[Kirky87]

My car is Automatic. I assumed it only has torque converter. Which we replaced

I've had no issues With transmission.

Only thing I havent done is run car without belt.

Could it be besrings in water pump maybe?

[drymite]

Its a electric waterpump so the belt wont effect it. But try running it without the belt to confirm its not the AC compressor thats causing the knocking

[Kirky87]

I have seen the video on YouTube of the guy that thought he had rod knock.

I've managed to zip.file the video.

Cpuld you let me know what you think.

[drymite]

Sure upload it i can try... tbh though with my experience with RODknock.. it will be filled with metal shavings everywhere if the engine is ran with it knocking and any WOT would blow it n sieze if you have been driving for a while and no metal shavings its most likely the compressor or a bad pulley

[Kirky87]

So after rod bearings where changed, I actually went to bmw to see there opinion. They didn't listen and went straight to the bottom.end and inspected tye work my local Indy Shop had done. New bearings where sound, they did say there was a very small piece of metal in bottom of the pan. I think from tye bolts ect.
Car has been driven normally for a good 2500 to 3000 miles now. Its not driven hard all.the time, but I've done enough pulls to know she feels and behaves perfect.
I've heard rod knock and piston slap, mine not deep enough for that plus all.the positive work that's been done.
Checked filter last weekend after new filter had done 500 miles, nothing at all in the filter.

I'm just finding a way to get the file online as it's too big and even a zip file is too big.

Guve me 10mins

[Kirky87]

https://www.dropbox.com/scl/fi/eea7i...fbupa7wsl&dl=0


Let me know if this works

[SlowE92]

I once had an injector plate that was loose, and the O-ring and decoupler were toast. The injector was bouncing up and down and made it sound like rod knock.

[Kirky87]

Would you physically see the injector moving?
I've had all injectors tested and refurbished (seals)
I have had the stethoscope all over the engine,

Thing is sound travels.

But I did put the stethoscope on the fuel rail and does match the space almost.......

I bloody hate this n54 game spent to much to give uo

[Kirky87]

https://www.dropbox.com/scl/fi/eea7i...fbupa7wsl&dl=0



*does the link work OK for you to listen*

[SlowE92]

Originally Posted by Kirky87

https://www.dropbox.com/scl/fi/eea7i...fbupa7wsl&dl=0



*does the link work OK for you to listen*

Thats definitely isn't rod knock. Rod knock has a dull sound, this one is more high pitched. I haven't read the whole thread but it sounds more like lifter tick to me. If you rev the car does the sound get louder or go away?

[Kirky87]

So lifters have also been replaced full set.

It's a right mystery.

No doesn't get louder, just is roughly half engine speed all the time, so obviously noise increases in rpm. But doesmt get louder.

You actually can't hear it at all driving. No unless your in.your Street slow.driving past otyer cars.

[Tambohamilton]

Originally Posted by SlowE92

Thats definitely isn't rod knock. Rod knock has a dull sound, this one is more high pitched. I haven't read the whole thread but it sounds more like lifter tick to me. If you rev the car does the sound get louder or go away?

I disagree about the lifter tick, but agree it doesn't sound like rod knock...

I'd take the accessory belt off and test, just to rule out those parts.

If you rev it without driving, does the sound get louder or quieter when revving or on overrun?

[Kirky87]

The sound and pitch stationary or driving is exactky the same doesn't change.

But it's always there.

Cold or hot engine doesn't change.

Currently using 5w30

When you rev it it jist matches rpm with pace if you get what I mean but doesn't get louder.

I know if it was a piston ring it would not sound as bad warm.

Leak Down test came back perfect so kinda rules out bent valve.

Compression test was slightly lower than expected. 175 to 180 ish

[Tambohamilton]

If the sound doesn't change at all with load, then that basically rules out crank/rods/pistons I'd say. Doesn't sound like a bottom end knock anyhow.

It's probably not the HPFP either - apparently they can also make noise, but that would vary with fuel pressure/load.

To me it's something in the top end, though you've gone over all of that already... Have you replaced timing chains and tensioners?

[Kirky87]

HPFP was replaced by previous owner 3 years ago. Car hasn't done many miles since then at all.

Apprently timing chain was ok. All beem checked when cams and lifters where done.

I think next step is to take Belt off and see if its any of the pulleys.

[Kirky87]

The sound doesn't get louder or quiter ever stays roughly the same, obviously when you out revs on you can hear it more as on it picks up pace wity tye revs.

I've driven nearly 3000 miles with it like this after all the work was done(bottom of page1)

My mechanic is at a loss

[Kirky87]

I'll send a new video on Saturday of whst it sounds like revving.

I work away all week

[Tambohamilton]

When I changed the chains and guides on my partner's N47, I couldn't see any significant wear...but they definitely made noise before, and haven't done since. Food for thought. Granted it's an entirely different engine, and they only made a scraping sound not tapping.

Yes, taking the belts off is a sensible thing to try. Video when revving will be useful too.

[Kirky87]

Thanks Tambo will message at weekend.

Thanks everyone for advice.

Video link on Saturday