N62 Z3 Part 19: Steering Shaft & Power Steering

Soo previously I thought I could maybe use the stock shaft. Which was 100% wrong haha


With the engine mount in place I started looking at where the routing would be. I want it to be as close to the engine mount as possible and as far from the engine mount arm and exhaust manifold as I can get it. Those parts move - the engine mount won't

Below is the perspective from the previous image up to the firewall location

Used some magnets to roughly determine the location of the U-joints and the shaft - this was done in part to see if I could determine the operating angle of the U-joint, to see if I need a double joint, which I miiiight end up needing... it's hard to say right now. The ideal operating angle of these U-joints is 35 degrees or under. The double U-joints go up to 80 degrees. As it is roughly mocked up now, it measures at 42 degrees. The main problem is that as I reduce the angle it will move the shaft towards the engine. I plan on cutting a little bit off the steering rack input shaft, as moving the U-joint location further down the splines will reduce the angle, but I'm not sure it will do so by enough

With some extensions showing shaft routing. It's very tight

Perspective from the middle U-joint looking up to the firewall

Have I mentioned how tight things are?

From the firewall looking down

I also did observe that both engine mount arms will be serviceable with the engine fully installed, which is really great. The driver's side may require removing the alternator- if so I am glad I notched the framerail as long as I did so I can remove that with the engine in place!


Showing the good access to the engine mount arms below

Some other general fitment notes... the X-brace will need to be spaced out to about this point. It's not as much of a drop as it looks. The rear of the X-brace is still just a tad higher than the bottom of the framerails. The front will need small spacers too

A look underneath

I also wanted to check clearance with sunken/worn engine mounts so I installed a worn pair I had on hand... trying to do it like any other BMW, just by raising each side... worked great

Clearance was tight but workable. The "rib" on the oil pan closest to the screen just over the steering rack was the tightest point, I may use my rotary tool to create a little notch where this could potentially rub

Once the original mounts were back in I also ended up raising the driver's side just a tad - it was lower than the other side, doing this also brought the flanges parallel and the bottom and the oil pan level with the x-brace. When the engine mounts are reinforced at some point, I will weld the washer into place onto the bottom of the engine mount

These are the angles of the engine using the swaybar as a reference for zero as I found that to be the best to get a consistent reading of a flat surface relative to the chassis

Engine (and trans...) seem to only be off by .2 degrees which is fairly insignificant, I re-checked with my laser tool and that looked good too so I think I am finally 100% done with trans/engine fitment


Mocking up the shaft... I had previously marked where I thought the U-joint should go so I started there and worked my way outwards

Once again using the power of extensions... I had an idea for a 3D printed contraption but ultimately decided it wasn't needed

Then I re-installed the engine...

Once I had deduced this was the routing, I went ahead and removed the engine again and then measured the extensions to get my rough measurements

I cut the pieces a little long to give me room to adjust a little bit here or a little bit there and then cut the shaft to size. The upper portion remains a collapsible shaft

Currently a ziptie is acting as the support bearing

Then once again installed the engine to see if this would actually fit...

From here it was good, but up top it was really close - basically hitting the headers. I already knew I was going to notch the framerail a bit to fit the upper shaft where I wanted it so I knew fitment would be a little worse than when installed but due to just how tight it is I decided at this point that I will also be notching the headers just a little bit where the clearance issue is just to make sure there aren't issues there down the line. The clearance at the engine mount side of things meanwhile looks fine

Time to start mocking things up. The shaft was hitting the chassis a little bit here, so I cut out the area around it and will eventually weld in a "pocket"

I was maybe a little generous with the cut but I may also adjust this a bit later so the upper bit sits a bit lower

Tack welded the support bearing in place after a lot of test fitting. It is sitting at a bit of an angle here, that was slightly reduced when I disassembled the shaft and screwed the bearing in, shortening the length and moving it "up" the rod, helping to straighten it in the process. I did find that it spins better at a slight angle, so I decided not to have it sit "straight"

This is about where it ended up. I clearanced the framerail with a hammer a little bit to allow the joints to rotate freely in this area