Aligning an engine swap and building engine mounts

Hi all! Firstly, thank you to Nigel for setting up this course. I'm looking forward to making my way through the videos.

I wanted to ask a few details about performing an engine swap. I'm in the process of fitting an OM605 Mercedes Diesel engine into a BMW E36 Touring. The engine and gearbox are currently in the engine bay, and it looks like it's going to fit relatively smoothly.

My questions are;

How do I go about aligning the engine in the vehicle? Specifically, making sure it's central in the engine bay, at the right angle and aligning it to the two-piece propshaft.

I've used a laser level to find the centre of the vehicle, and I've aligned the centre of the crankshaft to this datum. I've also tilted the engine to the same angle it was fitted in the Mercedes. At this point, all is looking well. Where I'm struggling is how to align the gearbox output shaft with the spline on the rear part of the two-piece prop, just before the central bearing. I've read that these need to be perfectly aligned. Unfortunately, I've not got access to the alignment ratio from the Mercedes, nor the BMW. So I'm kind of blowing in the wind here.

What's the best way to create engine mounts? I've created two plates in 5mm steel which bolt to the engine block. I've also created two plates which bolt to the rubber engine mounts. Essentially, I just need to connect the two. I've attached some pictures to show my progress.

Thanks in advance.

Ben

Hi Ben, great project, firstly utilising the two piece prop is a great way to simplify the process of a swap, one piece propshafts tend to have some balancing issues and can be tricky to get right. I’m not familiar with that type of prop shaft though, can you upload a photo? Most will have a uni flex joint in the center and can deal with some misalignment. As for the engine mounts I would do a pair that look like the uploaded photo. Make a plate that bolts to the engine mount and then use some paper, cardboard or plastic to create a template, Mark that back to the steel and once tacked in place gusset for strength.

Regarding the 'tilt', if the engine is inlined left/right, it isn't unusual for the crankshaft centre line to be offset a little to the side, to better balance the engine in the vehicle. If it is in the fore-aft direction, the 'correct' angle may not be the same for the BMW chassis - the normal practice is to have the differential input flange at the same angle as the gearbox output shaft, which will be the same as the engine.

This is because the usual "Hooke" or 'cross' type of universal joint will vary the in-out rotation speeds as the angle increases and correctly angling and phasing will minimise driveline vibrations However, there is a complication in that you have a 2 piece propelor shaft and haven't told us what the various joint types are - it is possible to incorporate joints which alter that 'usual' driveshaft angle requirement.

If you can give more information on it, especially if you need to adapt one front to the other rear section, it would help a lot. Oh, on that, IIRC, there have been some problems with BMW flexible couplings, so you may wish to check on those as it may affect your design decisions?