shmark

I just listened to the video and FWIW it sounds almost exactly like my failed water pump did. My 0.02c.

Jerry Feather

Hi Colin:

I am curious to know why you think that the cams do not turn at half the crank speed? You might count the teeth on the crank pully and the cam pullies and see if you don't find that the cam pullies have twice the number that the crank pully has. In addition, since the engine is a four cycle engine, the valves need to open and close only every other crank rotation, so there needs to be some way to keep them from doing that every rotation which is what they woud do if the cams rotated at the same speed as the crank; otherwise there could be no compression--just suck and blow, suck and blow, no compress and bang. On the other hand, perhaps you have in mind that the cams turn only one fourth the speed of the crank. In that case each cam would need to have two humps at each lobe. What is it you have in mind? Just curious.

Thanks.

Jerry Feather, FBA Certified
S4's (6)
KGJT

khalloudy

Ok... the car sounds the same cold or warm and as i rev the engine up, the clicking follows the engine RPM. I have uploaded another video as i rev the engine hitting 2000 rpm at the end.

http://www.youtube.com/watch?v=QUwRNgahjBE

P.S. when i mentioned the sound coming highest on the right side of the engine, i was using the perspective from the driver seat. Looking at the engine from the front of the car it is to my left (as in the videos).. that is why i am really praying its the air pump...

khalloudy

bump

Nicole

Khaled: When Bill and I chase noises on my car, we use a hose - like a piece of garden or vacuum cleaner hose. We hold one end to the ear, and move the other end around the area where we suspect the source of the noise.

The hose mainly picks-up the noises at its end. Once we get to the source of the noise, it comes very loud through the hose.

It is amazing how closely we are able to identify the source of such noises - try it!

Hope you can figure it out and get it fixed soon!

Glenn Evans

My laptop speakers aren't that good, but it sounds like a slack timing belt slapping against the timing cover to me. Remove the timing cover and, if you don't have access to a tension tool, twist the belt in your fingers. You should be able to twist it about 90 degrees and no more. If you can twist it more, adjust the tensioner until you can only twist the belt 90 degrees, then take the car to your 928 workshop to get the tension adjusted properly.

You risk the belt jumping teeth if it's too loose.

khalloudy

Hello all,

good news. Went to the dealership first thing this morning and they immediately put the car on the lift. Using the stethoscope, they pointed out that the Air Pump is kaput. removed the belt off it and the car sounds like a new car. Love the sound.

Bad news... Air Pump in Lebanon is USD $1,069 before VAT!!!! I will have to get one from the US as usual!!!!

Will drive the car for another year and next year i will retune the car with new TB/WP/plugs/etc/etc... The dealership does not have the 9201 or Kempf tool so we will have to get one at the same time to adjust tension... aghhhhh

Anyways, happy news!

P.S. thank you everyone for helping me with tracing the sound and assisting with the follow up.

John Speake

You don't really need an airpump.....

Nicole

Glad you found the source of the problem! Remember that trick with the hose next time!

Do they require smog tests in Lebanon?

khalloudy

John/Nicole,

nops we do not have a smog test, and my car is registered under Saudi plates right now (cannot be lebanese plated as it is not old enough or new enough - less than 8 years or 30 years+). Question is... would the lack of an airpump affect the catalytic converter behavior or life? would it cause me any issues?

Mrmerlin

just remove the belt and drive the car , you should not experience any adverse effects, unless you install an X pipe where you will get an additional 25 to 30 HP

Garth S

Kal,
Glad it was the air pump .... it had that characteristic sound - also agree with stan re leaving the belt off - no harm will come of it.

It is a fairly easy trick to remove the pump and support bracket. That has a benefit of improving access to the tensioner adjuster - just be sure to plug off the vacuum line, and the ~25mm air line that discharges from the pump.

I have a spare air pump if you choose to replace it.

Imo000

Aren't the bearings repalcable on the air pump? Might get lucky and they are standard bearings. If they are, you can get them pretty much anywhere.

khalloudy

I think for now we will stay airpumpless less weight, less drag and a couple more horses for me to flog around the streets

P.S. Garth, thanks for the offer, very generous of you. Maybe once i decide to put the pump back on, we will revisit this

jcorenman

Khaled,

Great news!! And I am very glad that I was wrong! (So much for science...)