different on that car. This one is a lot more complicated to do at home if you don’t have your engine out, but it is possible if you drop the front axle support and remove the front differential and power steering pump. With correct access, this is a simple job just like the valve cover. Just as before, cleaning all of the surfaces is very important to prevent leaks and then we can drop the gasket on the engine block. In this case, there are no guides, so you have to be very careful when installing the new gasket as it will move around if you’re not careful. It took me 2 tries before I got it perfect and I had perfect access, so I imagine it’s a little bit harder while working under the car. With the gasket aligned and the oil pan sitting on top, we can insert new aluminum bolts in a couple of spots and screw them in a few threads. Now comes the important part. If the engine is out, you’re supposed to use an alignment tool to make sure the oil pan is perfectly aligned with the block. If the transmission is still attached, you don’t have to worry about it as it will align itself to the bellhousing. Here is what I did. Then hand tight a few screws to keep it from moving around. All screws on the oil pan are torqued to 8 Nm and then 90-degree rotation for the short ones and 180 degree of rotation on the long ones.

Well, look at my engine looking all spiffy now with the new gaskets and ready for more parts. Thank you so much for watching part 6 of the N55 engine rebuild project and I’m looking forward to seeing you in the next parts where we install the front and rear crankshaft seals, install the injectors, the exhaust manifold and drop the engine in the car. Leave a comment down below and let me know what you think of the progress so far and if you’d like to follow the project, don’t forget to subscribe. See ya next time!

Test and Clean VANOS Solenoids – BMW VANOS Symptoms

Hey guys and welcome back to the SimpleCarGuy channel. In this video we will discuss common symptoms of a bad solenoid, see how we can test one at home and how to clean it.

Ever since the early 90s, a lot of BMW engines have been using the VANOS system to adjust the valve timing on the fly. This gives the engine more power over the rev-range and for that reason in general, we like variable timing on engines. We get low end torque and high end horse power, very similar to VTEC on Honda engines. The design has changed over the years, starting with single VANOS system used in the 90s, dual VANOS system used in early to mid 2000s as well as the famous n54 engine that was in production until 2010 and of course Dual-VANOS with VALVETRONIC that I have in my N55 engine that was released in 2009 and is still used today.

Now that we know a little bit of history, let’s take a look at how to actually diagnose a bad VANOS solenoid. A lot of the times, the symptoms are not drastic, so it can be difficult to tell, but usually you’d look for things like loss of low-end torque or power in high revs, slow response or inconsistent idle or even poor fuel economy. Some of the more noticeable items could be rough idling; especially, on cold starts as well as long cranking. Of course, if it’s bad enough, the car will go into limp home mode and you’ll normally get codes related to Camshaft Position or VANOS specific codes. If you suspect the solenoid might be fault on your car, there are ways of testing it. This isn’t something you’d see a dealer do, but it may help you troubleshoot your engine issue. Of course, if the issue is intermittent, this method does not guarantee that it will always work, but it’s an easy way to detect a bad one.

BMW N55 Engine Rebuild Project Part 5 – Timing Chain and Oil Pump Replacement

Hey Guys and Welcome back to the SimpleCarGuy channel. In this video, we will have some fun installing the oil pump, oil pick up tube, the timing chain and timing the engine. I liked doing the timing chains so much that I did it twice. More on that later!

If you are new here, well, I have been rebuilding my BMW N55 engine for the past few weeks and it’s been a great learning experience. I have replaced the main bearings, crankshaft, sealed the bed plate, installed new rod bearings and a new head gasket. The last huge item on the list is the timing chain, which is today’s video.

While I’m doing this with the engine out, it is possible to do a timing chain job without having to remove the engine from the car. As in previous videos, I won’t be showing those steps, but I’ll do a quick overview on how to get where we are. I recommend you watch my previous videos where I show a lot more detail on disassembly.

HOW TO GET TO THIS POINT:

So, the quick overview. Here we go.

Step 1: Unplug the battery and drain the oil from the engine. Remove air filter housing or clean air pipe running over the valve cover depending on the car and undo the gas pressure lines.

