N62 Z3 Part 18: Engine Mounts and Driveshaft

It's so close now I can almost smell the trunkfloor failing


First step of the engine mounts was to make the bracket that bolts to the engine. The alternator bracket made this complicated on the driver's side of the engine. The passenger side is completely flat (like a normal engine mount) so is just a matter of drilling in the right spots

This will be reinforced substantially later but we need a base that mounts flush to the engine before doing too much else. The other side is just flat at the mating surface so it was pretty simple to do


Once the brackets were done I put the engine back in place and aligned it. I was happy to see the transmission tunnel was adequately clearanced, as the transmission not only had visible clearance around the bellhousing but the transmission mounts were no longer being "tugged" forward

After doing more research it ends up it isn't just important the driveshaft "points straight" as the laser alignment tool was determining, but rather what seems to be important is the relationship between the angle of the output flange and the input flange at the diff, as well as the angle of the driveshaft going into and out of the U-joint. So there was quite a lot to it - but now I knew where to take some additional measurements. Using an inclinometer I took the critical measurements and I then adjusted the engine height until the transmission flange was at the correct angle relative to the differential. This put me in a good spot, but I think I may still need to find a way to lower the transmission a little bit more so I might weld a thin but of sheet metal onto the spacers I made

I then aligned the engine laterally and this is where it ended up. The engine is now low enough that the strut brace fits over the intake as well, although its so tight that its rubbing against the intake manifold so will obviously not be used like that

I then double checked things and re-adjusted quite a few times. I think I have it looking pretty good at this point but the laser isn't perfectly centered and this was at the bottom of it's arc

I test fit the x-brace again with the engine at it's now finalized height and it is hitting the lower oil pan on one part, so I will just cut that bar off and reinforce it nearby. It is a very tight fit overall. The lower oil pan is also pretty banged up so I think I may go ahead and replace it before throwing oil in the engine

Oh and on that note I had to remove the steering shaft. It interfered in a very bad way with the exhaust manifold. My original plan was to use the steering shaft from an E46 xi (AWD) model, as I know those routed the steering shaft around the front axles. I thought this would be suitable in my case but after studying it a bit more it simply wasn't going to work


A second idea was to move where the steering column exits the firewall. This was recommended a few times and in an ideal world it is what I would do. However this does add a lot of complications in it's own right just by virtue of, well, hacking the firewall up and moving the column. And it wouldn't even entirely solve the problems on the Z3 chassis, due to the angle of how the frame rail sits back there. All in all it just didn't seem this was the best decision


The solution I was hoping to avoid, making it a two-piece shaft, started to seem inevitable. I priced out what was needed, considered all other options a few more times because holy cow quality steering components are expensive, but ultimately I did bite the bullet and simply buy the parts I needed. Next to the engine, this is the second most expensive single part of the swap so far... but, I didn't want to cheap out with these parts. I also wanted to maintain the stock functionality of the collapsible steering column (an important safety feature) since I plan on driving the car on the street


I mocked up the general layout using some extensions while waiting on parts to arrive and removed the engine to be able to visualize everything a little easier

Then put the engine back in to ensure the orientation would work, I ended up having to adjust it a little bit and all in all the clearance is way closer than I was hoping. But it will clear in this arrangement

From the firewall side, the clearance is good to the engine but I may need a bit more clearance at the chassis. The steering shaft is bolted to the chassis and does not really move much but at the same time, the shaft I am using is a DD shaft so any slight rubbing against the chassis could become a really big nuisance if the chassis is flexing or anything

I then unravelled some of the wiring stuff to see how the OBD port would sit, I just kind of wanted to see it a little more "completed" to be honest, haha

Power steering stuff is a mess right now but I don't think it will be too complicated to figure out. Not a priority either

I also decided I didn't want to stack additional spacers underneath the mount to lower the trans the last little bit, so I will be creating a custom transmission mount after all...


My idea for this was pretty simple and I will use my existing spacers on the sides where the mount bolts to the chassis. I stacked some nuts with various washers to raise the spacers to raise the spacers the right amount above the existing mount and then ground off the little alignment nubs to allow the steel plate to sit flat against the mount

Originally I was planning on welding the new part spanning the middle width to the existing outside pieces but eventually decided to just make new side pieces, this also simplified the production process substantially, as we just had to make a piece that essentially laid flat on top - instead of making a piece that bent "under" the outside pieces. It also allows me to have a jig to make another if I need to for any reason. To make the adjustment was pretty simple, I just had to drop the spacers down by the height of the existing side pieces


This is with the middle section party bent to conform to the mount

Deja vu...

The mount finished, whew! It was pretty simple all things said and done but glad it's done now. It was fully bolted in when welding to try to prevent distortion, I just wanted to take a bit of a work in progress picture as I knew it was missing some of those

In hindsight, I should have drilled the center trans mount holes a little differently. The transmission sits on these at an angle (as you can clearly see) so the effect of this is that as I stacked the plate on top to make the custom mount the holes on the top plate were moved inwards slightly. It wasn't a big deal, just filed them outwards on both sides an even amount


Installed! It's funny, I keep thinking back to how I thought the stock transmission mount would work... I want to go back in time and call myself a freaking pendejo

Great news though is the alignment is now excellent. This is with the rear shaft angled exactly as it should be in operation. It's pretty much a straight shot from the trans back to the driveshaft now

Even got a video...

Awesome! Now I can finally move on from the freaking transmission mount... that became such a big hassle. Next I need to measure the adjustments needed on the shifter carrier so I can get that welded up and then the engine will come back out to work on the steering shaft and then back in to do the engine mounts haha


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