Does rod knock get louder with higher revs?

Stevehose said:
I found a trick to getting the bleeding going is to loosen the 19mm cap on its threads a little, start pumping with the long screwdriver, when oil starts to pass the threads then tighten the cap and keep going until it’s firmed up. If you shake a clean new piston you should be able to hear the bb rattle inside.
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I tried that. It helped. I found when I tightened the cap it squeezed more air out. So I loosened the cap to draw oil past piston and then tightened to force more bubbles out and so forth.
 

To see if I could isolate the sound I ran the engine without the valve cover….

If the knocking noise is due to chain slap wouldn’t I hear it through the stethoscope if I hold it against the upper cover or other similar location? I just hear whirring but no knocking or tapping sound.
 
Skiver said:
No noise comes back after a while. Its loudest between cylinders 2 & 3 now. I’m going to run again with valve cover off after it’s warmed up a bit. There’s no sound when cold start up
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Better have a plan for all the oil that’s gonna spray out of there with the valve cover off
 
The video is awesome!

no splashing
should that worry us?
 
Steve - the chain and gear aren’t slinging oil?
 
Skiver said:
put all the belts back and knocking sound comes back.
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This implies your knocking sound only happens with belts installed. If car runs smoothly and no knock with belts off then it strongly suggests you have a failing accessory drive component (water pump bearing, fan clutch loose, failing alternator bearing …).

Sorry I’m late to the thread and perhaps you’ve already found the culprit.

IMHE, rod knock gets louder/harder under load; is not always accompanied by low OP; often smooths out with higher rpm.
 
JFENG said:
This implies your knocking sound only happens with belts installed. If car runs smoothly and no knock with belts off then it strongly suggests you have a failing accessory drive component (water pump bearing, fan clutch loose, failing alternator bearing …).

Sorry I’m late to the thread and perhaps you’ve already found the culprit.

IMHE, rod knock gets louder/harder under load; is not always accompanied by low OP; often smooths out with higher rpm.
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Still haven’t found the culprit. Still. knocking once warmed up. Got a longer screwdriver and cleaned the tension piston and re-primed.
Secondary question - I tapped into the fuel line before the rail. Fuel pressure is 20 psi. Manual suggests 3psi?
 
Interesting thread. D-jet fuel pressure is 29psi. 3psi is for carbs, if I’m not mistaken. Yours need adjustment on the regulator under the plenum. But it’s not the problem you’re looking for.
 
Quick update - took the car to a classic car mechanic. He says most likely piston pin is loose or worn
 
Did the added piston bleeding increase the compression pressure as indicated by Don?
There has been a report of recent production Schaeffer tensioner piston coming with an internal spring between the ball and rail port making bleeding most difficult/ineffective. Shop that found it took apart and removed "added" spring. BMW may be sourcing from same production?
Have contacted Schaeffer but only a "redirecting my inquiry" response so far.
 
Rick,
Did you purchase all the pistons from BMW or elsewhere? INA/Schaeffller brand or other branding?
 
All INA from a known BMW parts store I haven't taken the ball and spring out, that would have been my next move I used a good used one as I did not have the time to screw around Did your guy leave the ball in and just removed the spring?

Thanks, Rick
 
Sorry I should have been clearer - it’s wrist pin - holding connecting rod to piston head that is likely worn
 
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