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BMW S54 into S30 Chassis - Build Thread


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Hey everyone, 

So I've been into doing this swap for over a year now, collecting parts along the way, planning, building my engine, test stand, and most recently getting my s54 running. SO i figure it's about time I start a thread that I can post up pictures, and progress as I go.

So it all started back in 2017, when I bought my first Z. It was a white 280z, tan interior and was pretty stock overall. I loved to it and it really got me hooked. I drove it for a while and once I started to get this idea seeded in my head of swapping in a BMW motor, I began to realize, that I had the wrong car to start out with. It was in good shape, had been repainted real nice, but it had been in a front end accident at some point and the front frame rails were a little buckled in front of all of the suspension pickups. Not wanting to deal with that or some of the other things that may have been hiding under the fresh paint, I decided to sell it. In the mean time while selling the white one, another one showed up on craigslist (of course) about 40 minutes from my parents house.  My Dad did me a solid and went to look at the car for me and was able to report that it was in reasonable shape, but not running.

Long story short, I bought that blue car in May 2018 and then stored it in Virginia for almost a year while I finished selling the white 280z and started building my S54 completely fresh and planning out what I wanted to do with the rest of the build.


So that is basically the back story. The next few posts will be for my engine build and the test stand that I build for it.





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Not that it will directly interest too many people here, but my S54 build was pretty in depth and took place over about 8 months. I sourced parts from all over the place, but had the block bored out, decked, and aligned honed on the mains. I managed to find a 30k mile crankshaft that measured out with the micrometer to be completely nominal on every journal (rod and mains) that I had dynamically balanced with the new pistons and rods to within 1gram. Should spin nice and smooth all the way to 8200rpm. Standard cams and a bunch of parts that are known to "bullet proof" these otherwise finicky engines and a nice paint job and I ended up with a very pretty engine if nothing else.


Along the way I had picked up a BMW 5speed transmission out of a 328i for really cheap and decided that would be what I use moving forward. Now that I had the engine and transmission, it was time to connect them up and see if I could get them to function on their own, outside the car. Enter the Engine Test stand side project. 
















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Engine Test Stand... This step probably wasn't entirely necessary, but I did it so that 1) I could get the engine running after an 8 month build process and 2) so that I could work out any of the bugs with the wiring and the computer before trying to integrate it into the car. I wanted to know that this thing actually worked before it made its way into the car.


I bought a new welder and some raw material and went to town. Most, if not all of the accessories I have, will be used once the engine is in the car again, for consistency sake. some of those include:

full suite of custom speedhut gauges that will make their way into the car

Z Car depot 2-pass aluminum radiator

Mishimoto 10-row oil cooler (may make this bigger eventually but this works for now)

Bosch 044 fuel pump

Summit 10 micron inline fuel filter

Aeromotive fuel pressure regulator

ATL Well Cell fuel cell

Kassel Performance tuned MSS54HP ECU set up to run as a standalone engine management


In addition to all of this, I wanted to use the actual front cross-member from the 260z to hold the engine on the test stand. This where some great forum members helped out immensely. Luckily, there are a few more rogue people like me that have put BMW engines into S30s and did some really great work to document how they did it and BMW was nice enough to make the engine pickup points the same on their 6-cylinders for nearly 20 years. RTz actually went through the effort to make engineering drawings of his engine mounts and M3240z documented his build with lots of pictures that have helped in a big way. I can't thank those guys enough just for helping me get to this point.


Once this thing was done being built and everything mounted up, wired in and ready to go, it finally started for the first time on July 31st, 2019. She ran great with almost no issues. I plan to do a very basic "break in" while it's on the stand and go through a do a full leak check. Once it's installed in the car, I will do the actual break in procedure that my machine shop recommended. 


Next post will be about the car...















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With the engine built, and the test stand operational, let's take a look at the car itself.

It's a 74 260z, VIN in the high 28,000 range. When I bought it, it didn't run which didn't matter so much since an engine swap was the prime directive. 

The body was in really good shape from every indication I could see. Frame was straight, floors not rotted out (depsite being a little dented from someone who didn't know where to put the jack), battery tray completely mint. The only area of concern I could find was along the rear valence in the sheet metal behind the rear bumper. But it was isolated to that area and seems to stop well below the license plate. Other than some minor hail damage, the sheet metal is as good as i could expect for what I paid.


Like I mentioned in my first post, after I bought the car, I stored it for nearly a year in Virginia while I built the engine. (I live in Michigan). Once I finally had the car in Michigan, I made short order of completely stripping it of every part I could find that had a fastener. Now the car is sitting on jack stands in my garage. That is pretty much where the car sits for now.















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Other projects I've completed in the mean time: 

Rear differential build:

               - 83' 280zx R200

               - 3.90 ring and pinion

               - Mfactory HLSD 

               - new bearings all around and a fresh coat (several actually) of paint

CV axle build

               - '84 300zxt CV shafts

               - 4340 shorter axle shafts from White Head Performance

               - 27 spline companion flanges from White Head Performance 

               - stock 27 spline outer stub axles that came with the car


Can't say these next ones are projects, but they are parts waiting in the wings until I go to put this whole thing back together.

Full T3 rear suspension

Arizona Zcar front brake kit

IMPUL steering wheel

Recaro Profi SPG seats

Vintage Dashes replacement dash board
















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Looks good, it looks like your engine is already together so it may be something for latter, Lang racing offers a widening service for the rod bearings that is supposed to eliminate the rod bearings wear these engines experience.  Even after 2 recalls most cars run hard still wear out the rod bearings around 60k.

