# 2001 318I E46 - M43TU engine - metal pieces inside cylinder



## glenn (Dec 4, 2005)

Hi All,

Our 318I E46 Touring with an M43TU engine suddenly started a loud top end rattle.

I've taken the cylinder head off and found pieces of metal sat on top of the No.2 piston and one piece rattling around in the lower inlet manifold, see photos.













































In the first 2 photos the left-hand and middle pieces were in the cylinder and the right-hand piece was in the inlet manifold.

The cylinder bore is not scratched, the top of the piston is not cracked or broken, the valve seats are not marked, the valves do not appear bent or damaged. The only damage I can find is where the pieces of metal have been hammered between the top of the piston and corresponding area of the head.

I've looked around the various engine components/parts but can't find anywhere the metal pieces have come from. Any suggestions on what to do next or where the bits have come from would be much appreciated.


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## glenn (Dec 4, 2005)

Update,

I may have found the culprit.

The lower inlet manifold has a device called an 'adjuster unit' attached to it. Looking from inside the manifold the adjuster unit has a straight solid metal pin extending from its centre to just short of the plastic vain of a butterfly valve, located between the 2 inlet ports of the manifold itself. Should this pin connect to anything at the butterfly valve end? Cos it doesn't on mine.

On the 'adjuster unit' side, of the butterfly valve vain, are 2 horizontal reinforced mouldings in the plastic with a metal bushed hole between them. I'm wondering if the pin from the 'adjuster unit' should be attached to the butterfly valve vain through these holes and that what ever does the actual attachment has broken off?

I've tried taking photo's but they don't come out clear enough.

Any thoughts would be much appreciated.

Regards.


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## glenn (Dec 4, 2005)

I've pretty much established where the pieces of metal found in our BM engine cylinder came from. The end of the actuator arm, connecting the DISA unit actuator to the DISA unit butterfly valve vain, is missing. I guess it snapped off, got sucked into the engine and broke up; although the actuator arm is round in cross section whereas the metal pieces found are squared off, so maybe I'm wrong?


Wherever the pieces came from I have to establish the likely damage, which appears limited to:-

* The top of the piston and the corresponding area of the head being hammered and pitted with some sharp burrs sticking up, as seen in the photo's.
* The spark plug ground electrodes which are bent.
* The finger rockers having jumped of the valve stems
* A couple of small burrs on the finger rocker tip edges in the non-contact area.

As far as I can see:-

* The cylinder bore is not scratched, scored or marked.
* The hammered and pitted areas of the piston and head do not appear cracked or have pieces missing.
* The valves do not appear bent or damaged, though some small grey marks could indicate embedded metal particles in the mating/sealing faces.
* The valve seats seem OK but could do with re-lapping, though some small grey marks could indicate metal particles embedded in the mating/sealing faces.

In addition to the above, the engine did have a small coolant leak that I could not find and had got very hot on a few occasions. While taking the head off I found its rear coolant pipe connector broken; a common failure apparently and quite likely the cause of the leak.

I'm thinking I'll get the head skimmed and scrape the top of the piston, to take off the high spots of the hammered damage then put it all back together using new gaskets, head bolts and secondhand DISA valve, that is, unless someone recommends differently.

As a note the engine has done about 132K miles.


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