Need BF.C's collective help on my rattle issue

[NOTORIOUS VR]

As some might know (or not know depending on who followed my build thread), the last time I had my motor apart for the HG when I put it back together it developed some sort of rattle noise in the head area.. The only thing that changed in the head was the addition of Supertech springs and retainers. The noise wasn't there initially but rather started 30-45 min after the first start when I was bleeding the cooling system and revving it.

It sounds like it is coming from the front of the head right at the top... very possible from the intake cam gear area but it's really hard to tell.

When I built the motor, all guides and chains were replaced as well as the lower tensioner (in the front cover).

After the rattle started, and hearing where the noise was I thought maybe the upper tensioner was failing so I bought a new one, after installing nothing changed and the noise was still there.

Then I thought maybe it was the VANOS unit, so I got another VANOS and rebuilt it with the Bessian Kit and installed it... same noise..

This weekend I took everything apart and redid the timing once again, thinking maybe I made a mistake somewhere somehow trying to set the timing. But once again I have the rattle noise.

I'm really at a loss here, it certainly sounds like it is coming from the top of the cam area right at the front of the head, the rattle happens when I start the car when the engine and oil temps are up to normal temp after the engine catches and the rev's fall back from 2k.... and I can make it rattle by revving the engine and holding it between 1500-2000 rpm... it also rattles on decel in that RPM zone. When the engine is cold it's almost impossible to hear the rattle.

It sounds horrible, the rattle/groaning it makes... Oddly enough the car runs great and I've put a few thousand KM on it (not being nice) with no real ill effects from what I can tell but the noise still worries me

HDI5xz7.jpg

[flyfishvt]

Check the stupid stuff first. Is it coming from that baffle plate on the hole for the oil cap? Is it the plastic cover on the intake cam? Assuming it's an m/s52.

[NOTORIOUS VR]

Check the stupid stuff first. Is it coming from that baffle plate on the hole for the oil cap? Is it the plastic cover on the intake cam? Assuming it's an m/s52.

None of that was interfering with anything that I could see when I had it all apart yesterday.

Yes it's an M52.

[rajicase]

I might have had the same issue with my old engine, it only happened when warm and it only happened when I revved the engine past 2k. And it only made the sound for a brief period of time; as it was passing 2k under accel and deccel. It wasn't your typical rattle, it was more of a high pitched buzz/groan. And it sounded like it was coming from the intake cam/intake manifold area. I chased it forever, new chains, new tensioners, new cam hardware/washers/spring plate, new/rebuilt vanos, checked the torque of the cams, etc... Tried everything to no avail. Found one other guy with a vid of the exact same issue, and he too, chased it forever with no solution.

I never fixed it, but I did swap engines. I now have a new bottom end BUT the same head, same tenisoners, same vanos, same supertech dual valve springs, same cams, etc...... and the noise does not happen on my current engine.

[NOTORIOUS VR]

I might have had the same issue with my old engine, it only happened when warm and it only happened when I revved the engine past 2k. And it only made the sound for a brief period of time; as it was passing 2k under accel and deccel. It wasn't your typical rattle, it was more of a high pitched buzz/groan. And it sounded like it was coming from the intake cam/intake manifold area. I chased it forever, new chains, new tensioners, new cam hardware/washers/spring plate, new/rebuilt vanos, checked the torque of the cams, etc... Tried everything to no avail. Found one other guy with a vid of the exact same issue, and he too, chased it forever with no solution.

I never fixed it, but I did swap engines. I now have a new bottom end BUT the same head, same tenisoners, same vanos, same supertech dual valve springs, same cams, etc...... and the noise does not happen on my current engine.

Well that is very interesting... Now I wonder if I should expand my search to maybe include the waterpump, etc. It's certainly not a bottom end noise and swapping the bottom end is not a possibility (it's a built motor).

[rajicase]

Well that is very interesting... Now I wonder if I should expand my search to maybe include the waterpump, etc. It's certainly not a bottom end noise and swapping the bottom end is not a possibility (it's a built motor).