Step 2: Remove the underbody protection, intake silencer housing, fan cowl and the serpentine belt that runs the accessories. With that access, you can now remove the vibration damper and the front crankshaft seal. If the belt tensioner is in the way, you may need to remove it as well.

Step 3: Remove the valve or also known as the cylinder head cover by unplugging the vacuum lines, wiring from the injectors and anything else that’s in the way. If you will be reusing the valve cover, make sure you undo the bolts in the correct order (show here) and remove it from the cylinder head.

If you aren’t replacing the oil pump or oil pump chain and sprocket, no further disassembly is required. Otherwise, you will have to remove the front axle differential, remove the power steering pump and remove the bearing support to be able to remove the oil sump and have access to those parts.

Before you can remove the timing chain or the oil pump components, you have to rotate the engine into the TDC (Top Dead Center) position using the main bolt. You know it’s in the correct position when cylinder number 1 is at the very top. Now we can install the timing tool onto the camshaft to make sure they do not move while we remove the central bolts on the intake and exhaust camshaft adjusters. You should have no issues unbolting these. Then remove the chain tensioner as well which will give your chain some slack and allow you to remove the camshaft adjusters by hand.

Next, the main bolt must be loosened and taken out. This is a tough one. With the engine out, it took an 8 foot pipe to get it done, but I have also done it in with the engine in the car on my N20 timing chain job and it was a little easier. Whichever way you go about this, make sure the socket is very secure on the bolt and doesn’t slip and spray some WD-40 or whatever else you have if it’s a bit rusty.

With the main bolt out, there are only a few things holding the timing chain and timing chain guide in place. The 2 bearing journals that are hiding behind the screw plugs, the crankshaft hub, two little screws at the top by the camshaft adjusters and of course the camshaft adjusters themselves. With those removed, hold the timing chain and guides with one hand and remove the hub with the other making sure not to drop the sprocket. I recommend keeping the chain tight to avoid this and just pull it up as soon as the hub has cleared it.

Now that everything out of the way, we can finally get to fun parts! Since I’m rebuilding the engine, I’m reinstalling the oil pump using new bolts. The install is very simple, but to be safe I do a mock up with old bolts while I’m working on getting the chain assembly in. Just in case I have to move it or something isn’t lining up properly. If I used new bolts and have to loosen them, I’d have to get new bolts again. The 3 bolts at the top are torqued to 10 Nm and then 180 degrees angle of rotation for the longer bolt and 90 degrees for the shorter bolts.

We are almost done with this job and as you can see it does take some time and effort to get there, no wonder a shop would charge you a couple thousand bucks for this! Anyway, to install the new chain and tensioner, make sure it’s all assembled correctly and the sprocket pointing the right way. Then it can all be lowered into the engine, lining up the sprocket with the crankshaft hub and locking it in place with a new main bolt. You don’t want to tighten it to spec just yet. First, reinstall the 2 bearing journals and the 2 little screws at the top to hold everything in place. Torquing all to spec, of course.  Now the main bolt can be torqued to 100 Nm and additional 270-degree rotation. I recommend having someone help you out with this one, it felt a little sketchy as I was doing it.

With the main bolt locking everything in place, it’s time to install the intake and exhaust camshaft adjusters back in with the chain around them. Should be pretty easy since the chain tensioner is not yet installed. Of course, you have to make sure that the intake adjuster goes on the right side and the exhaust on the left, you cannot mix these up! While you are pulling the chain over the exhaust adjuster, make sure it is sitting on the guide rail and not anywhere else. With everything looking good, we can install the pretensioning tool instead of the chain tensioner and torque it to 0.6 Nm and torque the central bolts to 20 Nm with 180-degree rotation after. The very last step before testing is installing the chain tensioner and torquing it to 55 Nm.

Once everything looks good, we can remove all special tool and rotate the engine a couple of times making sure everything sounds good and recheck the timing. If everything still lines up and the timing tool fits as it did before the engine is timed and ready for its new crankshaft seal and re-assembly. A video on front crankshaft seal is coming out soon!

