Jump to content
Kit

520i M50tu to 525i M50tu

Recommended Posts

After much deliberation I decided to go for the simplest option to get a little more grunt in my 1995 touring - upgrade to the 2.5 lump.
 

This was helped by both this forum and finding a car that ended up being at a friends brothers garage in the north east. A one owner 525i saloon with 112k on the clock. Failed it’s MOT on rust but runs well. After some haggling it was put on a trailer this morning by a tow company I found on Shiply (see below).

 

It’s off to Angus BMW in Colchester where we will asses the car then take as much off it as possible to improve mine.

 

By the end I hope to have more power with the same reliability I have enjoyed with my current smooth and trusty 2L engine.

 

A lot of this car (including the 525i auto box) and my old M50b20tu will be for sale so please message me if interested, could do a deal on the main parts or sell it all as a job lot.

 

Thought I would do this project during these strange times as it’s both interesting and quite exciting. Sure it won’t be plain sailing and a bit costly when all is said and done but hey, that’s to be expected.

 

I love my e34 touring and want to keep it long term, don’t see many on the road anymore!
 

AB969D12-AC82-46FC-B262-D0BB634B63F0.thumb.jpeg.1b9cd6729dca67607308e3a427488daf.jpeg

 

3A1F2DF6-73F1-4B87-B8CE-31F77B7ADE9A.thumb.jpeg.6b03c00f0fdf96727ccc11ac4015c604.jpeg

Edited by Kit

Share this post


Link to post
Share on other sites
2 hours ago, lozmccall1 said:

Very interested in this. Like you I can't help but wander what a bit more power would be like (although I've already got the m50b25 in mine). Will you be doing the work yourself or getting a garage involved?


Taking it here to have the work done - https://www.angusbmw.co.uk/conversions/

Share this post


Link to post
Share on other sites
3 hours ago, coupe king said:

Wow, you don’t mess about!!! I can see why you are keen, your touring looks like a cracker.

 

Thanks, yes it cleans up well, but so it should after the money I have spent on it in the last 4 years! 
5D781609-16BE-434D-84B7-C24446761F65.thumb.jpeg.05b6846937add89a83cc88e92d1abb31.jpeg

 

Talking of cleaning, amazed at how well the once oil marked and generally dirty boot carpet cleaned up with a bit of elbow grease and Autoglym interior shampoo. 
C24D61E2-FD63-4C6B-A462-F7BB0C32D84D.thumb.jpeg.fe95f615b34c9343e019019fce81598b.jpeg

 

Share this post


Link to post
Share on other sites

Had to source a new rear box as the donor’s was rotten, found a used but sound oem one in Denmark so it’s on its way. 
 

Question - how painful is it changing the details on the V5 once the conversion is completed?


Guess it will still be labelled a 520i but with 2494cc cylinder capacity and a change of engine number. Also guess I will have to inform the insurers...

Edited by Kit

Share this post


Link to post
Share on other sites

The used oem 525i rear box arrived from Denmark. I’m a factory spec man so hoping the rear AC Schnitzer tip comes off cleanly.

 

If anyone is in the market for one let me know.

 

7861D215-912B-46B9-8C54-2055BE57C4BB.jpeg.50cbc8af42bc2c749d01482fe05af425.jpeg

 

121BA412-C986-4BED-8528-FC7DFE65CE20.jpeg.7502467b0b9d138d59e962134cf1dba0.jpeg

Edited by Kit

Share this post


Link to post
Share on other sites
On 29/10/2020 at 18:11, Kit said:

Guess it will still be labelled a 520i but with 2494cc cylinder capacity and a change of engine number. Also guess I will have to inform the insurers...

 

I recall someone had some cheeky ideas around this. @Sir Anthony Regents-Park :ph34r:

 

Keliuss

Share this post


Link to post
Share on other sites

Dropped the car off today so hopefully this time next week it’ll be running smoothly with 0.5L more than it started with. 

 

Obviously needed to get some oil so went for Castol Edge 5w-40 fully synthetic as got a good deal. Out of interest what do you guys use? Guessing a decent 10w-40 semi will be popular choice? 

Edited by Kit

Share this post


Link to post
Share on other sites

Castrol edge synthetic 5w40 as per their online oil selector, its what BMW garages used to use

 

I believe BMW garages now use Shell oils

Share this post


Link to post
Share on other sites

Pretty irrelevant what brand the BMW dealers use, it is just a commercial deal.

 

In my old M50 non-vanos 320 I used to use Fuchs 5w-40 full synthetic, and that had done close to 200k miles when I got rid of it. Engine was still sweet and used no oil that you could see on the dipstick. I had used Mobil 1 0w-40 a lot in earlier years but moved to the Fuchs mainly because of cost.

Edited by Tuvoc

Share this post


Link to post
Share on other sites

My Danish oem rear exhaust isn’t so oem it turns out, not only have the front pipes been cut short so have the back. Bit of extra work for the Buchanan brothers...

 

5F577931-1E1C-4298-B7AD-747FEE1CCCCD.jpeg.9991e4b30b59394378a97ce960189050.jpeg

 

313A706E-AB8D-4A63-997C-F364C3DF7274.jpeg.d49dab6067fdc77e08882619bc7c1772.jpeg

Edited by Kit

Share this post


Link to post
Share on other sites

The engine is in and has been tested over the weekend, apart from a faulty temp sensor the install has gone to plan.

 

I know the 525i has a different diff etc but I’m keeping my 520i running gear. What if any difference will that make to a full 525i setup? Hopefully it’ll just feel more powerful and the other differences will be marginal. 

 

Will be able to drive it post lockdown. 

