Wobbling Front Pulley 85 Carrera

[Downtownandy]

So about 2 weeks ago I started heard a funny noise at idle and opened the hood and saw nothing funny. Then on my drive from Texas to NC last week I opened the hood again and saw that the fan belt was a little bit loose. Finished the drive and then yesterday I heard the noise again and saw that the pulley appeared to be wobbling forward and backward (axially) about a 1/2". Then today my cousin and I looked at it and he was watching as a started it and noticed that the pulley is warped. Enough that it's beginning to rub the fan housing. Is all I need to do replace the pulley? (I'm a total Porsche noob, first 911)

1985 Porsche 911 Carrera Front Pulley warped. - YouTube

[DRACO A5OG]

Oh my Brother,

Your pulley bolt is loose, ask me how I know. It may have also compromised your crank shaft seal and/or worse the #8 bearing seal.

Here is my write up: Crankshaft Seal Club, just joined :-o fix on page 4




I feel your pain :-(

You may get lucky and just need to be torqued down.

Jim

[DRACO A5OG]

Welcome BTW, also it is the "rear" pulley :-(

[donagain1]

Actually, you didn't say specifically whether it was the pulley on the crankshaft (double pulley for A/C belt), or the fan pulley. The former is just as Draco describes, while the latter is a two-piece affair, with the outer half being much thinner and far less solid than the cast crankshaft pulley. It is secured with thin spacer washers and the fan nut on the end alternator shaft, and to my mind far more likely to come undone and wobble than the stout lower pulley would be to warp. Just a thought.

[DRACO A5OG]

Video shows the double pulley, it is pretty bad

[donagain1]

Oooh scheiser, I totally missed the video link. Arrgh, das ist nicht sehr gut!

[Downtownandy]

So a partial engine drop is required yes? Because that pulley is probably shot to **** by now? Especially after I just got done driving it over 1200 miles from Texas to NC.

When doing the engine drop do I really need to do all of the following?:

Disconnect Battery
Remove Fuel Pump Relay
Empty Oil from Engine Sump
Empty Oil from Oil Tank
Raise Car on Jack Stands
Disconnect Hard Oil Line
Disconnect & Remove Rubber Oil Line
Disconnect Clutch Cable, Arm, and Helper Spring Assembly
Disconnect Starter Solenoid Electrical Connections
Disconnect Reverse Backup Switch from Transmission
Disconnect Heater Hoses From Heat Exchangers
Disconnect and Remove Shift Coupler
Disconnect A/C Compressor and Tie to Side of Car
Disconnect all Fuel Lines
Disconnect Main Engine Wire Harness
Disconnect Breather Hoses
Disconnect Accelerator Linkage Bar
Disconnect Cruise Control Cable
Disconnect Oxygen Sensor
Remove Four Nuts that Hold Engine to Tranny
Remove Engine Motor Mount Bolts
Lower Engine Down
Pull Engine Away from Transmission
Lower Down onto Cart and Remove

[zippy_gg]

You probably don't need to separate the engine from the transmission, just loosen the transmission mounts.

[DRACO A5OG]

Disconnecting the battery, is always a good idea. There is that fuse box in the engine bay that loves errand tools touching it. But up to you Brother.

Just disconnect the shift coupler as not to damage it and the shirt rod into the trans. Honestly I did not disconnect it the second time around be I only went down 2-3". But if you jack slips it is history.

Just take you time, no need to rush this job.

J

[DRACO A5OG]

I would just do this for a partial drop/lowering:

Disconnect Battery
Raise Car on Jack Stands
Disconnect Shift Coupler
Remove Bumper & Muffller
Disconnect A/C Compressor and Tie to Side of Car
Remove Engine Motor Mount Bolts and cross member
Lower Engine Down on 2-4 inches NO MORE!

[zippy_gg]

Originally Posted by DRACO A5OG

I would just do this for a partial drop/lowering:

Disconnect Battery
Raise Car on Jack Stands
Disconnect Shift Coupler
Remove Bumper & Muffller
Disconnect A/C Compressor and Tie to Side of Car
Remove Engine Motor Mount Bolts and cross member
Lower Engine Down on 2-4 inches NO MORE!