It should be a nice engine for the lighter e30.

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4 hours ago, grannyknot said:

Fantastic, the S54 is certainly the best straight six BMW ever made.  Are you really going to run your trumpets like that, sucking road dust into your pristine cylinders?  It would sound glorious though.

The trumpets will have their own individual filter setup before it runs on the road. Just haven't gotten them yet.


3 hours ago, caperix said:

Looks good, it looks like your engine is already together so it may be something for latter, Lang racing offers a widening service for the rod bearings that is supposed to eliminate the rod bearings wear these engines experience.  Even after 2 recalls most cars run hard still wear out the rod bearings around 60k.

It should be a nice engine for the lighter e30.

As far as the bearing wear issue, I have heard of Lang's service and I have also heard mixed things about that process. I decided to just use the best OE crank I could find and if I need to service the bearings every 60k miles, that's not too bad considering that is going to take quite some time to rack up that many miles.


And yup, aiming for 340hp and 2500lb. Should be more than enough while still being balanced.


Today was about seats and getting the glass out. The Recaros are going to fit great. I just need to get them lower down in the car. I have the side mounts and sliders coming this week. 


I got all of the glass out of the body with no drama, except that I cracked the windshield. Any specific places known to have quality replacements? Seems like $150 is the going rate for one from the normal Z stores.






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19 hours ago, carbuilder723 said:


I got all of the glass out of the body with no drama, except that I cracked the windshield. Any specific places known to have quality replacements? Seems like $150 is the going rate for one from the normal Z stores.

I've heard a few times over the years that the new windshield glass is a slightly different shape around the corners and can cause some leaks if not sealed up properly, personally I would pick up an old one.

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  • 2 weeks later...

This thread: "https://forums.hybridz.org/topic/59086-enginetrans-weights-definitive/" has some excellent information, but also leaves me a bit stumped.


It gives 363 lbs for the long-block L24 dressed with intake/exhaust bits.  A later post in the same thread gives 589 pounds for a complete L28, transmission and clutch/flywheel parts.  Maybe I’m compareing apples to oranges, but are the flywheel/clutch transmission 200+ pounds?  A later posting gives 291 pounds for the Datsun L16.  Again, maybe apples to oranges, but if a 4-cyliner is 291 pounds, would it be reasonable for a six-cylinder from the same family (50 % larger?) to be only a few pounds more?


And finally, in the same thread, the S52 (American version of E36 M3, after the stroke was increased for the 1996 model-year) is reported as weighing 406 pounds for the long-block.


Not to impute any of the participants in the above-cited thread, but the spread in weights is, to me, counterintuitive.  The inline-6s should (I think) be heavier.  Having another data point, now for the S54, would be very welcome comparison with the S52!

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Here we go, the crane scale is accurate, the engine leveler is 10lbs so subtract that from the totals.

S54 with partial headers, throttle bodies, damper and some coolant pipes. No stater or Alt. 341lbs

With flywheel and clutch pack, 380lbs

6MT transmission , 105lbs.  Total 485lbs.

L28 and flywheel/clutch pack plus 5spd transmission 425lbs.









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So this last week was about getting the shell up onto a frame so that I could roll it around the garage and driveway. 

Also, a friend and I went to town on removing all of the sound deadening from the floor pans. Dry ice was our friend here, but even the trans tunnel material was still a total pain.

Then I started to cut into the some of the areas where I was suspicious about with respect to rust... let's just say, I was right to be suspicious. Looking up into the dog leg cavities, the metal looks in really good shape, but the bottom skin and secondary layer will definitely need some pieces replaced. The rear valence (as suspected) was also full of bondo so I'm likely going to try to just replace this entire panel.







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So I went to poking a few more holes last night and good thing... found a few more areas that will need patched up. I also got the rain hat removed from the inner cowl and found that I will definitely need to do some work on the passenger side cowl, including the air intake tunnel/tube.



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Progress is being made, although a bit slow. Big news though... I test fit the engine for the first time and, surprisingly it fit (sort of).The first test fit was with the front sub-frame completely unmodified. Just the engine adapters sitting on the BMW isolators sitting on the Datsun sub-frame.





In this configuration, there was an interference at the back of the engine with the hood latch bracket, and with the exhaust at the right hand frame rail. Surprisingly though, the oil pan to Left side TC rod mount seemed to be reasonable enough with out any modification. The previous swaps I've seen with this engine had required the oil pan to be trimmed in this area, but (for the moment) it looks like I won't need to do that. Also in this configuration, the front of the engine sits very high... high enough that I think it would be a problem with the hood fitting. IMG_20190830_215413.thumb.jpg.e6b6604ced4bb79da75504d772428273.jpg








So... the next thought was to take the front of the engine down a bit, so I cut about 1.5 inch off of each standoff on the front sub-frame. I haven't test fit this in the car yet, but it put the front of the oil pan approx 2 inches closer to the cross member in the front. I figure this has a few benefits including lowering the CoG, clearing the hood and possibly solving the interference at the hood latch. We'll have to see once I refit the engine with the modified sub-frame in the car.







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While not the exact same engine, Ron put 1/2" spacers under the front crossmember for his S52 powered Z. They don't screw with suspension geometry enough to really matter (you could always correct it if you're crazy). You can also buy them from Jags that run for pretty cheap.





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