[jolbrich]

Hello all, my alternator/ac compressor belt broke the other day and I had a new installed. after about 2 days it started squealing like a well you know. I took it back to retighten which they did by removing the under covers and tightening this bar. Well I have been driving pretty regurarly for about two weeks now, and it is stating to squeal again for the first 5 minutes or so upon start up. Soooo my question is has anybody else experienced this, and are there special instructions for adjusting this belt and keeping it tight.

Thanks in advance,

Jason

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[rl968]

Are you sure you have the right size belt? I had this problem on my 86 911, difference of a half inch in size will make a big difference..

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[jolbrich]

Thanks for your reply, I am going to have to check.I will go online to see what the exact specs are for belt. they looked it up at the shop, and put the new one on brought in from another shop. Never thought to think it could be wrong belt.
So to your knowledge nothing special about intalling and tighteneng that specific belt.

Jason

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[flash]

are you sure the mounting points of the compressor are intact and tight? the ear of the compressor is known to break, usually due to failure to loosen the bolts prior to adjustment, and/or failure to tighten afterward

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[rl968]

Looking it up is not good enough if you they didn't use the porsche part data base. If you go to an auto parts store and tell them you need a belt for a porsche 968 1993, it will show up in their database, but several might be listed and you have to know to pick the right one.

For example, here is Pelican's page for the belt. Notice they have two, one from conti and one direct from porsche, which costs twice as much. I'd buy the porsche brand belt. This may not be your problem, but for me in my 911 it was. Also, some belts are shaped differently, v-groove vs flat and this can affect how it is designed to seat on the pulley's.

http://www.pelicanparts.com/cgi-bin/smart/...95%29%2C%20Each

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[flash]

hmmm - i went to that page, and they only list one, and it's the conti, and they say it's "a porsche supplier"

it's hysterical that people choose something because it's the "porsche" part - conti was the "porsche" belt for a while - it changes year to year, based on the pricing porsche gets from a manufacturer - the belts all meet the specs, but those specs are pretty loose

i'm pretty sure the original was dayco (though it could have been gates)

that being said, i would not buy conti - in my own experience, they stretch and break

gates all the way for me

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[Lear35A]

To properly set the belt tension you need to use the Porsche tension measuring tool. The spec is 9.5 plus one turn for the A/C. It is quite tight! Two mounting bolts must be loosened on the A/C compressor, then the adjusting bar rotated to get the proper tension, and then the two mounting bolts must be retightened. Of course the lock nuts on the adjusting bar must be tightened too. Miss any of these things and problems are probable.

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[flash]

that's one of the reasons i put together the tensioner kit - it takes some of the tension off of the tensioner, and adds heim joints so things move more freely, alleviating some of the bind-up that causes problems

you still have to loosen the mounting bolts before adjusting, and you still have to tighten them, but there is less tension on the belt required, and things just line up better

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[jolbrich]

FRom what I can gather from you all is that the mechanic did not tighten properly. all he did was adjust the the tension bar. Nothing with ac compressor bolts. So it looks like the proper steps may solve the problem. I will give it a try tomorrow.

On another note what are your opionions on the the front underskirting. I have heard some refer to as the "batwing". Do they serve a real purpose. I find it them more of an annoyance as they have to be removed to really address and motor, belt issues. Anyone running with out them?

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[flash]

YES!!!

it is incredibly important that you run all of the underbody panels (front apron, engine tray, and 3rd tray if you have it) - contrary to what you might think, you need to prevent extraneous air from entering the engine bay - this promotes cooling efficiency - when you remove them, the negative pressure behind the radiator is decreased, and thus the system does not cool as well

they deleted the 3rd tray in later models, but it does help

i know it's a pain - believe me, as i've had mine off at least 2 dozen times in the last year - but, they really make a difference

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[rl968]

Flash, there are two listed on that page, look to the left of the page where it says other brands available.

+1 on the Gates recommendation, that's what I have on my 911.

Are you sure about the cooling aspect of the underbody trays? I haven't had them in (my car has two of them), I've had the car to the track and I don't notice any cooling issues. With low temp sensor, temp barely makes it above the first line on the gauge. My car has a small oil leak from previous owner, who I think forgot a seal near the balance shaft when he had timing belt changed, and it's much easier to catch the oil with them off. It's not a lot of oil, maybe a drop every couple of hours,but if I had those trays on, what a mess.

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[flash]

ah - missed that - thanks

yeah - i'm absolutely sure about the underbody pieces - plenty of people have noticed the difference - you really won't see it on your gauge unless you are in very hot weather, but you will see it in the recovery time

there is quite a bit of data out there on this - just do a google on "belly pans"

i have done quite a bit of work removing extraneous air from the engine bay by adding other items to block its entry, and the under hood temps show a measurable drop

the under body panels also help control front end lift

i understand about the mess and hassle though

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