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-   -   Listen to my engine (http://forums.pelicanparts.com/porsche-911-technical-forum/355271-listen-my-engine.html)

Paul Ferradas 07-02-2007 09:24 PM

Listen to my engine
 
I have a couple of questions for you guys that have good ears for a Carrera engine. This is my first Carrera and I haven't compared the sounds my engine makes to others so I just want to know if it sounds right.

My first gripe is the fan noise that becomes very apparent around 1:12 into the video. This sound drives me nuts sometimes. It's the howling sound of what I think is the alternator fan. If os, is there anyway to quiet it down or is this normal? What creates this sound? Is it the air passing over the cooling fins? It's most apparent at about 2400RPMS

The second sound I thought it was the valves, it's a clacketing sound coming from the right side of the engine. It seems to quiet down once the engine has warmed up a bit. Very apparent when the engine is cold.

Here's the link to the video, listen carefully :)

http://www.ferradasphotography.com/pcar/carrera.wmv

tt_targa 07-02-2007 09:42 PM

Beautiful car. Love the color.

I would have to say that it doesn't sound like alternator/fan to me. I would have to say there is definitely something wrong.

Could be everything from a loose catalytic converter shield to valve train issues. Hope it's not the latter.

PatrickB 07-02-2007 09:53 PM

I can't get the video to play past about the 24 second mark.
The whiney noise I hear is most definitely from the alternator.
Bearings sound like they're going. Not too critcal though... Mine made about the same level of noise for several years before I finally replaced the alternator. Mine was starting to show more signs of failure. The headlights would flicker when at idle...

Paul Ferradas 07-02-2007 10:04 PM

I take it the best way to check for that is to disconnect the fan belt and run the engine for a few seconds and see if it goes away?

911mot 07-03-2007 12:06 AM

Quote:

Originally posted by Paul Ferradas
I take it the best way to check for that is to disconnect the fan belt and run the engine for a few seconds and see if it goes away?
Yes but only for a few seconds. DO NOT DRIVE IT WITHOUT THE BELT !!

Dutchie 07-03-2007 01:16 AM

one more for the alternator or could it be the aircopump ? is it easy to take off the aircopump belt ? If so i would try that first it,s without risk.
I,m not grazy about running the engine without a fan maybe when its cold ?

bump for the experts :)

NY65912 07-03-2007 02:30 AM

I find my 3.2 to be very "winey" due to the fan, (but I dig the sound).

I personally would not worry about the high pitch sound coming from the fan, all 3.2's that I have heard, especially with stock exhaust sound like that.

You do seem to have a valve clacking noise. I think a valve adjust is in order.

I would do further investigating just to put my mind at ease.


Good Luck

kqw 07-03-2007 07:30 AM

Quote:

Originally posted by Paul Ferradas
I take it the best way to check for that is to disconnect the fan belt and run the engine for a few seconds and see if it goes away?
I agree......

I suspect that you may have play in the crank shaft pully. or...alt bearings or your compressor.

When you remove the belts (both), start the engine for a few sec's and rev. I suspect that the noise will go away.

Put the fan belt (only)on and start the engine again and the noise will probably return.

remove the fan belt and connect the compressor belt only. I suspect that the noise will remain or if it goes away, it's your alt.

Simple checks:

Check the number of shims for the fan pully (a combination of 6)and....check the tension on the fan belt..i.e., belt is not to taught.

With belts removed, check to see if there is any play in the crank shaft pully.

rgdalacrity 07-03-2007 07:49 AM

Make sure to rule out a collapsed timing chain tensioner. It is rare, but it did happen to me at 130,000 miles.

Paul Ferradas 07-03-2007 08:01 AM

Thanks guys, I'll work on this stuff tomorrow and provide a follow up. :)

Paul Ferradas 07-03-2007 08:03 AM

How would I rule that out? Can a visual inspection of the chain tensioners be done with the engine in place?

rgdalacrity 07-03-2007 08:18 AM

It is not a difficult task to check the tensioners. There are a few posts that describe it. The unfortunate thing for me was that I ignored researching the post and panicked and took it to the shop. They did a good job, but charged me 4 hrs at $85.00 an hour and $250.00 for the tensioner. My car has the AC stripped out, so it would have been easier for me to do the work. The sound of a collapsed tensioner is a rattling / grinding sound from one of the sides of the engine. As of now, let's not jump to conclusions. Relax and first rule out the parts associated with the belts. How many miles are on your engine?

Paul Ferradas 07-03-2007 08:21 AM

My engine has 74K miles on it.

rgdalacrity 07-03-2007 08:30 AM

It would be very unusual for the tensioner to go at that mileage. If you can, do as the others suggested and take the belts off and run the engine for a short duration while filming. I would be interested to listen. In the mean time you may get some more experienced listeners to respond to your post.

rcaradimos 07-03-2007 04:14 PM

Just as the engine stops you can hear some sqeeking, sounds like dry alt. bushings. Remove belt like posted. Could be a bad water pump! LOL

barney911rs 07-03-2007 06:54 PM

Overall it sounds like all the 3.2 air cooled motors. Make sure the engine sound pad is in good shape. Very tough to do with the engine in the car, but it's just lose you may be able to re-glue part of it.

That clacking sound very well could be the valves. If you have a small diameter piece of hose or pipe, you might be able to isolate where the noise is coming from, sort of like a stethoscope.

Paul Ferradas 07-03-2007 07:12 PM

Thanks for the info. I have no sound pad :)

450knotOffice 07-03-2007 07:40 PM

I listened to your engine a few times and for the most part, it sounded normal, other than the low speed clacking sound. I'm not sure what that might be.

As for the whining noise, I think most of the guys are right. I think your alternator bearings might be wearing out. Not a big deal if that's the case.

The sound pad has no bearing on the sound. Don't worry about that. It only insulates sound from the cabin.

Good luck to you.

Paul Ferradas 07-03-2007 07:58 PM

So what's the step for replacing the alternator bearings? Or do I need to replace the entire alternator?

Paul Ferradas 07-03-2007 09:05 PM

So I took the alternator belt and the fan belt off and gave it another try. I think it sounds pretty much the same to me. Maybe just a tad quieter but again my ears are all that trained. Here's the short video for this:

http://www.ferradasphotography.com/pcar/carrera02.wmv


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