Wobble on Serpentine pulley

[rrwebster]

I recently purchased a 1983 Porsche 944, 5 speed.

There is a vibration around 1200 rpm so I looked around at the engine. The lower pulley that runs the alternator and air conditioner, the one attached to the crank looked out of round. I purchased another off of ebay, replaced it… checked it and it’s a little better but still looks out of round when running and the vibration is still there around 1200 rpm.

Did I install it incorrectly? If I remove it and look at the outer balance belt drive that it mounts to at idle it looks fine, not out of round. I see there are balance weights on the pulley… is there a trick to how it’s mounted?

Thanks in advance for any advise...

Robert

[porsche4life]

Check the motor mounts...

www.clarks-garage.com

[rrwebster]

I've looked at the passenger side motor mount.. it looks fine but then I don't really know what to look for. I do see the serpentine pully wobble...

[mikepellegrini]

Is the crank bolt torqued properly? (? 150-155 FtLbs?). Nothing inbetween the pullies and the gears?

When you had the pully off, if you laid it on a flat surface was it flat or warped?

If the pully was decently flat and not out of round, I'd think either there was something inbetween the pullies/gears that was preventing it from sucking all the way in flat, or that the assembly wasn't properly torqued.

If the pully was not flat, I'd buy a new (used) one.

[Rasta Monsta]

Yeah, that is weird. Bent crank (very unlikely) or install problem. I wonder if the bolt is bent? Woodruff key deformed? I needed to do some filing on the first couple I ever took out - DOH!

[rrwebster]

the pulley appears to be out of round.

I used a caliper on the old one and it looked like it's out of round by .015

here is a terrific link for 944 motor mounts. I guess I will try this before I do anything else with the balance belt.

Motor Mounts

is removing all the other things really necessary for the motor mount change?????