Now, remember how I said I had to do this job twice? Well, after I rotated the engine a few times, it made this clicking sound from the camshaft adjuster which I wasn’t very sure about. So, I posted a short clip to check with others and see if it’s normal. I learned that indeed, it is normal and it will go away as soon as oil pressure is built up and circulating, but I also learned that I was making a mistake. Initially when I looked at the timing components, they looked fine to me so I reused them.. but after many, many convincing arguments from strangers, I have decided to replace it all with brand new stuff, including the chain tensioner. Anyway, thanks for watching, check out the links in the description for parts needed, leave a comment down below and I’ll see you in the next one.

BMW N55 Engine Rebuild Project Part 4 – Cylinder Head Gasket Replacement

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.

BMW N55 Engine Rebuild Project Part 3 – BMW Rod Bearing Replacement

Hey guys and welcome back to the BMW N55 engine rebuild project. In this video, I go through the process of replacing the rod bearings with the engine out, but the process is exactly the same once you have access, although maybe not nearly as comfortable. Rod bearings fail for many reasons; mostly, due to oil starvation which causes them to overheat and spin on the journal of the crankshaft. If you catch it in time, you can simply replace the rod bearings and you are done. However, if it’s not caught in time or the rod bearing has already welded itself to the crankshaft (show n20), you’ll have to replace the crankshaft as well, just like what I’m doing with this engine. If you hear a knocking coming from the bottom of the engine, the most likely culprit is the rod bearing. This is why some people choose to do this as a preventative maintenance on their hard driven or high mileage BMWs. If you are interested in those steps, check out my previous video where I go through the process of installing a piston, replacing the crankshaft, installing new main bearings and sealing the bed plate. Before we start, make sure to hit that LIKE button for the YouTube algorithms and future DIYs.

In this video I will not be showing you a step by step on how to get to the bearings as it’s different on every car and may be harder or easier depending on the model. As an example, it would be much easier on a BMW Z4 that is rear wheel drive and has tons of space to work with, but it’s much harder on a BMW 335i e92 like this one as space is very much limited and you have to deal with the all-wheel drive system. In any case, to get to the bearings without removing the engine in this car, you’d have to remove all of the reinforcement plates and covers under the car, lower the front axle, remove the front axles and differential and remove the bearing support. ((maybe show video with engine already out ‘for clearance of what to do’). All that work has to be done just to allow you access to the Oil pan. Now, this isn’t necessarily a very complicated part of the job, but it’s important to keep safety in mind, have the engine supported at the top in the installation position and use plenty of jack stands. When I did this on my BMW Z4 with the N20 engine, I used jack stands, wood blocks, 2 jacks and some muscle to lower it. The jacks would allow me to lower and raise the subframe as needed to squeeze the oil pan out. Like I said, a little different on each car and you don’t have to deal with a differential on a rear-wheel-drive car, but you get the idea.

Once you have sufficient access, Removing the oil sump is fairly easy, you just remove the connector for the oil sensor and unbolt all of the bolts. Then, muscle it out of space and watch out for oil dripping down on you.  Once the oil sump is removed, you will see the oil pump and the plastic pick up tube. Strangely, the workshop manual does not mention removing the oil pump, but obviously if you need to replace the bearings on cylinder 1, you’d have to remove it as well. That’s a process of its own, but mostly you just unscrew some bolts and you can remove the oil pump without removing the chain modules.

Clearly this video is more about the correct procedure of changing the rod bearings rather than all the preliminary work, but I hope I helped you get an idea of what it would take to get to this step. Since I had the crankshaft out on my engine, I took that opportunity to install the bearings on 5 of the 6 cylinders for convenience, but I will show you how you’d do it if the crankshaft was still installed on the 6th cylinder. The very first step would be to remove the connecting rod cap and be VERY careful not to mismatch it with another connecting rod. It’s best to do these one by one if you are worried. As mismatching connecting rods and connecting rod caps can cause rod knock or even damage. Now would be a good time to inspect the journal on the crankshaft and after removing the bearings, see how good of a condition both of the surfaces are in. You can clean them with a non-metal sponge. I used a very fine scotch-brite here to clean the surfaces and then wiped them down with some break cleaner and a lint free paper towel.

