knock knock... what's that?

[ivoryplayer]

Dave,
Thanks for the heads up. I found the gaskets and seals I need for around $200 total on I think bimmerspeciaties.com. I'll probably just stick with the timing chain set already on the "new" motor. As for the cooling system. I'll need to read up on that.

Barry

[cpatstone]

Here's the video of my car and the as-of-yet mystery knock. And before there's any hazing, the right fender liner was rattling around... you'll see...
http://www.youtube.com/watch?v=98E4JnTs6aM

other updates:
* haven't drained the oil yet.
* apparently I don't have the oil filter cap remover tool.
* oil level is good, oil looks and smells good, no particulate on the dipstick.
* coolant level was low, but there was coolant present. (paging Gimp - when was it full?)
* All spark plugs looked pretty normal, and all were consistent.
* just a little milky junk under the oil fill cap after I ran the motor for a few minutes. Could be condensation mixing with the oil - it's cold here.
* I did smell some coolant in the cabin on the ride up from MD. Could be leaking from somewhere in the engine compartment, or could be the heater core?

Thanks for the help!

[gimp]

Originally Posted by cpatstone

* coolant level was low, but there was coolant present. (paging Gimp - when was it full?)
* All spark plugs looked pretty normal, and all were consistent.
* just a little milky junk under the oil fill cap after I ran the motor for a few minutes. Could be condensation mixing with the oil - it's cold here.
* I did smell some coolant in the cabin on the ride up from MD. Could be leaking from somewhere in the engine compartment, or could be the heater core?

Thanks for the help!

Last time I even looked at the coolant was when I replaced the radiator. It may be possible that I bled it and didn't get it full. When the radiator blew, it spewed coolant EVERYWHERE. Normal, day to day driving, I never noticed a coolant smell, but on long drives I would occasionally catch a wiff - I had assumed it was just coolant that didn't get cleaned up that had dried and the smell would come back.

The milky junk is new to me. I didn't notice anything like it when I changed the oil two-ish weeks ago.

[budget76]

From the video it sounds like it's in the top end of the motor, so that would rule out the crank bearings. Kind of irrelevant since you found a new motor. I'm interested to see what you find when/if you pull it apart.

M44's don't have a vanos setup, correct? IIRC that's what my shot vanos sounded like when I got the revs up on the motor, been a while since then though I could be remembering wrong.

[cpatstone]

Originally Posted by budget76

From the video it sounds like it's in the top end of the motor, so that would rule out the crank bearings. Kind of irrelevant since you found a new motor. I'm interested to see what you find when/if you pull it apart.

M44's don't have a vanos setup, correct? IIRC that's what my shot vanos sounded like when I got the revs up on the motor, been a while since then though I could be remembering wrong.

I think it was ivoryplayer who needed and found a new motor. I haven't quite given up on mine yet. M44s don't have vanos. I couldn't find anything wrong under the valve cover... so I'm still at a loss. ???

[ivoryplayer]

Originally Posted by cpatstone

I think it was ivoryplayer who needed and found a new motor. I haven't quite given up on mine yet. M44s don't have vanos. I couldn't find anything wrong under the valve cover... so I'm still at a loss. ???

Could it be a valve sticking maybe? Mine soundes exactly the same as yours does which is why we thought it spun a bearing. I'm gonna be really not happy if I'm changing my motor over nothing. Haven't pulled my old one out yet.

[cooljess76]

What gets me is that it's only present at higher rpms. If it was a rod bearing or sticky valve it should be a constant ticking. I've never heard of these motors having lifter problems. Did you say that you removed the valve cover? I kinda suspect that it's not rpm related but maybe pressure related. It's pretty difficult to check on our cars because the exhaust manifold sits so close to the chassis, but I'd check for leaks or cracks around the exhaust manifold. Again, you might not feel anything leaking until a certain rpm, so this would make it even more difficult.

[bazar01]

That is not a crank bearing or rod knock.
It is not a bad lifter tick either
It sounds more like at higher RPM, the piston is hitting a valve, might be a broken valve spring.

[xxxJohnBoyxxx]

Ok here is my opinion. That is valve-train related. I say this because the noise is half the rpm of the engine which is what the camshafts RPM is.

I bet if you remove the valve cover again and turn the motor over by hand with a socket you will find your issue. If not when rotating by hand then remove camshafts and check each rocker arm for a roller that has lots of play and all parts for your issue. I'm fairly confident it's in your valve train. If it is a broken spring I know how to change them without removing the head

Your motor is running too good at idle and upper RPM to have bend valves or any valve contact, if the valve was sticking you would have a pop in the intake or exhaust when that cylinder fired. The motor would stumble bad on a intake pop and you would hear the exhaust pop.