Right, it definitely wasn't a bottom end noise for me either. The noise did stop, however, when I swapped the bottom end in. I have no idea why. Water pump was the same from my old engine. Swapped it onto the new one. I gave up and just assumed it was some weird harmonics. I beat on that old engine religiously and relentlessly with no ill effects, but it was an obnoxious sound.... Wish I had more to offer than I do, as I know the frustration here... I chased that noise for so long, pissed me off.

[beeasy]

For what its worth, I would try and see if the noise is duplicated with the drive belt off. Make sure its not coming from one of your accessories or pulleys. I had a rod knock noise one time that ended up being a loose water pump pulley. The bolts had backed out about a 1/4 turn each.

[NOTORIOUS VR]

Right, it definitely wasn't a bottom end noise for me either. The noise did stop, however, when I swapped the bottom end in. I have no idea why. Water pump was the same from my old engine. Swapped it onto the new one. I gave up and just assumed it was some weird harmonics. I beat on that old engine religiously and relentlessly with no ill effects, but it was an obnoxious sound.... Wish I had more to offer than I do, as I know the frustration here... I chased that noise for so long, pissed me off.

Yes very annoying (and kinda scary) for the most part. The noise being so prominent in the front of the head I keep coming back to something there. Sounds like to travel, but it's like its right there and really the only thing I haven't changed there yet is the VANOS spring/shim/washer that goes between the plates/cam gear

For what its worth, I would try and see if the noise is duplicated with the drive belt off. Make sure its not coming from one of your accessories or pulleys. I had a rod knock noise one time that ended up being a loose water pump pulley. The bolts had backed out about a 1/4 turn each.

That is a good idea and quite easy to do as well. I'll give that a try. Just another thing to tick off the list of possibilities anyway.

[BlackHawkRacing]

Can you grab a video of said noise?

[NOTORIOUS VR]

Can you grab a video of said noise?

I will certainly try, but with all the other noises under the hood from what I remember it's hard to capture that noise on camera.

[chikinhed]

Jackermac had the same issue. I welded up a hole in his front cover that the timing chain had made recently. Maybe give him a shout to see if that fixed the noises.

Sent from my GTX3582R

[NOTORIOUS VR]

Jackermac had the same issue. I welded up a hole in his front cover that the timing chain had made recently. Maybe give him a shout to see if that fixed the noises.

Sent from my GTX3582R

Gah... I wish someone made a clear valve cover

[NOTORIOUS VR]

FWIW, I've been doing more digging/reading/searching.. and it might be the intake cam disks and spring (part no 11, 10 and 9 in my diagram in the OP), although from the threads I read they were early M50 guys who didn't have that spring setup to begin with, so who knows. I'm not sure why it would just go bad on me to begin with though.

Found a video of an S52 that is quiet enough for you to hear the noise (mine sounds just about like that):


Links to threads I've found so far:

http://www.bimmerforums.com/forum/sh...(S52)-Thoughts
http://www.bimmerforums.com/forum/sh...after-s50-cams
http://forums.pelicanparts.com/101-p...cam-m50tu.html

[iRodD]

That sounds really familiar. I'm gonna say vanos shaft assembly.

[rajicase]

Hope you figure it out.. still bugs me to this day.

I replaced the spring plate and thrust washers on the intake cam, didn't fix it for me. Vanos didn't do it for me either(both rebuilt and swapped units).

[cj.surr]

Yeah I've got the same noise after putting my S52 back together. I used a cheaper bearing for the vanos that I found on ebay. Using a stethoscope, it is definitely coming from the vanos unit. I would do the same evaluation on yours.

[chikinhed]

I think that some people change the intake sprocket but don't change the mating worn cam gear which can also cause noise.

In Jakers case he had a lower chain guide fail which lead to a hole in the front cover. His car made all kinds of strange noises from the Vanos area.

