One other thing we used to do for final assembly on any motor that had machine work was to fill the water jacket/water passage in the heads with shaving cream. This prevents any metal, glass bead, etc from falling into the motor during assembly. Initially fill the motor with water. Then drain after you get it running and fill with anti-freeze.

This is old school stuff. I doubt it will cause a problem with BMW water pumps; but, may be worth asking your buddy.

And yes, I am giving away my age a bit.


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Nuts, me too! This guy has way more skills than me! BMW MacGyver right here!

Guys- the whole reason I bother documenting this stuff is so other people can reproduce the procedures!

Anyway, I wanted to show a few more photos of the sealant injection process. After I failed the first time, I wasted the $60 cartridge of adhesive and had to buy another one from the dealership. But before I was ready for attempt #2, I emptied the first cartridge and filled it with honey because it has a similar viscosity. I then dialed in my technique using honey. Once it was proven, I disassembled the engine and cleaned the honey out.

To make sure I had enough adhesive to fill both sides, I measured the displacement of the piston before & after each injection. Interestingly, each injection used exactly 25% of the cartridge volume. So if you undertake this procedure yourself, know that without wasting material you can safely have one failed attempt.

Anyway, here are photos from the actual injection. The previous photos were honey injection.

I don't wander to the E70 side very much, but this was a fantastic read! Great job!

Wow, I can kiss your hands, great job and a great read. I am in the SF bay area myself, do you do this for business or working on this as a hobby? Would love to get tips from you if you are open to it.

Comparatively I have a minor issue here, have a coolant leak from the radiator :|

Hey guys, to answer a few questions I've missed:
-I'm not doing anything to the cylinder head. It's in perfectly good shape with the exception of the sludge buildup on the springs, which I'm not very worried about. The only risk is worn valve seals which could result in excess oil usage. The problem is, the N55 cylinder head is pretty complex and I'm a bit worried about maintenance-induced failure.
-I didn't actually check crankshaft end play. But because it's a brand-new crank on brand-new bearings I'd be shocked if it were out of spec.

This is just a hobby for me! I only have a 1-car garage so even doing this can be tricky at times. Feel free to PM me or start a thread if you have questions!

Ultimately, I couldn't find a used N55 connecting rod anywhere in the country. Sadly I was forced to buy an OEM set of 6 connecting rods (P/N 11247624615) and the remaining 5 will be sent to eBay. On the plus side, they come balanced as a matched set so I don't have to worry about balancing.

Yesterday I completed bottom end assembly, installed the cylinder head, and power washed the engine.

Pictures of pressure washing. For the oil passageways, I used rubber stoppers purchased from the hardware store. For the intake and exhaust, I used bunched up rags. For other holes I used ziplock bags with zip-ties.

Are you concerned about the piston coating apparently coming off?

Actually that isn't a factory coating; that's burned-on oil from the heat inside the engine. There are coatings on the piston's side skirts, but those stayed on through the cleaning process.