ferraristyle

OK, so I just had my timing belt, rollers, water pump, and altenator replaced by a reputable Porsche shop that knows 928's. All the parts came from 928 International. Has maybe 200 miles since the belt has been replaced, which all came from the drive home from the shop.

So today I installed my new cat back exhaust also compliments of 928 international and I noticed a sound coming from the engine compartment. After much ear to enigne checking I discovered the sound to be coming from the timing belt cover area. The car also seems to be slightly missing at low rpms, WOT good to go and ablove 2700 or so good to go. The sound is intermintant and happens every 5 seconds or so.

So the question is what do you think is causing this sound. I'm supposed to go on a 500 mile ralley tomorrow and wonder if it's OK to drive the car. I have no warning lights at all and the car seems to run perfect over 2700 rpm's.

Insight? Comments?

1981 928, 5 speed.

Mrmerlin

park the car till the noise is found.
you might try removing one of the accessory belt at a time to see if the noise goes away, if none of the belts removed makes the noise go away then you should remove the right timing belt cam cover and look inside take a picture and post it if you can

s928s

+1000 with merlin....

I did my timing belt, all was ok. Was driving it around the block and herd a constant werring noise from the front engine area 1 mile from home. Pulled over and confirmed noise from the timing belt area. Did not drive the car back, called a tow truck as I just rebuilt the motor and was not taking cances.
Pulled the timing covers and found an extra 10mm washer had fallen between the cover and damaged 1/2 of the cogs on the belt for the whole length of the belt.

If I kept driving it I would be rebuilding the motor all over again.

The car also seems to be slightly missing at low rpms, WOT good to go and ablove 2700 or so good to go.

Sounds like the belt is off a tooth. Not too hard to check if it is the 81 in your sig. pull the upper covers, line up TDC on the crank and check the cam markers. Right side cam is probable off by a tooth. as merlin states, remove each accessory belt to confirm a possible component issue.

There will be other rallys or this one could be expensive if something fails. Call the shop and discuss your concern and have the car towed back.

NoVector

My "rattle" (~ever 15-30 seconds) was my WP bearing. With your motor hesitation, I wonder if yours is seizing(?) But I think that would be unlikely that soon on a new water pump. You might want to look down the breather holes of your timiing belt cover with a flashlight while the engine is running to see if the belt is tracking okay. Mine would drift when the rattle occured. It also had very fine glitter all over the smooth side of the belt... Hopefully, it's something simple like a loose belly pan or your exhaust is hitting something.

Tails

Listen to Mrmerlin. Even Porsche technicians can make mistakes, we are all human.

Tails 1990 928S4 Auto

ferraristyle

Any good shops anyone can reccomend in North Jersey, Fort Lee area? The people that did the work are in Philly, 200 miles away from me.

Mrmerlin

get your own tool box ,
and inspect the car yourself.
were here to help you do that .
you will appreciate the car even more once you solve this problem

blown 87

So can the folks that make water pumps.

s928s

I am just north of Philly and would be willing to look at it with you. I would investigate the noise/issue first prior taking a drive.

ferraristyle

s928, if you are around NYC anytime soon I'd be glad to get your opinion. I'm like 1.5 hours from where you are, so I don't know if your travels bring you to north Jersey.

Also, I talked to my shop today and they are going to explore options with getting the car back to them. In the mean time, since the car is down, going to do some preventative maintance replacing the front fuel lines.

j.kenzie@sbcglobal.net

I once had a similar sound that turned out to be the rear edge of the belly pan rubbing on the alternator pulley. I wish that luck for you.
Good luck,
Dave

ferraristyle

Car is going to a shop soon, I hope its something as simple as the belly pan. I was all over the car last night and couldn't find anything. Replacing my fuel lines while the car is down, and may do some other installs.

My problem is if it's a part, my shop says that I will have to pay for the fix all over again, if it's the istall they will pay for it. Any suggestions????

mx22

I'm NYC (Brooklyn actually). Not sure if I can help you much - got my 928 not too long either and don't know much about the car. That said, I'd be willing to meet up and try to help you as much as I can.

Cheers!

Big Dave

I had a similar sound. It turns out I hadn't fully tightened the ignition rotor. Hope it's something easy for you, too.

ferraristyle

Big Dave, where is the located, I will check that out tonight.