M10 chain tensioner question

[capnmchl]

Not the most popular engine, but here goes.

My engine has been making a rattly noise for a while now from the top end, and I've decided to change the chain tensioner. The only other things I can pin it down to is the valve clearances, but I've done them a couple of times now and they're still spot on, or the need of a thicker oil (running 10/40 semi at the moment.)

http://www.realoem.com/bmw/showparts.do ... g=11&fg=25

I digress though. I ordered the chain tensioner, spring and ball bearing (items 15, 16 and 17 in the diagram linked above) through cotswolds the other day.

Now according to autodata, if you blow through the tensioner one way, it should flow through, and if you blow through the other way, it should block up. I assume this means there is already a ball bearing inside the tensioner, and the ball bearing I ordered actually isn't needed.

So what I'm looking for really informed people, is whether I need to put that ball bearing somewhere else (just inside the piston where the spring sits?), or if I don't actually need it at all.

Cheers

[Andyboy]

The rattle will probably be a shagged cam sprocket - they wear very badly on the M10. A new one is about 30 quid. They wear so badly that the chain eats into the gear and the tensioner can't cope. They are easy to fit as well, cam cover and upper timing cover off, remove the tensioner plunger and four 10mm bolts to swap the sprocket.

[capnmchl]

It didn't make the noise until I took the engine out during the refurbing of my suspension and did the chain cover gaskets. After I put it back together and did the valve clearances, it started making this noise. As I said, I've rechecked the valve clearances and I've had a garage check them and the noise is still there.

The only other thing I've disturbed is the chain tensioner. which makes me think taking it out has upset it somehow.

Changing the gaskets was a waste of time anyway, as it leaks badly where they come up against the head gasket due to the gaskets being too big and me being in a rush to get them fitted

I'll have a look at the chain sprocket however.

[capnmchl]

Okay, looking into this a bit more, the ball isn't needed, as it's the one inside the tensioner. It's simply the schematic confusing things. And there's a possibility I didn't bleed the tensioner properly when I put it back in, which might mean the only tensioning is being done off the spring. So I'll install the new piston and check the cam sprocket and bleed it properly and see what happens.

[capnmchl]

I changed the tensioner and the oil and filter, and had a look at the cam pulley.

I thought the noise had gone, but by the time I'd driven 20 miles and the car and oil was nice and warm, it was back, although much quieter. Now this might be down to the new tensioner (I couldn't hear the ball bearing moving around in the old one and it was a bit oiley to be blowing up and down it) or due to the fact there was new oil.

Guess I'll have to try this crank pulley.