N52>e30 Build Thread for the Sophisticated Gentleman

[nando]

What color is your car? Duplicolor silver wheel paint is *really* close to sterling silver. It's maybe a half shade darker, but it would probably match the cosmoline stained paint of your engine bay pretty well.

[hubcapboy]

I wanted to get a few components of the brakes and fuel figured out before the engine was in the way. Here you can see my bracket for an S54 fuel pressure regulator and a brake proportioning valve plumbed in the location of the old rear circuit delay valve. I used the mount location from the carbon vapor cartridge for my FPR... so I'm going to have to find a new location for that, but this meant I didn't have to weld a new bracket for the FPR and I can move it later if I absolutely need to:



Here's the e30 brake pedal linkage bzzzzz'd onto the end of the shaft of a bosch brake booster from a 2016 Tesla model S at the correct length (about 5"?). I expect this brake booster to work great but will reserve judgement until the car is moving. The reality is it's the only booster I can find that gives me room to retain the N52's 3-stage intake manifold. In order to get the brake circuit connections on the correct side of the master cylinder, I needed to track down the master from a right hand drive Tesla.



Yea... it's not pretty. This are my original brake lines bent around to fit the new location via some brass adapters I found from Brake Hoses Unlimited, they call it a "Brake Line Thread Adapter, Male M12 x 1 Inverted, Female M10 x 1 Bubble"



Looks like it belongs there! There are no changes needed to the firewall bolt pattern, I just have the booster section rotated 180 degrees to move the control box away from the engine (orientation for this doesn't matter):



There's a few more things to clean up before the engine goes in... but it isn't much. I have at least some cleanup and re-mounting of the rack, fitting the new power steering hoses (why not now) and some rivnuts to place for that coolant crossover pipe.

[2mAn]

Awesome updates.

In regards to the radiator mounting, would a late model be better, or is it a moot point either way due to the radiator used?

[hubcapboy]

Here's the old (now blind) round hole next to our new nut clearance, with the bottom subframe reinforcement trimmed back for socket clearance:



I secured the plate through the common hole:



and started thinking about tacking them in like this:




I lost a perfect rotation reference when I opened the slot for the nut clearance... so these now need to be located by aligning the three holes across both sides. It's pretty paranoid to worry about this, because the hole we're rotating around is so close to the center that it's really not moving much... but a straight edge between the mount plates aligning with the six holes will get them in the right spot.



Bzzzzzzzzzz then some paint:

[hubcapboy]

If anyone reading is hoping to do this swap and they bought parts from me (if I ever sell them to anyone), this is where you need to pay very careful attention.

These are the two subframes I have at hand. The top photo came out of an '88, and the bottom photo is from my '87. There's a slot and a hole for the m20 motor mounts, but *YESTERDAY* I learned that the web between the slot and the hole is a different width on these two frames.

Originally, when I designed the adapters, I didn't account for two things: 1. I didn't know about this web difference, and my reference point was the inside edge of the slot and 2. I forgot that my '87 subframe had been reinforced with a doubler plate inside and was thicker than the one on my mockup car. If there's conflicting information on how this geometry works from any previous posts... this is why.

Here's the subframe from the '88 (maybe it's actually an '88, maybe not):



Here's the subframe from the '87 (Maybe it's an '87, maybe not):



That extra 1/8" of web on each side is unsettling, but fortunately the distance between the two round holes (which for the e30 are what locate the mounts) are the same. So our new method of locating these plates is using that hole. Good thing I put it there I guess? The second problem is the reinforced subframe. This adapter plate is to adapt an e46 hydraulic motor mount to our e30 chassis:



It's thick because we need to lift the motor mount up to clear the frame rail, and it fits on the motor mount like this:



The hole on the left is for the motor mount stud, the middle hole aligns with the round hole in the e30 subframe, and the hole on the right is only there for the nub on the motor mount to stop it from rotating. When I was using these plates in the mockup car, I had just enough thread engagement to feel ok about the nut... but it wasn't great. I was planning on tacking this plate in place to fix it for rotation (using a bolt through the common hole) and just using it as a spacer, but with any reinforcement in the subframe there wasn't enough to feel good about it. luckily, this plate already had to be thick to space the mount up, so it's plenty strong enough to *be* the reinforcement, and the nut can snug up to the bottom of it after making some clearance:



Here's what your poor subframe looks like after doing that. Make sure you leave enough of the round hole to locate a bolt, but the slot does need to be opened up to connect with it. It needs to be large enough to fit the flanged nut for the motor mount, which is 22mm OD. I did this using a step drill roughly in the slot and then a die grinder to open it up a little further. If you have the "lower" reinforcement piece on, you're going to end up drilling into that too, but it also needs to be opened up to allow the nut to be tightened, so just keep going with the step drill.

[hubcapboy]

There's a few things to note here. The first is the ugly paint on the frame rail. Sorry. Next, This is an early car, so there were tabs along the bottom of the radiator core to support the radiator and they've all been trimmed off (the little rectangles) to make room for a coolant crossover designed by hoveringuy that I don't understand fully yet. The last is that I don't have any way of supporting a radiator any more.



These are brackets that I *think* will reproduce the radiator mounts from a late-model e30, which are common geometry through the e36 and z3. I didn't document these very well because there's a ton of better ways of doing this... the easiest being ordering the original pieces to weld in, but I was poorly prepared for that. I also don't know if I'll ever be able to mount a different radiator because I located these off my ebay radiator... so I hope it's close.



