Possible spun bearing

[pinwiz]

Hello all I have an 04 330 CI zhp with the 6 speed manual. I have had some engine problems and am now starting the project of fixing it. I have heard several people say to replace the engine instead of rebuilding it. I plan on opening up the oil pan and bottom end to see what the damage really is. Hopefully nothing drastic and I can put it back together. What I am wondering is while I have it torn apart what should I do to the engine preventative maint. wise. I know that I need to replace the fuel injectors, I think that leak down caused my whole problem. I have seen the vanos rebuild with the different o rings. I plan on doing that. The car only has 75000 miles on it and I want it to last if I am going to dump a few grand in it. Thank for helping a newbie out.

[BMWCurves]

What prompted people to suggest you need to replace the engine? 75k miles is not that many miles.

[ELCID86]

What engine problems...?


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"ZHP is a garbage option anyway- just some cosmetic upgrades with a different cam and diff to claw back some of the performance lost fitting those hideous and heavy wheels. Any 330 with a 3.46 diff will smoke a ZHP every time. The whole Mafia thing reeks of childish behavior." - anonymous E46 fanatic

[pinwiz]

The dealership did some mild troubleshooting and told me that I was looking at a possible spun bearing and rebuilding the engine was going to be very expensive. Even worse than replacing the engine with a used one. They wanted 800 to drop the oil pan to look at the bottom end. I did not want to pay that so I had it towed home and it has set for a while. I have time to mess with it now and I am going to do my own investigation. It was clacking while it was running the dealership removed spark plugs on the top end and when they pulled number 5 it got quieter.

[BCS_ZHP]

A spun bearing will usually make a noise under load initially and then all the time as it gets worse. That the noise quieted down when #5 spark plug was removed sounds like it might be ignition or fuel related. Try swapping the coil on #5 with the coil from an adjacent cylinder. If the noise moves to the other cylinder then you have a bad coil. If the noise doesn't move to the other cylinder, try the same swap and switch detective work with the injectors too.

Rattling on #5 sounds like a detonation issue on that one cylinder, hope this helps you track it down.

[BCS_ZHP]

Been thinking about this some more today. So if you do the coil & injector swaps and the problem stays only on cylinder #5, then they're probably right that it's a bad bearing at the crank. If there's any undue slop in the bearing at the crankshaft, the spark initiation of the power stroke would force the piston & rod assembly downward and it could make a mechanical noise as it struck the crankshaft bearing face. With the engine running at 700-800 rpms at idle, it's repeating that about 6 times per second and that would likely sound like a rattle. Them removing that spark plug took away that pressurized/forced downward movement of #5 piston/rod assembly and without that you wouldn't hear the mechanical noise. I still try the coil and injector swaps first since that's easier than removing the oil pan.

[Oli77]

Bruce! You da man!

[pinwiz]

Been thinking about this some more today. So if you do the coil & injector swaps and the problem stays only on cylinder #5, then they're probably right that it's a bad bearing at the crank. If there's any undue slop in the bearing at the crankshaft, the spark initiation of the power stroke would force the piston & rod assembly downward and it could make a mechanical noise as it struck the crankshaft bearing face. With the engine running at 700-800 rpms at idle, it's repeating that about 6 times per second and that would likely sound like a rattle. Them removing that spark plug took away that pressurized/forced downward movement of #5 piston/rod assembly and without that you wouldn't hear the mechanical noise. I still try the coil and injector swaps first since that's easier than removing the oil pan.

Thanks I'm Going to try that first. Then I will start looking at the bearing.


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[Scott ZHP]

Very first thing I'd do is inspect the oil filter and the engine oil, assuming it hasn't already been done. If you've spun a rod bearing, you'll probably know it.

[pinwiz]

Update. I pulled the oil pan and disconnected the bearing cap. And no problems. The number 5 bearing has no signs of problems. Pulled the number 6 to make sure and the wear was almost identical. There were no signs of metal in the oil or on the filter and the pan was clean as well. So while I had it all torn apart I changed the injectors and spark plugs. The number 5 plug had quite a bit of carbon on it.
I started it up and the clacking noise is still there. Notice that the noise is a clacking not a rattling as I first stated. My wife and I have different definitions of noises.
My father was present when I ran it this time and he used the old school screw driver against his ear technique. According to him there is no mechanical broken noise.
With what we have done I am leaning to a collapsed lifter.
Any ideas about figuring out if that is it. I am willing to tear it apart to fix it but I don't want to tear it all apart and that not be what is wrong.
Thanks.


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