I decided to go with Calico Coated KING rod bearings instead of BMWs color coded bearings for a couple of reasons. As you may know, technically, you are supposed to look at the crankshaft marking to determine which bearing shells you are supposed to install on which cylinder and each one would be slightly different to make a perfect fit. These aftermarket bearings are more or less the average of all those values and should fit all bearing colors and provide longer life with the Calico coating and not as tight of tolerance, allowing for more oil flow.  It’s important to get standard sizing as these come in the oversized spec as well and you do not want those unless you have had your crankshaft resurfaced. Standard sizing is indicated by the STD letters on the bearing itself, check every single one to make sure there was no mix up.

Now that the surface is clean, the bearing should go in very easily. The trick here is to put the end with the key in first, squeeze it just a little bit as you are putting in the other side and it should just pop in there.

I repeat the same process for the rod caps. I clean them with scotch-brite, some brake cleaner and a clean paper towel and then install the bearings exactly the same as on the connecting rod. Here you can see exactly what I meant as far as the installation goes. Very easy!

Now that we have all of our pieces ready to go, it’s time to check the clearance between the crankshaft and the bearing. It’s vital that the clearance falls within spec if you want your engine to last. Essentially, what I do here is place a small piece of Plastigage on the journal and then install the connecting rod cap on top using the old bolts. Of course, I will be installing new bolts on final assembly, but these are just fine to use for testing. Before torquing them down, double check that you have the correcting connecting rod cap. When installed, it should look like once piece, even with finger pressure on the cap. The torque specs here are 20 Nm with additional 70 degrees of angle rotation and the 70 degrees of angle rotation again. Once everything is torqued up, the cap can be removed and clearances checked. You are looking for clearance between .025 and 0.76 mm just like on the scale. Since I’m going with aftermarket bearings, I should expect a slightly looser clearance than from factory, but that’s to be expected. If you’d like to learn more about Plastigage, check out the video in the top right corner.

Now that I know the clearance is perfect on this engine, it’s time to do it for real!  I repeat the steps, but this time I’m are not doing it dry and adding some assembly lube to the bearings after cleaning off the Plastigage. With the new bolts in, it’s time to torque it to spec the same as before. We are still doing 20 NM and 70 degrees of rotation, twice.

That’s all it takes to correctly replace the rod bearings on a BMW N55 engine and many other BMW engines of this era. Now, all that’s left to do is to do it 5 more times. As you are checking the clearance on each bearing, you don’t’ want to see too much deviation between the cylinders. They should all be more or less within the same range if done correctly.

Now put the car back together and enjoy another 100 thousand on your BMW. I hope you guys enjoyed this video or at least found it helpful. I put a lot of effort into these videos knowing they won’t be popular, so hitting that like button really does keep me motivated. Anyway, check out the rest of the channel for more DIY video and other car related content and I’ll see you in the next one!

How to Measure Engine Clearances using Plastigage

What is plastigauge.

Hey Guys and welcome back to another video on the SimpleCarGuy Channel. If you have never heard of Plastigauge, you are not alone! Before I started rebuilding this engine, I have never used or even heard of this handy product. What Plastigauge does is measure the clearance between machined parts such as crankshaft and the crankshaft bearings or the crankshaft and the rod bearings. Since the clearance on modern engines is so small, it’s not like you can physically insert anything between the parts. All it really is a thin plastic thread that when crushed by two surfaces can accurately provide the clearance. Before you start, make sure you know the range that your will need for you application as there are many different scales. You can find the specifications for your engine in the workshop manual, technical documentation for the engine or TIS software for your brand of car.

Why use it.

Now that we know what it is, why do we need it? Well, modern engines are built on very, very tight tolerances and clearances that control oil flow to vital parts of the engine, such as the crankshaft. If your bearing clearance is looser than it should be, it will reduce flow resistance and lower the oil pressure and if it’s too tight, you are introducing access heat, which increases wear, which then increase a chance of a spun or welded bearing.

