D2 4.0 How long can I continue with slipped Top Hat liner

Attachment 149457Attachment 149457

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Originally Posted by ballbag

Any chance of a video of the sound please?

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I must admit it sounds tappety to me but then those in the know say that a liner does sound like a tappet but not in all occasions. Usually a slipped liner will make no noise when cold but sound like a tappet when hot.

So does it make the noise when the engine is cold? If yes then likely a tappet, but if only when hot most likely a slipped liner but also could just be a tappet.

Yes I was thinking that a flanged liner could only possibly move a bit if the fire ring of the head gasket was outside of the flange. But AFAIK the fire ring is usually on the flange which would mean the liner could not move unless it was not fully pressed in and then the block was machined flat with the liner not fully down. Surely an engine builder would see a liner sticking up! Or the groove machined in the top of the block was too deep and the liner was only pressed until it was flush with the deck.
Before you go removing the engine, pull off the inlet manifold and have a good look at the cam and lifters.
I had a cam fail a lobe which beat a lifter to death, and it made a clacking noise.
Regards Philip A
Also have a look at the rockers. It is not unknown that the steel insert that the pushrod sockets into fails and drops out.

Thanks for the sound recording.

Can you hear it at higher rpm or only at idle?

I have had a similar noise for about 100,000km.

Engine was apparently top-hatted at 200,000, has now done 300,000. I'm assuming it still has original cam, lifters and timing gear. So she's tired, but runs like a champ.

Gets noisey once engine nears operating temp but only at idle, so this gives me some inkling that it's related to oil pressure, so possibly a tired oil pump and shot cam lobe/lifter.

Does not use any water, runs below 90c in all conditions with an 82c thermostat. Symptoms appear same as yours.

Makes a big 'crack' sound cooling down after shutdown. Does yours?

hard to tell from that file,, my standard liners made loud metalic TAPS when THEY moved( yes I had two move),, the volume of noise made it hard to go past a liner.

Apart from Phillips reason,, for a tophat to do this the cutout for the tophat rim must be too deep, which would explain the small amount of sound because of the small amount of movement...

and IF thats the case the engine will soon bypass the fire-ring,, and blow the gasket..

Quote:

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Originally Posted by ballbag

Makes a big 'crack' sound cooling down after shutdown. Does yours?

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I'm sorry.. it does WHAT?
fron the engine??

Listening to the noise it seems to me to be at half engine speed .

I would say about 4 per second . at 500RPM per minute the noise if a liner would be much quicker IMHO or about 8 times per second.
So I think it is something to do with the camshaft.

Regards Philip A

Quote:

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Originally Posted by ballbag

Thanks for the sound recording.

Can you hear it at higher rpm or only at idle?

I have had a similar noise for about 100,000km.

Engine was apparently top-hatted at 200,000, has now done 300,000. I'm assuming it still has original cam, lifters and timing gear. So she's tired, but runs like a champ.

Gets noisey once engine nears operating temp but only at idle, so this gives me some inkling that it's related to oil pressure, so possibly a tired oil pump and shot cam lobe/lifter.

Does not use any water, runs below 90c in all conditions with an 82c thermostat. Symptoms appear same as yours.

Makes a big 'crack' sound cooling down after shutdown. Does yours?

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@ballbag Its more difficult to hear at higher revs but is still there. It had a new can and lifters , a lifter was suspect so another new set of lifters was put in still the noise though. Oil pressure is good but did have a new timing cover plus oil pump gears. Doesnt make any noises on cooling down though. It did overheat for some reason but a change of thermostat and temps are fine I do have independent temp monitoring and alarm.

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Originally Posted by Pedro_The_Swift

As Garry says,, cant move.

Does it run ok otherwise? not missing or using coolant?

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It did seem to lose coolant and did overheat but I changed the thermostat stopped the overheating and put a new overflow bottle cap as I suspect the old one was releasing to early now all seems ok i.e no coolant loss doesnt overheat???

Quote:

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Originally Posted by PhilipA

Listening to the noise it seems to me to be at half engine speed .

I would say about 4 per second . at 500RPM per minute the noise if a liner would be much quicker IMHO or about 8 times per second.
So I think it is something to do with the camshaft.

Regards Philip A

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Really appreciate your thought and math on this :-), the sound just isnt regular in pitch/tone or harshness, I will try an time it myself an check revs then try with higher revs. Interesting if you load up the engine i.e in gear foot on brake and releasing clutch a little to load up the engine noise doesnt change I thought with a liner it would get worse. Am really at a loss and I while I would pull the engine if I knew it could be easily fixed I would with this engine you cant even just pull the rocker covers like the old 3.5 and double check the cams etc...BMW has a lot to be sorry for :-)