E30 M3 Evolution III 2.5 Engine



This picture story is about my e30 M3 evolution 1 (1990) engine rebuilt.
A rebuild from a 2.3 evolution 1 engine to a evolution III engine original BMW engine housing.

Original BMW Evolution 3 Engine block.        BMW luckily start reproducing these engine blocks again.

A few differences between a original 2.3 block and a evo 3 2.5 block are:
- Crankshaft
- Engine Bore (normal 93,4) evolution 3 has a 95mm bore
- And the oil squirters, these units will set you back a 300 Euro's each.
A lot of info I found out for additional options on this site e30m3performance.com

The cylinder wall thickness of both blocks is similar, so this means there are two huge differences the bore 93,4 and 95 and the oilsquirters.

Here some pictures of a comparison of the 2.3 (old type) casting and the 2.5 Evo 3
The difference of a old type and new type casting are the reinforcements made by BMW, the original sport evo already had those, now all castings have this.

     Original 2.3 engine with no holes for a piston squirter                                    Pre tapped holes for the Evo 3 piston squirters

Detailed view of the pre-tapped holes

After searching and trying, the best and cheapest solution was to drill some holes bigger and make thread in them.
Then I modified the e36 318iS Piston squirters by making a flat back in them, so they won't move around.
The clearance with the connecting rods and the crankshaft is 2 millimeters, original it's not much more clearance.

Here some pictures of the modification.

          E36 318iS Oil Squirter (6,00 Euro's)                                      Oil Squirter installed

All four installedA High Volume Evo3 Oil Pump installed

The head was totally revived and new springs from evo 3 are installed, these are stronger as the stock ones and could cope with the more
aggressive schrick cams.

DR.Schrick cams are added for extra power, with no marks on the them for timing, it was hell of a job to do the timing on them.
We had to make slotted cam wheels to make it work.

The exhaust was also upgraded to a non cat 50/50 320iS spec one.
On the left the original thin one.

Finished NEW Race Engine!

Finished engine!
Very pleased to see it finished, almost every product was ordered with the local BMW dealer Kessels.
Some parts took very long to arrive and some parts don't exist anymore, so some parts we had to machine or re-use.

Some of the engine specs:

2.5Liter Original Evolution 3 engine block
Schrick cams 278/284
Carbon Airbox
Alpha N Injection system
320iS Exhaust manifold ( 50/50)
Full Groupe N Stainless steel Supersprint race exhaust


After installing the oilsquirters the crankshaft was next.
This also has some differences from a 2.3 crankshaft.
It's made lighter for faster acceleration, you can see the original drill holes in them.
And because of the different degrees it will make it a 2.5 engine.


The reason of my rebuild was a blown rod bearing

This blown rod was the reason for a rebuild, the engine almost had 250.000 Kilometers wich it performed superb until the end.



The new pistons are also the original Mahle BMW Evo 3 pistons.
Here a comparison of the original 2.3 and 2.5 Evo 3 pistons


                                                                                                            Inserting the pistons


First filler coating                                                                                        Paint Job Done! (BMW Bornit Metallic)


After spending so many hours non stop sanding, welding and painting the car, then it gives joy to see it getting coming together.
The color of the car is a original BMW color, called BORNIT METALIC.
Only 6 cars, all 850i were made with this color and it was a "sonder serie farbe" saying a special edition color.
With only 6 cars made with this color, it was a problem of course choosing the color, because you have no example how the car would look like in real life.
So I took the gamble and for me it paid of, it's a stunning en every angle and lichting

Getting started


And a few pictures and a little movie of the finished car of course


for movie --->   click here   <-----

Finished, guess not, with a hobby you're never finished, so the story and add-ons continue....
With the setup made, the car wouldn't come to it's full potential.
So there were some upgrades made.
First I bought a big Alpha N kit, wich allows us to fully map the new engine with it's specs.
I didn't found any reliable chipper who could make a chip at a normal prize.
So I invested in a MAXX system, wich allowed me to map it myself and it was a very good investment.
And a Innovate Motorsports LC-1 unit with WbO2 sensor and gauge to do the readings.
The MAXX kit has a big upside, it's in continue development, so software update, even hardware updates.
There is a big community who drive with this set-up, so a lot of feed-back and help.

I also changed the injectors to bigger ones.
OEM the 2.3 has 260cc injectors and my engine now upgraded tot a 2.5 wich original uses 300cc injectors, I had to upgrade my 260cc too.
I went for the Volvo turbo 330cc's green injectors.
I had them professionally cleaned and tested.
So I couldn't resist comparing the 260 and the 330 on the test rig.
Here some results, we were looking for spray pattern differences, obviously the 330 would deliver more spray in a duty cycle.
In the left corner wearing the green trunks the 330 and on the right corner the 260


Further upgrades wich will be installed in the next weeks are a Sport Evo 3 (almost 5kg lighter) flywheel
And a new sachs clutch.

And I build in some Magnecor KV-85 competition spark plug wires to change the old ones.
I ordered them with a Dutch distributor wich I really can recommend for using.


A new movie with all above installed, running strong at 8000RPM
>>>>>Click here<<<<<

to be continued..............