Edited by Kit

Share this post


Link to post
Share on other sites

Bear in mind that the 2.5litre has about 30% more power & torque over the 2.0litre, I'd take a good look at the brakes. The 2.5litre car had bigger Discs & Calipers for that very reason.

 

C.

Share this post


Link to post
Share on other sites
3 hours ago, cableguy said:

Bear in mind that the 2.5litre has about 30% more power & torque over the 2.0litre, I'd take a good look at the brakes. The 2.5litre car had bigger Discs & Calipers for that very reason.

 

C.


My 520i is a late model and came with vented discs and the bigger callipers from the factory so luckily they don’t need to be swapped from the donor. 
 

I spoke too soon as far as the engine goes, had a call saying it’s not starting and after an inspection the crankshaft sensor may have an issue - so a little extra work to do still. 

Share this post


Link to post
Share on other sites

Latest update is that the car runs well but doesn’t enjoy starting. Camshaft sensor changed and ecu swapped but neither have solved the issue. 

 

Odd as when it was first installed all seemed fine, only after they tested the car for a weekend it didn’t want to start on the Monday. Guess it must be some sort of electrical issue as it’s nothing obvious like the starter motor I’m being told.
 

In other more positive news the oem black tips arrived, hopefully they help elongate the sawn-off tail pipes...

 

8D759927-D0C9-4F52-A3B8-8A3F8B68A108.jpeg.c2cdc7e3b7e0b50a3be76f423492222d.jpeg 

Share this post


Link to post
Share on other sites

The car is done, tested and ready to pick up. The donor is going to my body guy Tom Martin at Lemass Automotive (he’s very slow and rarely hits deadlines and he owes me a few favours, but we get there in the end normally), want to pillage some of the dash and interior mouldings which look much fresher than mine. This was the bonus of having a donor in the same colour in and out. I also sourced some front touring doors that are not rusting at the bottom like mine so they will get painted and go on too.

 

Incase you are interested this is the work done and the parts bought.

 

Work

 

- Remove engines from both cars, roughly paint engine block of 525i and clean engine bay.

- Fit 525i engine, ecu etc into 520i.

- Install new clutch.

- Fit new drive belt, air intake bellows and air pipe.

- Fit oil filter and fill with customer supplied oil.

- Swap alternators.

- Top up power steering fluid.

- Swap over thermostat using new O ring and profile gasket.

- Fill with antifreeze/water mixture.

- Fit exhausts from donor car and customer supplied parts.

- Welding in sleeves to make exhaust system join.

- Remove grills from both cars and swap over headlights to ensure removable bulb holders would function / open from rear.
- Fit one new headlight adjuster and 6 headlight "top-hats".

- Fit fog light.
- Swap over engine temperature sender from 520i engine to 525i.
- Check for no power at cigarette lighter, trace wires back to fuse box, check power at terminals, eventually find relay fitted wrongly, refit relay.
- Swap over glove boxes and fit with correct lock.

- Check and adjust handbrake.

- Remove all wiper parts from both cars and fit 525i mechanism to 520i.
- Fit lower windscreen covers using some new clips. 

 

Parts:

 

5w40 Oil

Rear (second hand) oem exhaust 

Headlight adjuster.

6 Headlight "top hats".

Oil filter.

Drive belt.

LUK clutch kit.

2 x exhaust brackets.

Exhaust pipe section.

PAS fluid.

Antifreeze.

Themostat O ring.

Thermostat profile gasket.

5 x windscreen cover clips.

Air bellows.

Air pipe.

Oem black tips (yet to be installed)

 

The total cost was reasonable and the Buchanan brothers are very friendly and knowledgable. 
 

Looking forward to driving it, it’s been a while...

 

Kit

Edited by Kit

Share this post


Link to post
Share on other sites

While I’m at it if you, or anyone you know needs some e34 parts / the whole thing let me know. I will soon have a lot for sale.

 

Big stuff:


Smooth M50B20tu engine 

525i Gearbox (auto)

525i rear end / dif

525i vented disc / callipers 

Silver grey saloon interior 
520i middle and rear exhaust, only 2 years older.

 

Ideally the donor car will be sold whole for the right price early next year. But DM me if you want to chat. The 520i engine is particularly sweet.

 

Thanks 

 

Kit

Share this post


Link to post
Share on other sites

Just driven it back home from Colchester.

 

It does feel different, more grunt and generally a bit beefier, the extra torque is noticeable, especially in 4th and 5th.

 

I’d say over all its slightly less smooth than the b20 but I also think everything needs running in a bit including my new clutch. 
 

Apart from it having a few intermittent and brief high idles it was a good run, will put some high octane fuel and some redex in (on the off chance it helps clean things up a bit on an engine that has sat for 2 years) and take it for another long run this Christmas hopefully. 

 

It somehow feels a little heavier to drive but I think that’s to do with it being a little less free revving. Defo faster...

 

A9DFA79C-2721-4F18-8EFB-916D3DF4DE32.thumb.jpeg.42eae3536d92f4bf1addc449d2414fd2.jpeg

Edited by Kit

Share this post


Link to post
Share on other sites

Nice update, looks like a job well done

 

i love the m50b25 in mine - fuel consumption is a bit higher than expected, but have a new thermostat to go in to hopefully remediate that (runs cool).

 

in yours, as it had been standing,  I’d be tempted to change oil, filter and coolant within 500 miles or so, and treat what you’ve done to date as a flush.  FWIW, I used Millers Trident 5w40 in mine -  I tend to use any 5w40 with a Porsche A40 approval, and this was £21 for 5 litres delivered.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×