How to use it

Finally, how do you actually use it? Luckily, it is very easy to use but of course there are a couple of things to do before you start. First, clean all of the contacting surfaces so that the result is accurate. Second, make sure you know the correct torque specs for the bolts or screws. The reason that both of these are so important is that if you have debris between the two surfaces or don’t torque correctly, the results will not be accurate. Then, cut a small piece of the Plastigauge that’s about the width of your bearing journal. Place it on top and proceed to install the bedplate or rod cap. On most modern engines, you cannot re-use bolts on the crankshaft or other vital components; however, it IS ok to reuse the bolts for testing purposes when measuring clearances with plastigauge.

How to measure the clearance.

Once you have torqued you bolts to spec, you can release them and remove one of the parts to expose the crushed plastigauge. Now, you can just grab one piece of the packaging that has the scale on it, it can be imperial or metric, depending on how your specifications are provided and place it right on top of the line you see left by the plastigauge. Compare it to the scale to see which one is the closest and that’s the clearance between the two parts. If the clearance is what you are looking for, wipe the ruminants with some break cleaner, lubricate the bearings if needed and do the final assembly. That is all it takes to measure the clearance on crank bearings, rod bearings or any other parts that use this method. Thank you, guys, for watching and if this helped you understand how plastigauge works, hit that like button. If you’d like to see me rebuild a BMW N55 engine, check out the playlist in the description below. I’ll see ya in the next one!

BMW N55 Engine Rebuild Project Part 2 – Piston, Crankshaft and Main Bearings Replacement

Hey guys and welcome back to Part 2 of the BMW N55 Engine Rebuild Project. In this video we install a piston, new main bearings, new crankshaft and seal the bedplate. Since the original engine had chunks the size of my fist, yet still somehow ran, I bought another engine on Facebook marketplace and that’s the engine we are working on today. Check out the playlist to see the teardown video and more info on how I got it. If you’d like to see what the original engine actually sounded like despite having chunks of metal and a hole at the bottom, click the links in the description below and before we start, hit that like button like the piston hit the cylinder head on my engine for the YouTube algorithm and to make me feel a little better for spending so much money on bolts and gaskets!


Now, back to this engine that I got for cheap off of Facebook. In the last video, I disassembled it to see if it was worth saving and decided that it’s actually a rebuildable engine. Since then, I have been ordering parts and cleaning all the parts I could clean. I’ve tried a few different degreasers, but ultimately the regular brake cleaner and even the cheaper AutoZone brake cleaner seem to have been working best. I’ve also learned that using a ScotchBrite pad helped get rid of the tougher, built up stuff and smooth out the contracting surfaces. Even though this looks easy and fast on video, it took hours to do, but I WAS being careful not to damage anything as I’m fairly new at this.

Removing and installing a piston

Since this engine spun the bearing on piston 6, I decided it would be best to replace it for a couple of reasons. The most important reason was that there was damage on the connecting rod where the new rod bearing would go, which of course would not last very long even with a new bearing in pl ace. I was also worried that the connecting rod itself could have been slightly bent, internally damaged or no longer perfectly round and since I have 4 perfectly good pistons from the original engine, I decided to swap one in. I picked the best out of the bunch, gave it a good clean and then went to adjust the piston rings.

Now, it’s a little difficult to see this on camera, but the M-Flex ring is made from 3 different parts. Bearing spring being the middle and two steel band rings that go on top and bottom. The idea is to get the M-flex ring and the two steel bands to be 120 degree apart at the opening or separation point. It’s also important to make sure that the contact point is not arranged over what’s called a pin boss or basically avoid the area where the piston is connected to the connecting rod.

Once you have to bottom ring properly adjusted, you need to also adjust the middle and the top ring to be 120 degree from each other. The instructions on this aren’t super clear, but I went with 120 for the 3 parts of the M-flex ring and then again 120 degree separation between the 3 rings.

Now that I had my piston ready to go, I cleaned up the cylinder wall to make sure it was perfectly clean, oiled it and then oiled the piston as well. I don’t have any fancy tools for installing pistons, but honestly, it was much easier than I expected. I used this $13 tool from amazon and it worked perfectly. It’s a little fiddly, so if you do this a lot, spend more money on something more solid, but for me it worked exactly as I need it to. I oiled up the inside of the tool to make sure nothing got scratched and tightened it around the piston. Inserted the tool with the piston into the cylinder and gently pushed it in with my fingers. You do not want to use any tools here or force it in. The new piston is now installed… woohoo!

