Ok, so here comes the third of my 'catch-up' updates......
I'm stripping down some of the engine for inspection and some refurbishment. One thing I'm looking for is the source of a rattle on first start up. I suspect worn chain tensioners......First job is to loosen the crankshaft hub bolt and then set the crank at TDC. The hub bolt put up a real good fight but I won!
Engine strip and Inspection by
Sabrebuilder, on Flickr
I then fitted my home made camshaft locking tool. The dimensions are in the Haynes manual.
Engine strip and Inspection by
Sabrebuilder, on Flickr
I take lots and lots of photo's for reference to make sure everything goes back again correctly. Here is an example...
Engine strip and Inspection by
Sabrebuilder, on Flickr
I was surprised to find that the water pump had a stainless steel impeller. No sign of any BMW logo so I presume the water pump had already been replaced at some time in the engine's life. I had already sourced the new pump shown on the left, so that will be fitted.
Engine strip and Inspection by
Sabrebuilder, on Flickr
Next I removed the single VANOS unit. Photographed after some cleaning.
Engine strip and Inspection by
Sabrebuilder, on Flickr
After removing the five screws it was immediately clear that the Vanos piston seal had failed as the piston was loose in the cavity.
Engine strip and Inspection by
Sabrebuilder, on Flickr
It was also apparent that there is axial play with a notable 'clack' sound when the helical gear is pushed and pulled.
Engine strip and Inspection by
Sabrebuilder, on Flickr
These are two common failure modes on the BMW M52 engines. These are fully described on the Beisan Systems website here....
http://www.beisansystems.com/
Despite all the warnings I managed to mess up the Vanos piston cap screw. I had to revert to welding a nut on top to get it undone.
Vanos repair by
Sabrebuilder, on Flickr
I bought a Vanos repair kit from VANOS-BMW.com. I was a little wary as they are based in Moscow but the parts are very high quality, well packaged and arrived safely. Teflon and Viton piston o-rings, new bearing ring and piston cap screw. The bearing ring was a perfect fit first time and didn't require any lapping. The kit cost £58 inc delivery and payment is by paypal.
Vanos repair by
Sabrebuilder, on Flickr
The new piston cap screw has a 17mm profile that is deeper than than the original BMW part. This part is not available from BMW as they don't expect anyone to service the Vanos unit.
Vanos repair by
Sabrebuilder, on Flickr
New Viton and Teflon rings fitted and are now a snug fit in the Vanos body.
Vanos repair by
Sabrebuilder, on Flickr
Well that's some of the engine refurbishment done successfully and one possible source of the rattle.
More updates to follow in the next few days....
....peter