Engine rattle

[S3DaveP]

I have a 1990 S3 2.9 which has a distubing noise in the engine. When the revs get to 5500 it emits a metalic rattling noise that sounds like valve bounce but there is no loss of power it pulls to 6000 ok. There is a particulary noisey tappet on the left bank all other tappets seem to get quieter as the engine warms up but this one only is still a bit rattly when fully hot. please can anyone suggest a likley cause?
Also the water pump is leaking slightly what pump do i ask for or are all 2.9's the same as the sierra/granada engine, a part number would be very useful

Cheers

Dave P

[bondingi]

Try sorting out the valve gaps first then check the vacumn advance on the distributor as it may not be working properly and you are getting pre-ignition or pinking.

[peterc]

There is sometimes confusion over which pump is fitted. Best suggestion is to strip off the old one then take that to a good motor parts supplier and compare it to the new one they offer you.

[dern]

Are you sure it's the engine and not a loose baffle in the exhaust?

Regards,

Mark

[S3DaveP]

From my memory i didn't have this noise in the summer when the roof was off, i only remember hearing it when the roof was on. The exhaust has a slight blow when cold, but almost dissapears when hot so it could be an exhaust problem ( stainless steel system was fitted @ 4 years ago ).
The weather at present is too grim to investigate fully , but i intend to adjust the tappets soon and see what that does for it.

Thanks Dave P

[dern]

When my tappets are out they rattle all the way through the rev range. My s3 buzzes at about 4000rpm (I think) and having had someone run the engine up the that speed for me when I wandered around the car I found it wasn't the death rattle of my engine as I feared but just the exhaust box buzzing a bit.

Good luck,

Mark

[keithyboy]

Dave, I had a similar problem with my previous S1 which manifested itself shortly after fitting a S/S exhaust. It sounded like a resonating rattle at about 2400 rpm as I recall. I thought it was either a tappet or a loose weld somewhere in the exhaust system. I got the exhaust replaced on the strength of the latter suspicion which I assumed to be wrong as the problem persisted afterwards. I never did get to the bottom of it but always drove quickly from 2 thru 3,000 rpm! Even now I still think it was a rogue tappet - clearances were all OK though!