Jim, would you also loosen the tranny mounts or is it not really necessary?

[DRACO A5OG]

Not needed, 2-4" has very little angle to the trans mounts from what I observed.

Removing the bumper and muffler actually gave me plenty of room even to hand grind down the mushroom pulley mount.

[zippy_gg]

Good to know, thanks!

[Downtownandy]

I would just do this for a partial drop/lowering:



Disconnect Battery

Raise Car on Jack Stands

Disconnect Shift Coupler

Remove Bumper & Muffller

Disconnect A/C Compressor and Tie to Side of Car

Remove Engine Motor Mount Bolts and cross member

Lower Engine Down on 2-4 inches NO MORE!

What about oil lines?

[Jim Sims]

If the engine was worked on previously and the crank pulley removed there is a good chance the pulley screw wasn't properly re-tightened. Some of the commonly used references specify too low a tightening torque for this screw. From another thread:

"In most of the early 911's prior to 1978 the crankshaft pulley screw was a M12x 1.5 x 22 mm long hex head plated cap screw of strength class 8.8 (PN 900.083.001.02) and it was used with a 12mm spring or wave washer (PN 900.028.014.01). This screw could only be tightened to 80 Nm or 59 ft-lbs due to it's strength class. This combination was used for both A/C and non-A/C equipped engines. A spring or wave washer is almost worthless as a fastener locking appliance so it is interesting to note that in the mid-year Turbo's and Carreras with A/C that the pulley screw changed to PN 999.093.005.02 (also M12x 1.5 x 22). This screw is of the "Durlok" form (http://www.franciskirk.com/screws.html) and is of strength class 12.9; this screw is tightened to 170 Nm or 125 ft-lbs (which is higher than a normal plated class 12.9 screw tightening torques of 140 Nm or 103 ft-lbs) due to the Durlok locking features consuming some of the tightening torque. A spring washer was not shown being used with this screw. Beginning in 1978 the spring washers were not being used on any of the pulleys but the pulley screw for all cars (through 1989) was the 999.093.005.02 part number.

If you received a Porsche part number screw 999.093.005.02 you have the correct part. The head likely has the number 12.9 embossed on it and under the head there may be serrations. A wave washer is not used with this type of screw. The extra number (22) in Wayne's book is the screw's length in mm. All of the pulley screws were 22 mm long (length is measured from the bottom of the head to the tip of the thread). Tighten to 125 ft-lbs (no lubricant on the threads).

Jim

[DRACO A5OG]

Originally Posted by Downtownandy

What about oil lines?

No worries, you will not be lowering enough to affect it. with the bumper and muffler off it should be plenty of room. Lowering it 2-4" just gives you a better view of it.

Just keep on everything as you lower, go slow and make sure it is secure.

[Downtownandy]

So the pulley came off, sheared the bolt. Luckily the seal is unscathed, but I'll replace it anyways. I guess the bolt probably was loose but I had not yet had an opportunity to drop the engine to get to it. Ordering the new bolt, pulley is en route, will fix her up this weekend.

[DRACO A5OG]

Cool, keep us posted ;-)

[Downtownandy]

Jim, in the picture of the crank in post #2 on this page, is that how clear of a view you had of the crank after removing the muffler and crossmember, etc? Because I'm going to need to drill a hole in what's left of the bolt in the crank to get an extractor on it. So I'm hoping that's how clear of a shot I'll have at it.

Here's a couple pics of how it's looking:
The groove that the pulley wore into the fan housing


The pulley:




Bad view but the crank shaft is smooth on the end, only concern is that the dowel pin might have slightly wallowed out the hole a very minute amount, can't tell yet.

[Tippy]

I had the crank bolt come loose too because the sorry ass Bentley manual I had, had the bolt torque to about half of what it really needs. I should have known better but I plainly didn't catch it when rebuilding the engine.

Torqued to spec and all is well. No damage to nose of crank or seal occurred.

Trust me, this thing was minutes to hours away of flying off the crank if I didn't see it in time.