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BMW N54 Cylinder Head Upgrade – Part 1

Posted on 25 June 2012

I still just can’t get enough of the N54 even after 4 years with this car. It sucked not having seen the end of the E92Fan N54 engine build on e90post from a year or two ago. I truly enjoyed everything he was doing but we were never updated on what happened with the engine/car and how it ran after the build for reasons discussed before (owner was too busy getting his restaurant business to work out).

A couple days ago I decided to dive into the incredible N54 jewel under the hood of every 335 and see what this unbreakable beast is all about with my own two eyes, live, after 125,000km of beating, of which the last 40,000km were with RB turbos with the procede, jb4, cobb, combinations of tunes, over 100 gallons of methanol/water/washer fluid, race gas, 4 clutches (stock, cm, act, hpf now), 4 sets of plugs, injector and HPFP recall, year long cylinder 5 misfires, earlier smoking issues, and most of all: oil consumption that was having me add 1L of oil every 1500km (without any noticeable major smoke) and apparent traces of coolant that were found in the Used Oil Analysis reports by Blackstone Labs posted on here in the past while. These traces of coolant had me thinking my head gasket may have a tiny crack in it but I was very doubtful and contributed it to either meth/water injection or oil/coolant mixing elsewhere where they were in close proximity.

Now, this car was DRIVEN! This motor has seen over 150 dragstrip passes. It has seen literally hundreds of 3rd, 4th gear pulls, close to 200 dyno pulls, at least 50-60 60-130mph runs, countless datalogs. Its looked the devil in the face, SPIT in between its horns and came right back up

To make the long story short, engine is shockingly CLEAN. Truly pristine condition everywhere. We started by dropping the turbos. Then down came the oil pan. Then, valve cover. No oil sludge anywhere from the timing chain to the cam bearings to the under side of the valve cover. Clean!

Then came the vanos and timing sprockets and timing chain. Out came both the cams. Looking at them made me think I was looking at something that was literally just off the machine shop floor. I couldn’t believe how smooth everything was still after 125,000km of daily hard driving and abuse.

Next up was removing the head. It came off without a fight. Head gasket, a 3 piece multi layer design, perfect. Not a single issue, I could almost put it right back in of course not but I was just pleasantly surprised as I had tiny doubts about it.

Now come the pistons and this just took my breath away. Every single piston had literally no heavy carbon deposits on it after this much time. The piston tops were basically just darker but again, clean! No visible damage anywhere. Cylinder walls had absolutely no grooves or damage of any kind. To the touch they were as if I was touching bottom of a smooth porcelain dinner plate.

The bottoms of intake and exhaust valves on the front cylinders did have a bit of carbon buildup. Cylinder 2 did have a leaky fuel injector that was fixed under warranty a long time ago and may have contributed to it. But this is also nothing major at all. However, it might explain why I was getting cyl2 and cyl5 to act up sometimes with timing corrections while other cylinders were quiet.

The ONLY noticeable issue, if I can call it that which I found, was that the injector 6 looks to have not been sealing properly. When we took it out and had a look inside the injector holes, injector 6 hole had some discolouration coming down the hole. This can be indicative that cyl6 didn’t have full compression for some time and was robbing the engine of some power.

But that’s it folks. I am pleasantly surprised with the outcome. Here’s some pics I could capture as we were pulling things off last night. They’re off my Galaxy Nexus phone so don’t mind the quality. Phone died just before we lifted the head off so more pics of the bottom of the head, head gasket and pistons will come shortly.

If anyone would like to see closeups of anything, measurements of anything, let me know. Head is off to the machine shop to see what it flows stock and what can be done to enhance its performance further.








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