Some issues that this could be are (in order of what I think it is): Weak hydralic lifter, bad roller on rocker arm, bent/cracked rocker arm, broken valve spring, massive worn valve guide (highly doubt due to engines good idle), camshaft end play issue (highly doubt since all valves would be effected), loose camshaft cap bolts (highly doubt). Could be something I didn't list.

If you pull the valve cover and take some macro pictures real close up some of the board members might be able to see the issue if you can't find it

Best of luck, John S

[budget76]

Originally Posted by cpatstone

I think it was ivoryplayer who needed and found a new motor. I haven't quite given up on mine yet. M44s don't have vanos. I couldn't find anything wrong under the valve cover... so I'm still at a loss. ???

Guess I should read the screen names instead of skimming during my study break

I'm going to x3 the valve train. I wanted to say it was a piston-valve contact, but it sounded so smooth I doubted that. My first guess now, though, would definitely be a either sticky or dead lifter like John said. Just watched my old videos of a sticky lifter though, and it was present at all RPM's, easily distinguishable at idle

GL with the diagnostic, I'd say pulling the valve cover and taking a closer look is going to be the next step.

[gimp]

Fingers crossed it's valve train (even though that means it probably would have been cheaper for me to fix!)

I was staring to think broken valve spring last night as well. I would def. pull the cover and turn the motor over by hand.

[xxxJohnBoyxxx]

Originally Posted by budget76

Guess I should read the screen names instead of skimming during my study break

I'm going to x3 the valve train. I wanted to say it was a piston-valve contact, but it sounded so smooth I doubted that. My first guess now, though, would definitely be a either sticky or dead lifter like John said. Just watched my old videos of a sticky lifter though, and it was present at all RPM's, easily distinguishable at idle

GL with the diagnostic, I'd say pulling the valve cover and taking a closer look is going to be the next step.

It is odd and seldom but at idle and low RPM a rocker that stays on the valve stem and has a collapsed lifter with some oil left in it to cushion the tap and oil on the rocker lifter surface will make a little noise. When you bump up the RPM's the valve throws the rocker off the valve stem and then you get that very loud tap from the larger clearance from that collapsed lifter.

Only my theory if you find a bad lifter.

John S

[bazar01]

Just pull the valve cover off, push on the rocker one at a time and see if one will move down more than the other with the same force, then it's a broken valve spring.
Collapsed lifter makes a constant ticking noise and this is not it.

[xxxJohnBoyxxx]

Originally Posted by bazar01

Just pull the valve cover off, push on the rocker one at a time and see if one will move down more than the other with the same force, then it's a broken valve spring.
Collapsed lifter makes a constant ticking noise and this is not it.

cpatstone ~ When you are looking for your weak/collapsed lifter do not just start pushing on one lifter then start on the next. You need to be sure you are on the compression stroke for the specific cylinder you are working on, then check all 4 lifters/springs/rollers for that specific cylinder, rotate motor and start the next cylinder. It is easy to confuse the compression stroke with the overlap stroke.

Overlap is when the piston is top dead center but the camshaft has both intake & exhaust valves open a tiny bit to cause scavenging to help pull the intake charge into the combustion chamber.

Best way to ensure your on the compression stroke is to make sure both intake & exhaust camshaft lobes highest lift point is 180 degrees from the roller on the rocker arm and lowest point on the camshaft lobe profile is on the roller.

You might have already known this but I wanted to put this out there just incase.

John Smith

[cpatstone]

Originally Posted by xxxJohnBoyxxx

cpatstone ~ When you are looking for your weak/collapsed lifter do not just start pushing on one lifter then start on the next. You need to be sure you are on the compression stroke for the specific cylinder you are working on, then check all 4 lifters/springs/rollers for that specific cylinder, rotate motor and start the next cylinder. It is easy to confuse the compression stroke with the overlap stroke.

Overlap is when the piston is top dead center but the camshaft has both intake & exhaust valves open a tiny bit to cause scavenging to help pull the intake charge into the combustion chamber.

Best way to ensure your on the compression stroke is to make sure both intake & exhaust camshaft lobes highest lift point is 180 degrees from the roller on the rocker arm and lowest point on the camshaft lobe profile is on the roller.

You might have already known this but I wanted to put this out there just incase.

John Smith

I didn't know that specifically, especially re: scavenging. Thanks! In fact I was just reading that the M44 is in fact an interference motor.

When I had the valve cover off, I didn't even consider pushing on the springs/rockers. Figured it would take way more than hand pressure.

I did look at all of the springs and didn't see anything broken.