Sent from my GTX3582R

[rajicase]

Yeah I've got the same noise after putting my S52 back together. I used a cheaper bearing for the vanos that I found on ebay. Using a stethoscope, it is definitely coming from the vanos unit. I would do the same evaluation on yours.

Ahhhh this reminded me. The one thing that changed from my old engine's head to this one was the vanos shim. I had shimmed my vanos for use with big cams and removed the shim when I went back to stock cams and turbo. Maybe when I took the vanos apart the first time I put it back together incorrectly... Hmmm

[NOTORIOUS VR]

All good points, but I have an incredibly hard time believing that both of my VANOS units went bad in the exact same way, and the new/2nd one having the exact same symptom as the 1st even after a fresh rebuild.

ie. 1st/original VANOS unit (which was rebuilt w/ Bessian kit) was working until the head came off and went back on for the HG replacement. Get a 2nd VANOS unit, rebuild completely again w/ Bessian kit (completely as was the first) and from the minute it went it the same exact noise was there still.

So you can understand that it's very, very unlikely that both VANOS units have identical issues in this case. At least IMO.

I suppose one thing I could do is cut away an opening of a metal valve cover and glue some lexan over to seal it back up so I can look inside while the engine is running. My buddy has a spare OBD 1 VC I should be able to use.

[someguy2800]

the m50 vanos motors do not have the spring. They just have two plates with the sprocket riding between them with a tight clearance. I have a spare one sitting on my shelf if you want to try it.

http://www.realoem.com/bmw/enUS/show...diagId=11_1541

If it were me I would try swapping to the m50 plate setup and if that didn't change anything I would try locking the intake cam by replacing stud #6 with M7 bolts and running it without the vanos unit.

[dburt86]

does it do it with the vanos off/disconnected?

[NOTORIOUS VR]

the m50 vanos motors do not have the spring. They just have two plates with the sprocket riding between them with a tight clearance. I have a spare one sitting on my shelf if you want to try it.

http://www.realoem.com/bmw/enUS/show...diagId=11_1541

If it were me I would try swapping to the m50 plate setup and if that didn't change anything I would try locking the intake cam by replacing stud #6 with M7 bolts and running it without the vanos unit.

Running w/o VANOS could be a good idea for sure... Certainly it seems like the later VANOS setup that I already have is superior and people have reported it is a fix for rattling. Still all good ideas... Not sure how many times I have get myself to pull apart this stupid thing before I go crazy, but I guess I will find out soon enough

does it do it with the vanos off/disconnected?

Yes. The noise is most prominent w/ the VANOS deactivated.

Interestingly if I force the VANOS to be on all the time (from idle) the noise/rattle is less (going from memory, as I tried this as a test when when the rattle first started on the night of the coolant bleeding) noticeable.

FWIW I also verified oil pressure right away that night everything was in check, and have since put an Oil pressure gauge in my car as well.. No issues there. Just stating for completeness.

[iRodD]

All good points, but I have an incredibly hard time believing that both of my VANOS units went bad in the exact same way, and the new/2nd one having the exact same symptom as the 1st even after a fresh rebuild.

ie. 1st/original VANOS unit (which was rebuilt w/ Bessian kit) was working until the head came off and went back on for the HG replacement. Get a 2nd VANOS unit, rebuild completely again w/ Bessian kit (completely as was the first) and from the minute it went it the same exact noise was there still.

So you can understand that it's very, very unlikely that both VANOS units have identical issues in this case. At least IMO.

I suppose one thing I could do is cut away an opening of a metal valve cover and glue some lexan over to seal it back up so I can look inside while the engine is running. My buddy has a spare OBD 1 VC I should be able to use.

Its not that the vanos went bad. There is something just not meshing right.

[dburt86]

is it possible to run the car with a non vanos front plate?

I try not to bore myself with these peasant 6 cylinder engines

LOL jk

[NOTORIOUS VR]

6 cyl problems... Am I right?

Its not that the vanos went bad. There is something just not meshing right.

Interesting point of view... although I have to wonder why it just decided not to mesh one day but was fine for thousands of KM before?