N52 engine mounting (Z4 arms)

[Striker01]

Maybe the upside-down hydraulic mount hack? (forgot who invented it...)

It moves the engine back 1/2" or so as well.

Which mounts are you referring to?

[adam.nonis]

Hi all,

I have been searching for the AKG Motorsport poly mounts, but they seem out of stock and on backorder everywhere.
Are there any alternatives? I would rather not use the aluminium version of the AKG mounts.

I'm running the Garagistic 24V swap mounts. Stiffer than I wanted, but they're fine for now. Doesn't seem too difficult to swap later.


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[Striker01]

I ordered e46 engine and transmission mounts. I forgot about that Castro trick until Steve reminded me of that video. The AKG work fine but something a little softer will be nice, especially if it moves the engine back a bit, my coolant crossover pipe rubs on the radiator. Just wonder if I'll have to do any adjusting on the exhaust I just finished.

[hoveringuy]

I ordered e46 engine and transmission mounts. I forgot about that Castro trick until Steve reminded me of that video. The AKG work fine but something a little softer will be nice, especially if it moves the engine back a bit, my coolant crossover pipe rubs on the radiator. Just wonder if I'll have to do any adjusting on the exhaust I just finished.

I originally had the hydraulic mounts before we knew any better and had fabbed a custom subframe to fit them (they're too wide at the bottom and will hit the frame rail if you try to mount them with the fat side down...). I will say that they were buttery smooth!
The other issue I had with them being "fat side-down" was that they made access to the steering rack hose fittings tight, so I have high hopes that the "Castro hack" would solve both of those issues.

[Striker01]

I originally had the hydraulic mounts before we knew any better and had fabbed a custom subframe to fit them (they're too wide at the bottom and will hit the frame rail if you try to mount them with the fat side down...). I will say that they were buttery smooth!
The other issue I had with them being "fat side-down" was that they made access to the steering rack hose fittings tight, so I have high hopes that the "Castro hack" would solve both of those issues.

Steering rack hoses won't be an issue for sure now. LOL

[R3vTechnic]

It is a lot easier to make custom mounts than to modify the mount arms. I have not switched to N52 yet (hopefully start swapping this fall) but have been running these DIY motor mounts with an M52.

These mounts were designed with flexibility, adjustability, and prototyping in mind. Using a combination of 3D printing and cast urethane, I 3d print them first to allow for precise fitment and testing before final casting.

Key Features:

• Shared Plate Design – Top and bottom plates are interchangeable from left to right, simplifying production and reducing cost, all metal plates can be ordered from Send Cut Send.
• Interlocking Internals - Internal structure fully interlocks with each-other, catastrophic failure / separation should be none to very low.
• 3D Printed Test Fittings – Initial prototypes are printed with a threaded M10 insert hole, allowing a stud to be screwed in for test fitment.
• Precise Positioning – Mounts can be fine-tuned during the test-fit stage, ensuring the engine sits exactly where desired.
• Urethane Casting – Final mounts made from polyurethane, I used SRC Flex-It 70 (70A hardness), cured in a pressure pot to eliminate bubbles.
• Controlled NVH Tuning – The 70A mounts are actually pretty stiff, voids can be intentionally designed into the mold to soften the mounts and reduce noise, vibration, and harshness.
• Engine Position Adjustability – Mounts allow slight (about 15mm) forward/aft engine movement to suit different setups.
• Future Material Options – Other casting compounds may offer longer working time or better vibration control compared to SRC Flex-It 70 (note CAD below is wrong saying 80A).
• I have been running a set of these on my M52 for about 2 years with no problems although I do not get to drive my E30 as much these days, they are on the stiffer side.

[hoveringuy]

It is a lot easier to make custom mounts than to modify the mount arms. I have not switched to N52 yet (hopefully start swapping this fall) but have been running these DIY motor mounts with an M52.[/LIST]

I love the interlocking design of the AKG mounts, this seems to mirror that.

You could also offset these to easily move the motor back another 10mm (there's room!) or use female threads so at least one side has bolts instead of studs.

[R3vTechnic]

I love the interlocking design of the AKG mounts, this seems to mirror that.

You could also offset these to easily move the motor back another 10mm (there's room!) or use female threads so at least one side has bolts instead of studs.

I have never seen the inside of the AKG mounts but it would probably be something similar. It would be easy to move the top plate hole forward or back & tack a nut to the inside to run studs. I have the file that can be modified or ready to be sent to Send Cut Send, do we have a place we are uploading CAD files. I also have an extra set of plates and hardware you can have if you want them.


Cost to make a set of these is under $85 (gets much cheaper if you make more than one set)

Cost breakdown:
Send cut sed metal parts $33 (this is the price when I ordered enough to make two sets $66/2)
Bolts & Hardwar $9
Polyurethane resin $28 (this would be enough to make at least two sets)
3D print PLA $2
Mold release $9 (might not be needed, I have not tested without it, or another filament might work better)

[hoveringuy]

I'll start with THERE IS NOTHING WRONG with the E85 arms and the standard DOHC swap mounts. It fits fine.

That said, there's still room for the motor to move back, probably at least an inch. I took the geometry of the AKG mounts and made the CAD to offset the engine back another 15mm, had them laser cut as temporary "does it fit?" mounts.

It fits!

My driveshaft CSB is still fine, exhaust is still fine, but need to shorten my shift carrier. Otherwise, LOTS more room in front of the engine and the pan sits basically where it was designed to.

I have several options now: I could either make custom arms to replace the E85 arms with the offset built-in, keep the steel mounts, or learn how to cast polyurethane and make my own offset mounts.

Stay-tuned for DIY mount fabrication....




The E85 arms seem thick so I made the temps with bolt-in top instead of stud and nut. The mount goes in much, much easier!



The pan geometry is perfect now.



There's at least 1" of clearance from the oil cooler now and the VANOS solenoids are easily removed. Maybe room for puller fan?



I want to say the back of the engine is about where we've always had DOHC swaps.

[Caperix]

Is there still clearance to remove the valve cover? The extra space in the front is nice, but the valve cover has to come up quite aways to clear the eccentric shaft & the gasket rolls so easily. Keep up the good work

[hoveringuy]

Is there still clearance to remove the valve cover? The extra space in the front is nice, but the valve cover has to come up quite aways to clear the eccentric shaft & the gasket rolls so easily. Keep up the good work

The E30 is ridiculously easy for pulling the valve cover, none of the E90 cowl nonsense. I could push it back another 20mm and it would still be easy.

Here's what I did today because I actually have time!...


This is the internals to the mounts.


The top side gets a nut welded on the bottom of the plate, the bottom gets a locator pin and a stud. The respective sides get bolted to the halves. Each half has 3 degrees of taper for de-molding. I don't expect them to just pop out, but I just printed a set in PLA so I'm fine if I need to destroy the mold.


... and then polyurethane gets mixed and poured through the sprue (I need to give them chimneys...).

AKG uses Shore 70A but I've ordered 60A for my first attempt. Need to get a vacuum pot and also a pressure pot, according to AI.