mikegnx

I bought a 1982 Porsche 928, I would like to remove the AC compressor, is there a bypass pulley available or can I just remove it considering it has an independent belt?

Speedtoys

Leave it, or find a pulley.

Dont side load the crank by just pullings things out because you think weight makes a difference.

mikegnx

I'm looking for a bypass pulley does it exist? if it does where can I find one? I don't think removing the compressor should cause any stress on the crank.

jeff spahn

Just make one. Take a bit of work but you could fabricate one. Be easier to leave it.

Ducman82

why would you need a bypass pulley, just leave it off?

mikegnx

Thanks guys, sounds good, I'll remove it.

The Forgotten On

The compressor belt has quite a bit of tension on it. I really wouldn't want to risk cracking the nose of the crank off.

Mrmerlin

As others have also mentioned,
if you look at the way the belts are positioned,
they offer a side load to the crank snout,

IOW the loading is pretty even to cancel each other out.

NOTE with the air pump and AC compressor removed,
then the pull will come from one side.

if your belts are really tight this can side load the crank snout,
and transfer into the front main bearing.
Take apart a girdle and look at the front main bearing to see how it wears from lack of belts, or tight belts

Koenig-Specials 928

I don't think he's listening guys.
He's bent on removing it so leave him alone

928nut

I've removed mine 10 years ago and never looked back. Gee, nothing had blown up yet. I'll report when it does ;-)

mikegnx

The smog pump is on the left which I need for emissions inspection and the alternator and power steering are on the right, of the four wouldn't the A/C be the most taxing. It is possible that serious stress on a crank can cause premature wear on front bearings. I am a 87 GN guy, 1st Porsche project and liking it, thanks for the info!

Speedtoys

Balance out the pull of accessories on the other side of the crankshaft.

Bearings are important to you, right?

Lizard928

So the more or less constant downward force of the running engine is of no concern, but the load from the accessories on just the one side will most certainly overcome the shear factor on the bearings, got it!

Speedtoys

You mean that counterweight balanced, per-main momentary and engineered-for force, not the constant force at all times, including parked?

That force?

Lizard928

Just so I am understanding you on this,
Because it is counterweighted and balanced means that it does not exert any downward pressure, even when parked?

Or how about the multitude of SC cars who have a much larger belt, with a much higher tension than any of our stock accessories run? Because of this, how many miles should SCed cars go before they tear down and install new front mains? Are you going to be replacing yours before you install Hans's SC setup?

The reality is that no one has any definitive proof that running accessories off one side of the crank causes any damage to the bearings on our engines. In fact all the newer single serpentine engines have pull from only one direction. There is no issues with them....

You will see much more damage to the bearings if you run garbage oil, don't change your oil often enough, track your car, the list goes on.

There are numerous people on here, myself included who have run 928 engines for long periods of time without the AC or smog pump belts on. None of us have seen any adverse side effects. I pulled one engine apart that I had done this with for probably 5+ years. There was zero abnormal wear from other engines that I have disassembled.