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Discussion Starter #1
Hello from Greece!

A few months ago I found in a junkyard an old 540 E34. My daily drive is a 525 E34 but I always wanted to upgrade to something larger, so I purchased the 540. Unfortunately, it has no papers, so it is impossible to issue plates for this car. Anyway my plan is to fit all the equipment from the 540 into my white Alpine III 525.

There is a problem however. As you may have already guessed the 540 has an automatic transmission, which I hate it since I want to have the absolute control of the gears.

There are no many options regarding manual transmissions for the big V8, so I found and purchased a 6-speed manual gearbox from a 540 E39 for which as I have been told that it fits perfectly with the M60B40 engine, am I right? I also bought an LSD from a M5 E34 but this is another story!

My problem is that I cannot find a flywheel. I also don’t know which one should fit? Am I looking for a flywheel from a manual 540 E34 or from a manual 540 E39? Are the same? Here in Greece manual 540s are extremely rare, as snow in Sahara! I would like to find a cheap used flywheel but I can’t! The local BMW dealership asks a small fortune (about 1600 Euros) for a new one, so my only solution is to find a used one.

Can anyone help me with this project? First of all, I need to know the exact type of the flywheel which I need for the M60B40 engine and the 6-speed gearbox from the 540 E39.

Many thanks in advance and I look forward for your replies!
 

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Sorry I don't have experience with mix-matching various parts from various years. In my mind it would be safer for parts matching to use an e39 V8 flywheel, clutch disc & pressure plate while using an E39 trans. I do recall some sort of clutch disc diameter differences between the E34 & e39 540's, I think the E39 had a smaller disc despite having a larger displacement M62 engine.

The E39 flywheel has the crank sensor reluctor ring and the crank sensor in the bell housing? The E34 540/M60 has a front harmonic damper mount crank sensor and would be the one to use in the swap with the E34 404 or 484 DME. But if there are any machining differences in the trans bell housing or input shaft/spline depth to compensate for the reluctor ring I'd want to have the proper depth flywheel and clutch too.

Again, this is my speculation and not first hand experience.

The E34 M5 differential with 3.91 gears is going to be alot of fun, but first gear will disappear very quickly during acceleration and 6th gear high speed will have some fairly high cruise revs.
 

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Discussion Starter #3
After asking a lot of mechanics with previous experience in BMW engine swaps I learned that the flywheel and the clutch disk from an 850CSi will 99% fit well in the M60B40 engine. Can anyone verify this statement?

The LSD from the M5 E34 has a ratio of 3.45 not a 3.91. Now, if I put it as it is then I will have a very good acceleration but a very limited top speed (my calculation indicate a top speed of about 254 km/h). My plan is to fit the pinion of the M5 LSD into the diff of the 540 thus keeping the ratio constant at 2.93. Then the top speed will be above 280 km/h which is equal (or even higher) to a real M5 E34! Note that the extremely rare M540 had an LSD with a 2.93 ratio.
 

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After asking a lot of mechanics with previous experience in BMW engine swaps I learned that the flywheel and the clutch disk from an 850CSi will 99% fit well in the M60B40 engine. Can anyone verify this statement?

The LSD from the M5 E34 has a ratio of 3.45 not a 3.91. Now, if I put it as it is then I will have a very good acceleration but a very limited top speed (my calculation indicate a top speed of about 254 km/h). My plan is to fit the pinion of the M5 LSD into the diff of the 540 thus keeping the ratio constant at 2.93. Then the top speed will be above 280 km/h which is equal (or even higher) to a real M5 E34! Note that the extremely rare M540 had an LSD with a 2.93 ratio.
You cant put a different pinion gear onto a different ring gear? The whole reason for the 3.45 LSD is to give you good acceleration and good top speed, why would you want a higher top speed, do you race the car on a track, or drive the autobahn regally? Are you really looking for advice, or just having fun with us?
 

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Discussion Starter #6
Now it's time for the exhaust! My plan is the following: stainless steel dual pipe (no catalytic converters, no resonator) all the way and at the end an Eisenmann race M5 E34 muffler. What would be the best diameter for the dual pipes? I'm thinking anything between 2.5" and 3". What do you think? Would it be loud enough?
 
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