924Board.org

[wombat]

its getting closer but today I took it for a drive around the backstreets in my area for a while and notices a few strange noises that were not picked up on the RWC inspection.

1. is coming from the belt area and sounds like a bearing or tensioner or something like that it is pretty minor now but may develop into something noisy if I dont get on to it soon, this one I think I can handle but anything anyone wants to add would be great too.

2 this is the one that worries me because I am guessing that it was not picked up because the mechanic doing the RWC couldnt take it for a drive as it was not registered. The noise is only there when the car is in a drive gear and when the accelerator (gas pedal) is applied, the harder it is applied the noiser it gets, I first thought that I had left a spanner or something in the engine but this does not seem to be the case. it is a very annoying rattle coming from the front on the UK passengers side or the US drivers side, I had a quick look but couldnt see or find anything then I thought that I would leave it untill tomorrow as it is approching midnight and I have to work tommorow, any ideas on where to start my search would be most appreciated.

Oh and the lights that were going down up down up down up finally gave up and just stayed up even though they turned off I will change the relay and see if that fixes it.
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1977 924 2.0 Auto

[Ozzie]

Rattles under acceleration is usually 'pinging'.
It means your car is too far advanced, too lean, or a too low octane fuel is being used.
I used PULP fuel, have it at 8deg BTDC and run it a little rich.
If it is an AU car you will not have a cat so check your exhaust pipe.
If it is white inside its too lean.
Black too rich.
Mine is dark grey, nearly black.
Otherwise it sounds like coke bottles hitting the road.

If the timing belt tensioner is too tight it will groan.

Headlight relay on the motor may have corrosion on the terminals.
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Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

[wombat]

I didnt think it was pinging because when I say acceleration I mean acceleration in gear, If you rev the motor when it is not in drive no noises but when in drive and acceleration is applied you get this bloody anoying rattling noise. I am a little stumped, if you still think pinging I will check it again but when only very light acceleration is applied or when you listen behind the rattle the engine sounds like it is running perfectly????. HELP????????
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1977 924 2.0 Auto

[Rich H]

Pining/pingnig will only happen when the engine is under load, revving stationary is very light load, as it accelerating gently.
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1994 Lotus Esprit S4 - Work in progress...
1980 Porsche 924 S2 DITC Turbo - Original spec
1978 Homo-Sapiens - Tired spec
1953 Landrover S1 - Pensioner Spec

[RC]

+1^ Dont think its pinging either.

Front noise is most likely timing belt tensioner. Cheapest in Oz is $50 from Bob Whyms Auto (Syd).

Rattling eh? Probably can dismiss the expensive rubber damper then as it is a clunk clunk on and off throttle. Time to get underneath. Check both engine mounts especially the drivers side with the spring. Revving in N wont do much but when in gear and accelerating the torque will twist the motor and driveline. So maybe the exhaust is knocking on something or is faulty. Had similar noise from a dud muffler that had cracked around the flange.

Roger

[Rich H]

Slightly OT:

Will torque twist the motor? I was under the impression you get twist on a motor as the torque reaction issorted out around the differntial, as this engine has a transaxle there is no left/right torque reaction the reaction is up/down on the motor around the rear axle. Or am I talking sh!t?
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1994 Lotus Esprit S4 - Work in progress...
1980 Porsche 924 S2 DITC Turbo - Original spec
1978 Homo-Sapiens - Tired spec
1953 Landrover S1 - Pensioner Spec

[RC]

No, wouldn`t say that because the torque tube and trans tie things down. Maybe should have used the term inertia or whatever. Isn`t it Newton`s third law- for each action is an equal and opposite reaction. I`m on physicist so stand to be corrected here.

Suffice to say, the engine does move on its rubber mounts so check if the exhaust or anything else id knocking.

Roger

[Ozzie]

Easy way to check if its pinging. Get the timing light out, set it to 5 deg when hot and take it for a spin.
If its gone or better, it was pinging.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance