rando part on garage floor

[Joesprocket]

Finished replacing the water pump and fired up the engine. Finally, success. Walk around the front of the car and find this on the garage floor. Shined a flash light all around and can't find where it came from. I wanted to drive the car to fully test the new pump but figured I'd play it safe and ID this part in the event I'd harm something if driven with a missing / broken part. Little help would be great.

 

 

[echappe]

alternator bracket grommet

[FunElan]

Yup. Put a urethane one in.

[Joesprocket]

this makes a lot of sense considering I've had the alt out twice in replacing the WP. and may also account for the engine shake on my car? I know M10's are known for this anyways. Time to do some diggin on FAQ.  Thanks gents.

[wegweiser]

Looks more like an air pump or A/C compressor bushing to me at least. I think alternator bushings are thinner, between metal tube insert and outer diameter. 

 

Check to see if the alternator is tight (fore and aft especially) and check for movement in air pump or AC comp, if so equipped. 

[ray_]

I agree with Paul, so far

[johnsboyd]

Vote for Alternator bushing. Agree to replace with urethane ones. Avoid the kinky alt..

Edited February 14, 2018 by johnsboyd

[stone02]

your car had an air pump on it long ago.

that bushing is from the metal bracket that is

most likely on the car still. under the battery

tray. if it is not there then that bushing fell into

the top of the frame rail and then finally fell

onto the floor. alt bushings are indeed very

thin walled. a loose alternator is a different

problem.

stone

[johnsboyd]

As for engine shake check the motor mounts. The driver side one is prone to failure when they get old. Grab the engine from the passenger side, if the mount is broken the engine will move a lot. 

Just a guess though! Could be a lot of things.. I replaced several dozen MM over the years when I was a bmw mechanic..good luck!

[Joesprocket]

Closing this one out. @wegweiser is right. I just pulled the alternator and all bushings are sound and in great shape.

While i was waiting for my new water pump in the mail i got antsy and pulled the air pump which was doing absolutely nothing considering a PO de-smogged the car but left all the hard core gear. probably in the event someone needed to quickly hook it back up. Even though i removed the bracket as well with the air pump it must of been loose somewhere or came off during removal and i missed it falling.

 

i think i'm in the clear! 

 

[Joesprocket]

9 minutes ago, johnsboyd said:

As for engine shake check the motor mounts. The driver side one is prone to failure when they get old. Grab the engine from the passenger side, if the mount is broken the engine will move a lot. 

Just a guess though! Could be a lot of things.. I replaced several dozen MM over the years when I was a bmw mechanic..good luck!

 

I've been thinking mounts too but when i checked them last i was under the car they looked in good shape. no cracks or rot.

the engine is probably most shakey as it's warming up but once its at temp it evens out.  I suspect most folks on here experience this as i've seen people mention a few times around here.

[johnsboyd]

Yea, if that’s the case it’s probably a carb thing related to warmup. 

[wegweiser]

If the motor mounts check out (no deformation, etc) then you might try adjusting your choke mechanism to offer a slightly higher idle speed / richer fuel mixture during warm up.

 

I find it physically painful to watch and listen,  as cold engined sports cars lope at cold idle, due to incorrect choke adjustment, or (in the case of side drafts) the driver being too inattentive to keep their toe on the throttle for a few minutes longer.

[golf73]

1 hour ago, Joesprocket said:

 

I've been thinking mounts too but when i checked them last i was under the car they looked in good shape. no cracks or rot.

the engine is probably most shakey as it's warming up but once its at temp it evens out.  I suspect most folks on here experience this as i've seen people mention a few times around here.

 

sometimes it's not the mount itself but where it mounts on the subframe that is cracked and needs to be welded and/or reinforced

['76mintgrün'02]

yep, the mount's mount.