This may sound crazy but I am known for such things. Can you take a borescope, pop it through the oil cap opening, make sure you place it in a position out of harms way but able to see, then turn the car on and look around. It seems that static imaging is not revealing anything to you.
Solved - bad engine noise!!
- Thread starter Stevehose
- Start date
Wow, the first one sounds like when my son forgets something valuable in his pockets and it makes it through washer and then dryer. Something loose being thrown around. The second looks like an in-place phenomenon...Does it just jump randomly between these two regimes?
UPDATE: I decided to check valve clearances AGAIN and #2 exhaust valve was way out - I could slide a .15 feeler gauge through it, I normall keep the valves at .10 so I adjusted back to that. However I noticed when tightening the 10mm eccentric nut it wouldn't tighten up to my liking, like it was half-stripped. So I pulled it and found the nut to be stripped:
So now to replace this then try running it again.
Question: could a rocker at .15 make this much noise? It plays into the symptoms of not making noise until at least close to idle speed. Update in due course...
So now to replace this then try running it again.
Question: could a rocker at .15 make this much noise? It plays into the symptoms of not making noise until at least close to idle speed. Update in due course...
Good find (even if it is not the cause of the noise, but maybe?).
cam sprocket for timing chain: mounting bolts or flange damage, or cracked chain guides? Wiggle the sprocket?
Can you look over the chain guides with a borescope the tunnel?
Can you look over the chain guides with a borescope the tunnel?
So Steve - further to skk's post, didn't you report that you had sought to replace your timing chain guide only to find that the replacement part was defective? If I remember this correctly, you kept the old chain guide.
The eccentric not being tight can cause some of the erratic noise, where it can be pretty steady but then turn into one of those occasional tick tick sounds.
Just read up on this adventure...man, what a roller coaster ride! Sorry you're having to deal with this.. It does sound very much like valve clearance..the thing that gets me is how perfectly rhythmic it is, not at all like something bouncing around. Hopefully that clearance adjustment fixes it, but it very much sound like valve train noise, to me. Staying tuned to see if it's cured!
stphers
Well-Known Member
That bolt looks pretty beat up as well. It could easily be the noise, the concentric will move around and at some time , be in a position where it is at the right clearance and be quiet for a second or so. How does the rocker and rocker pad look like? Do you need a new bolt and nut? Heading to the US tomorrow AM and could send a couple out to you Let me know
Thanks, Rick
Thanks, Rick
I've checked the sprocket and chain guides which are new from my piston job a year or so ago. @Ohmess I believe you are referring to the tensioner arm which yes, the first time I left the original in, then when I did the chain guides I altered one of the new crappy ones per Don's suggestion to get it to fit the tensioner piston angle correctly. I put a new nut on the eccentric bolt and it is tight now but I went ahead and ordered genuine BMW eccentric bolt and nut for the long term. While I wait for those I will start it up tomorrow to see if the noise is still there or not.
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Thanks Rick I just ordered a couple each so should be here in a few days. I will inspect the rocker pads again but I checked them all before and they look good.
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I was going to suggest that since Bfeng is the top dog of the automotive sound section of BOSE, that after finishing up my "spouse cancelling" headphones, he create a set of "engine cancelling" headphones for you.
Yes I could use those, I put the valve lash back to .10 on the offending exhaust valve rocker, put a new nut on and tightened it - fired it up and still makes the noise.
Back to the drawing board
I'll look at things again tomorrow then prepare for head removal.
Last videos and then I will pull the head and you all can escape this saga for a while
First video sounds normal with an occasional random knock:
Second I rev a little to induce the knock, it just started when I accidently stopped the video:
Third video is the knock in all its glory:
Nasty, eh??
Head gasket etc en route. Engine rebuild is back on the table pending removal. Feel free to add any final suggestions.
Adding insult to injury, this is stuck in my head (at least it's period correct):
Is the cam lobe on #4 exhaust darker than the others? Don't see as much oil splash on that one also.
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It's tough to tell from the video, but can you slow the idle down and then tell if it is going the speed of the cam/valves or the speed of the engine? That might help pin point it.
Why didn't I think of that!I suspect @Markos can/will post a slow-motion video to illustrate the cadence.
You can go to "settings" in the last video and change the playback speed to .25. To me, it is clearly going with the valve train.
Maybe push hard on each rocker while the engine is running and see if you can find the offending one.
Slowing the video down is interesting. It does seem like it is on pace with the valve train and one of the exhaust valves is right in time with the knock. Reality is that a stethoscope (even long screwdriver or rod up to the ears) might help to pinpoint.
Damn bad luck Steve.