N52 Swap Discussion

[hoveringuy]

Here's one of the big reasons whey everyone complains about radiator clearance on the N52. This is the coolant bypass hose, it goes from the "mickey" fitting near the regular radiator outflow to the "closed" side of the thermostat. The radiator connects to the "open" side. When the thermostat is cold, the radiator flow is blocked and the only flow is through this hose (and some through the heater core) to keep water circulating through the engine when it's cold. Once the coolant gets hot enough, the thermostat opens and it's a mix of radiator flow and bypass from this hose.

It sticks out so far because it needs to clear the serpentine belt.



I don't have AC, so I don't need the most of the serpentine belt, I'm only driving the alternator and power steering on the drivers side. Since there's a cheaply available aluminum fitting for the water pipe "mickey" (the stock plastic fitting dissolves after XX miles), my task has been to fab an aluminum hardline that could run closer to the block. I've made my second prototype and it checks all the boxes. Next step is to have a number of aluminum tubes bent to reduce it to one weld at the fitting.

Clearance to the radiator is now basically limited to the profile of the cylinder head and the damper pulley. A 50mm radiator should be no problem, let along stock 33mm.


I haven't decided if I want to use the second mounting boss yet. It's where the plastic hose-holder was attached.

[hoveringuy]

I haven't had the car driving for a week because after proving that it all works, I've taken some things apart to make improvements and move toward my "forever" configuration. Radiator and the front of the engine is the focus, starting with installing a modified oil filter housing with an M14 bung for the e30 cluster sensor.

The cross-under tube which was previously EMT is now professionally mandrel-bent 7/8" stainless.

You will also notice the clearance to the radiator, another goal is to fabricate a hardline for the coolant bypass hose that's normally close to the radiator and, finally, look at using an N54 serpentine tensioner.

[hoveringuy]

Yes, it does. Both coolant and oil temperature based.

The 330i doesn't use an oil cooler, i don't think the Z4 did either. It was mainly the bigger cars - X5 and 5 series. The X5 was rated for towing 6,000lbs.

I can confirm the coolant failsafe. I popped a radiator hose that wasn't tightened enough. There was a puff of steam and the engine went to reduced power.

Tightened, refilled and was on my way.

[nando]

Yes, it does. Both coolant and oil temperature based.

The 330i doesn't use an oil cooler, i don't think the Z4 did either. It was mainly the bigger cars - X5 and 5 series. The X5 was rated for towing 6,000lbs.

[Caperix]

Does the Msv70 have a failsafe mode once oil temp gets to high? All the high output n52s use an oil cooler, granted an e30 is lighter than even a 1 series.

[nando]

Most N52s didn't have oil coolers from the factory. I'm sure you can fit one (there's a filter housing with one built in that should be a slam dunk), but IMO, it's not worth the added complexity, the N52 really doesn't need it.

I'm basically looking at deleting both the oil cooler and power steering with my build. Less mess, less maintenance, less weight. :)

[Caperix]

As long as it cools properly with just a pusher there isn't much reason to redesign everything. Is there room to add the oil cooler to the oil filter housing if needed, either the larger water cooled cooler or the smaller air cooled thermostat adapter from a n54/55?

[hubcapboy]

Engine position is page 15:

https://www.r3vlimited.com/board/forum/e30-technical-forums/24v-engine-swaps/385417-n52-swap-discussion/page15

There’s a good shot there of how much room I had from the head to the firewall. If we have a real lessons learned I’ll go back and link forward to here.

[hubcapboy]

Engine position ended up being determined by 1.5 things that didn’t matter to Steve, but did matter to me.

I might have a chance to check where the notes are longitudinally relative to the M20 when I pull mine.

The interferences I remember running into were the heater core stubs to the intake (I’m using the three stage, Steve is using the N54 which is MUCH smaller and clears these laterally) and the transmission tunnel. I’m sure there’s a way to easily redirect these heater stubs, but the trans tunnel problem led me to not try.

I have the 330i transmission which is longer and I believe larger. I think this explains why Steve has room to go back when I didn’t think I did. If I’d shifted the engine back it would have had to go down, and the subframe would have conflicted with the block.

[hoveringuy]

Looks good, is it just the angle of the photo or is the engine very close to the radiator?

I think the engine is identical in distance to the radiator as my M54 was, the issue with the N52 is that the coolant bypass hose runs in front of the engine and it gets within 8mm of the radiator. To the point where I'm not sure if I could run anything thicker than the OEM 33mm core in an all-aluminum radiator, for instance.

Meanwhile, at the back of the engine there's miles of clearance...

The positioning was predicated on the shifter being centered, naturally, and my shifter is maybe 5mm forward of the middle so there's future opportunity for the motor to slide back just a hair, probably 1cm.

It looks much better from the bottom, where I have 2" clearance between the damper and the radiator core.

[Caperix]

Looks good, is it just the angle of the photo or is the engine very close to the radiator?

[hubcapboy]

It's from all the lightness we added

[nando]

Nice! Also, does it have a lift kit? :p

[hubcapboy]

Hey look what showed up at my house the other day tootin' it's own horn:

[hoveringuy]

Throttle pedal, done.

I'm using the Z4 manual pedal which is considerably more svelte than an E90 pedal or anything else. The usual route is to use an E46 pedal and make a bracket and some epoxy, but I think this worked great.

The pedal (P/N 35426853176) is meant to be mounted with an allen head bolt through the baseplate, so I welded an M6 nut in front of the e30 bracket for it.

The rear has a cavity where a catch plate grabs the top of the pedal and secures it from lateral movement as well as rocking forward. Conveniently, the e30 bolt hole sits exactly in that pocket so it was a quick matter to fabricate a plate. It slides down onto the plate and is then bolted at the bottom.

Rock solid!






Comparison of the two pedal styles. The Z4 style (left) is over 1/2 lbs lighter and the plunger is more robust. BOTH of them have the recess in the back for the catch tab. They work the same, but the plug is different between them.