Installing Crankshaft

Having actually accomplished SOMETHING, I decided it was time for a little bit more cleaning.. I’ve definitely learned that a big part of engine rebuilding is getting rid of all the old muck and gaskets and all kinds of buildup. If I ever do this again, I might get a parts cleaner or maybe a Dremel with a soft pad or something like that. At least getting it to look new again DOES make you feel like some progress is being done, so that’s a plus.

Now that I felt better about how it looked, I removed the connecting rod bolts and the connecting rod bearing caps on the big end. It’s VERY important that these rod bearing caps do not get mixed up and go to the correct connecting rod when reused or you’ll have another knocking engine very soon. I marked them and put aside until they are needed again when we replace the rod bearings in the next video. The bolts will also be used before the final install for testing, so I’m keeping them for now. Subscribe to the channel so you don’t miss that video! Now that the crankshaft is not held in by anything, it can be simply removed from the engine. Do be careful as it weighs about 50 pounds and you don’t want to drop that on your foot.

I wanted to show you the difference between a good crankshaft and onethat has been abused. Let’s compare the crankshaft from the original engine to the one I’m installing shortly. You can see how much shinier and smoother journals are on the good part. Of course, the old one is not going to waste, it can be resurfaced and used again with oversized bearings.

Back at the engine, I removed all of the old crankshaft bearings, cleaned the area with some ScotchBrite and removed the residue with brake cleaner and a lint free paper towel. We are now ready to install the new stuff!

Installing Main Bearings

WHY am I going with aftermarket main bearings? Well, that’s a very good question with a few answers. First, these seem to have a better reputation with people that have rebuilt their N54 and N55 engines. Second, these King bearings have an improved crankshaft finish for reducing microscopic ferrite peaks if your crankshaft isn’t perfect and since I’m not installing a brand new one, it isn’t perfect. They also have improved oil clearances which should reduce wear on the engine and increase its life. Other than all of those reason, the price was also a factor as these much less expensive compared to OEM.

Installing these is actually fairly simple, put the grooved side in first, squeeze the bearing just a little and push it down with your fingers. They pop in and seat themselves when done correctly. At least they did in my case. The set with a little oil hole goes on the engine block and the solid ones are installed on the bedplate. Of course, I cleaned all surfaces to make sure there was nothing there before installing.

Now that everything is ready, we can temporarily install the crankshaft so that we can check the crankshaft bearing clearance. If it didn’t go in perfectly on the first try, don’t spin it, lift it out a little bit and put it back down where it’s not in the way of anything.

To make sure the bearings have seated correctly and are not over or undersized, it’s important to check the crankshaft bearing radial clearance. For this BMW recommends using plastigauge. I have a full video on how to use plastigauge if you’d like to see the entire process. The basic process is to cut a piece of plastigauge the width of the journal, place it on top of each journal you’d like to test and then install the bedplate back on the engine block.

We then follow the correct sequence to install the bolts and torque them to spec! I left mine for a couple of minutes and then removed the bolts and the bedplate.

Now that I’m confident with the fitment of my new crankshaft, it is time to do the final assembly. Of course, I have cleaned all of the areas again and removed the plastigauge from the crankshaft as well as the bed plate. With all the surfaces clean, I then installed some assembly lube as this will be the only oil between the journals and the bearings when the engine runs for the first time. After the oil pressure is build up, regular oil will go in through the holes in the bearings and lubricate, but we have to protect the engine for those first few rotations. I put some assembly lube on the bedplate bearings as well and even rub a little on the journals directly. This stuff isn’t going to hurt anything and it still much better to the surfaces compared to regular oil.

Since there is no gasket between the bedplate and the engine block, it has to be sealed with a special sealant. The one I got is recommended by BMW and is specified in the service manual. I applied a good bead into the groove as specified.

I really hope you enjoyed this video or at the very least learned something new. If you enjoy this type of content or just like cars, check out the rest of the channel for many more car related videos. Most aren’t nearly as technical. Thank you so much for watching and I’ll see you in part 3 where we install the rod bearings.

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.