Ah yes, that time again. It’s not my M3 if it doesn’t involve rebuilding the Vanos at some point.
If anyone has forgotten, I have previously rebuilt the Vanos unit on my old M3, and what a nightmare that was. Lesson learned, don’t use cheap tools.
Being that this car has 300,000KM on the clock, and the previous owner has no history of the Vanos ever being rebuilt, I felt it was prudent to do it. This made even more sense, since when I first got the car I ordered a full Beisan rebuild kit, as the Vanos was completely dead (turned out it was just a sensor issue), so had a kit sitting around.
The previous owner had the Vanos off the head back when they had the head work done, but when I asked, he confirmed that it was not rebuilt at the same time (argh, the hardest part is taking it on and off, why not do it then?!). This gave me some hope that maybe it wouldn’t fight me like the last one did…. or on the flip side, there was a chance the previous owner had been kind enough to round off the bolts or something on reassembly.
Anyway, with a nice clear day off work, I got stuck in.
I won’t do much step by step work in this post, as it’s covered in my previous rebuild, and also on Beisans website.
The inside of this engine is bloody amazing for 300,000KM. Its obviously been looked after and well serviced. The previous M3, with 100,000KM less, was almost black on the inside. This is lovely and golden brown.
Before you can do anything else you must get the engine up at TDC. This involves having the No.1 cam lobes for intake and exhaust pointing up and towards each other and making sure the crank pulley mark is lined up. I had a hell of a time last time, as the Beisan instructions are incorrect, and the timing mark is hard to find, tucked down behind the crank pulley.
Strangely, on this engine there seems to be a critical change. Not only does it have the marks behind the pulley, but it finally also has it stamped into the front of the pulley! Not sure if this was a South African Market difference or just a difference between 1994 and 1995 engines. I still had to use my old iPhone to see it, but it’s better than having to try and see it behind the pulley.
As expected this little piston nut gave me some anxiety. To undo it, you use a 7mm spanner on the nut and a 4mm 6 sided socket on a ratchet to hold the shaft still. The 4mm hex is well known for just shearing off, and then you’re having a bad day. Thankfully although it was tight, mine came off just fine.
One part I have been asked about was to give more details on the removal of the oil pump driver when removing the Vanos unit. This is a little disk that sits on the back of the unit. It’s circled here
My previous unit was so sludged up that the driver disk was stuck to the unit, but in this case it was nice and free. The risk here is that if dropped, it takes a swift one way trip to the bottom of the sump. Turns out, it’s easy to keep it in place. Use one hand to hold and pull the Vanos forward, and the other to hold the disk. There is plenty of space around it.
Of course the unit got scrubbed clean, and the engine was given a quick scrub and clean.
Part of the rebuild was to clean and test the solenoids again. I had previously done this when I redid the seals on the solenoids, but I wanted to be more thorough this time around. I got sick of having to try and jam the wires from the battery connector into the solenoid connectors, so quickly rigged up a tester using bits from the garage. Now all I have to do is plug the solenoid into the connector, plug in the 9v battery, and hit the button. Easy.
I can use the same tester on injectors too, as long as they use the JPT connector.
With the more thorough cleaning and testing the solenoids when from a nice click, to a firm crack every time they were actuated. I don’t think it’ll make a difference, but at least now I know they are working as good as they can.
I also chose to bridge the solder points. I don’t know why BMW chose to run it through that little circuit board instead of direct (it literally goes into the outer solder point, across a track on the circuit board, and out to the solenoid via the inner solder points), but this is a common mod to ensure reliability.
Reassembly was the reverse of disassembly.
So, what’s the story now? Well, the seals take a few hundred KM to bed in properly, but already the car has perked up down low and has noticeably more punch off the line. Up top is about the same, but it’s quicker to get there. It’s proper rapid.
The idle issue has not changed. This is really disappointing; I was hoping it would be the solution to everyone that is having the same idle issue, but sadly not. Back to the drawing board on that issue.
Since the WOF runs out at the start of next month I have decided to pull the car off the road shortly. I have a set of BC Gold coilovers and a purple tag steering rack to go in, along with some other bits coming from the States (thermostat, reinforcement plates etc). Once I get back from holiday, I’ll book it in for a Cert, and see what happens there.