M52/M54 into Defender Bellhousing bolt patterns

[HazleNut21]

Hi All,

First post, I've been researching and reading a few of the build threads on here and on other forums for a while and am intrigued at the idea of a BMW petrol 6 in a Defender. I have seen lots of comments about using the 2.5 bellhousing from a P38 to mate the engine to the R380, but was wondering if the bolt patterns on the M52/M54 are the same as those on the back of an M57. Might be a stupid question, but seeing as they probably went into the same vehicles with the same boxes, I thought there might be something in that.

My next question would be, if they are, could you simple mount the engine to the R380 using a M57 conversion plate from mwmmachines?

Feel free to educate me on where I have made some naive assumptions, I'm in a bit of a research phase at the moment to see what sort of work it would involve, main concern being mating the two together without finding obscure 2.8i parts from the southern hemisphere

[Blanco]

Welcome, ...

BMW conversions are a thing and you will find there is plenty of knowledge out there if you dig a bit deeper. As I understand it (although I haven't lined them all up myself) M52 and M54 are essentially developements of the same architecture, and the M57 is the direct injection developement of the M52; so a qualified yes. BUT there are early and late bolt patterns (M57 5 series changed over in about 2006 I seem to remember). 

There are a couple of FB groups specifically catering for it and there are a couple of options for adaptors, even keeping the BMW gearbox and adapt the xfer box instead.  Many options and few people do it the same way exactly, it still isn't a bolt in job though depending on your defender you will still need to adapt the ancilliary sytems to suit and need good skills if you are to do it yourself . 

[tommobot]

I've a M52 mated to a V8 flavour R380, though it can be done a P38 bell housing and adpater plate behind the bell housing from memory and a pull clutch arrangement with again an R380.

I used the V8 bellhousing and box as I aready had one, and was assured it was a working combo, though in hindsight it appears the input shaft of the R380 wasn't quite long enough and needed extended which was an expensive headache!

The ashcroft V8 autobox to M57 adapter is what I've used to mate it all together.

A ballache for sure, but at the end its a lovely drive with the M52, sounds sweet and goes properly when wound up!

[muddy]

AFAIK the P38 bell housing will fit but this uses a poor and expensive pull clutch. it also has a shorter input shaft than the V8 and Tdi gearbox. Early conversions used a spacer at the gearbox end of the bell housing if you don't ant to swap input shafts. you can also make a mount to use a kia concentric slave cylinder to use a standard clutch. This is a route I am thinking about trying to fabricate but I am trying to find a reasonably priced solid flywheel.

Synchro now do an adaptor ring with or without flywheel that allows you to bolt a tdi box straight on. 

 

[smallfry]

I believe the bolt pattern is the same, BUT on the M57 there is a "small" bellhousing, and a later larger one. The Ashcroft adaptor is for the earlier smaller type.

I know nothing about the petrol engine setups though, although ISTR reading something about the petrol engine/s being tilted at a different angle, but I have no idea if this was for a particular application, or petrol engines in general. Something else to consider !