strange noise from front of motor at around 2800 rpm

[ddb]

poorsche1,

If your car has a manual transmission it has an alternator pulley clutch that rotates freely in one direction only. You shouldn't try to rotate it in the other direction because it could cause damage.

A while back I experienced an odd noise that turned out to be my alternator clutch pulley going bad. It happened right after I installed a new water pump and a whole bunch of other parts so I already had my access panel off. It was rather easy to hear that the noise was coming from my alternator.

I would describe the noise differently from your description, but that doesn't mean it isn't the same problem. In my case it was obvious from idle. If you've ever heard an automobile AC compressor cycling on and off frequently due to low freon, my clutch pulley noise was similar.

Here is a thread I started when I experienced my problem.

Best of luck,

ddb

http://www.986forum.com/forums/showthread.php?t=21779

[poorsche1]

looked up your thread, you are right not the same sound, but what is crazy is that i bought the alternator tool you have pictured at a swap meet for 5 bucks a while ago. when i bought it i didnt know what it was for and the guy i bought it from didn't know what it was for either, i bought it because it looked cool. when i saw the pic i went to my toolbox and sure enough there it was. hope i never have to use it.
well as for the brokster, all the pulleys, spin fine, sound ok, and no play to speak of, but i did notice that the AC pulley when i try to twist it up and down does have slight movement which i am not sure if it is normal. i bought a mechanic stethescope and will put belt on tomorrow and try to hear where noise is from.

[poorsche1]

not good news today, i spent almost an hour and a half trying to single out a pulley by spraying WD 40 and listening with a stethoscope but couldn't single out a pulley. i finally pulled off the belt to try one last time with no belt and i heard it. at 3000 rpm you hear a clattering sound at 3000 rpm. the other night with the belt off i didn't hear it but today heard plain as day with the belt off wondering if it can be a collapsed lifter or a chain tensioner or a chain guide broken. I already changed the ims bearing about 2000 miles ago to the LN Engineering ims bearing. at that time the rear main seal sprung a big leak so while changing that i decided to change the intermediate shaft bearing, glad i did because it had already lost all its grease and the balls looked scored and it didn't spin smoothly at all. the motor has 42000 miles on it. now what?

[RandallNeighbour]

If I were you I'd call Jake. He'll give you the best advice on this forum.

[poorsche1]

ENGINE CLATTER
FINALLY FIGURED OUT HOW TO UPLOAD A VIDEO. you can barely hear the clatter on the video it is more a clatter.to me it sounds more like loose chains clattering. can the tensioner break or get weak and let the chain smack the case at a certain rpm? can the chain guides break? or is there something else that will make a clattering sound like that?

[jdiba]

Poorsche1, you find out what the issue was yet ??

[poorsche1]

been slow working on her due to time cosuming work project. but have managed to do the following so far
removed the belt to make sure it was not one of the pulleys-- noise was still there at 3000rpm
drained the oil--found nothing
cut the oil filter apart -- found a few really small pieces of brown plastic ( about 1/16" in diameter)
dropped the oil pan to see if larger pieces in bottom-- found nothing

put it back together put car on trailer and took it to a porsche mechanic friend of mine to hear the noise. he sais it is ims bearing or a bad tensioner.

about 2000 miles ago i replaced the ims bearing with a LN Engineering bearing and do not think it could have gone bad. so i will purchase the tensioners and swap them as soon as i can get a break in my schedule. will keep you posted