The idea is that they sit here:



And here:



And using a late e30 radiator clamp for the top and some foam tape against the core, the rad is held in place.



I'm using a dual-core radiator with a built-in pressure tank on the drivers side... This is a "performance" upgrade from some 4 cyl z3's and I think some european 4 cyl e36's. Another early car issue is that I have my pressure tank on the wrong side for the new engine, and although I have a late tank and the brackets this seemed like just as good of an option (if it doesn't interfere with the engine... which I hope it wont...) The area is smaller than a 6 cyl radiator, but it's double core... and the core that is there is better aligned with where the fan will be (circles don't inscribe very well into a rectangle).

[hubcapboy]

My original goal for this swap was to do it without ruining the car... as far as the chassis knew, there hadn't been a swap. I bent that rule for a few things, the first being the clearances for the headers. The n52 manifolds that come on the North American cars bring the front and rear banks together very quickly to be picked up by the first O2 sensor, and the catalyst is pushed up against the side of the engine so it gets heat as quickly as possible. There are N52 shorty headers from the factory on some European models, but I wasn't able to source them. There are a few aftermarket header designs for the e90, but they're all designed around tight tolerances in the e90 chassis... and my (also tight) tolerances are different. Most (all) of these BMW 6's have common bore spacings, so a $50 set of factory manifolds from an s54 adapted to new manifold flanges is what we settled on. After mocking them up, one of the primaries was too close to the frame rail for comfort. This part of the frame rail is in front of the shock tower and is already dimpled to act as a crumple zone, so cutting into it wasn't a huge concern.



The idea here is to trim out some of the inside rail and replace it with piece of a sweep from an exhaust 90. This is a heavy gauge stainless elbow:



No going back now... This location was determined measurements on my mock-up car, then hoveringuy making an impulsive decision, then my re-measuring his work:



It seemed easier to trim the rail to the profile of the elbow, then mark and trim the elbow back to what I needed. Oh look! there's the heater frantically trying to cure the soundproofing!



Here it is looking its worst... This got some high heat paint that's a poor match for the engine bay and some seam sealer that you'll see in later photos:

[hubcapboy]

First step of underhood prep was to figure out what I was going to do about the huge rubber blanket that mounts to the firewall on the e30. Mine was falling apart into chunks and was mostly just sitting on the bell housing, and although they're still available, it didn't seem like a great solution. I didn't find it straightforward to find a product that was really supposed to work here, so I went with a combination of 3M rubberized undercoating and a sticky heat shield:



Here's what 3 x 16 oz cans of rubber looks like on the firewall. I was feeling pretty good about it at this point. I've used this before and it set up to a durable finish in less than an hour.



Here's what it looked like after I stripped the masking off and started to panic because the top 1/8" had set up.... and looked like a pretty good vapor barrier... and it was plenty gooey underneath...



Fortunately... after a week with a heater sitting under the hood it was ready for the next step. This is HP Sticky Shield, which is an aluminum foil with a thin fiberglass batt and an adhesive on the back. The seams are another product from HP, which is a thinner aluminum and adhesive with woven glass fiber tape in between instead of the batt. The normal batt shield is pretty tricky... it's about as "strong" as regular pink fiberglass wall insulation, so it's super, super easy to pull the adhesive away from the aluminum. If you don't reinforce it and capture the edges with the tape... I don't see this lasting very long:



This treatment went most of the way back to the shifter boot, with all the little HVAC drains poking through and all of the original studs and washers from the rubber heat shield re-used as a backup to the adhesive:



I don't know if this will be as effective for heat OR noise as the original rubber to be honest...

[2mAn]

I know you wanted the other thread cleaned up, but thats neither sophisticated nor the gentlemans way. This thread is the Sophisticated Gentleman way.

+1 Subscriber

[Victell]

Enthusiastic sub

[TobyB]

Sophisticated Gentleman

Obviously, you've completely missed your market, and I'm completely ignoring you as I have an M54B30 ready to go into mine

he says, following this thread rather closely.

t
in for lots of deets.

[hubcapboy]

I told you I was going to forget something: fuel pressure regulator. I have to get a bracket built for that before the big day.

[Bored]

N52B30 is definitely what I'd consider a perfect engine for the E30. 6 pots, all in a nice straight line, tidy horsepower, dandy weight, and a very compelling design.

[nando]

Just an aside - an "S" variant of the N52was planned, but ultimately cancelled due to the push towards turbos. If you study the N52 head you'll realize the design is based heavily on the S54 (even CNC machines intake ports).

The rumor is the M-team engineers really wanted to stick to N/A designs, but were overruled by upper management. Consequently, many of those engineers quit and went to work elsewhere - notably, Hyundai. It's not exactly a world class secret that modern M cars have lost the plot.. whether they're faster on paper or not.

Also, N54 swaps are just as doable. I'm not aware of any successful ones that didn't involve swapping all of the body electronics as well, except one in an E36, that I helped with. Personally, I don't really care about the N54 and turbo dick measuring contests - an N52 should easily be capable of 300hp, which is plenty in an E30 (especially considering the weight). But if turbo is your thing, I won't judge.. ;)

[moatilliatta]

Stoked.