924Board.org

fcapri · Joined: 23 May 2004 Posts: 5

hi

I bought a 924 (my first one ) and its having a little problem, when the engines runs, it makes a bad noise. something rattling from the bottom.

the engine didn't run when I bought the thing, because the salesman told me that the oil pump was broken.
could it be the pump? when the engine runs, the oil pressure is at 2bar, and there is oil on the cam shaft, so the pump is still working.
it appears that the sound is coming from the direction of the clutch.

and where could I find the oil pump?

ps: i'm still reading all the topics, and it is possible that I will find the answer later

Jazzerpet · Joined: 07 Apr 2003 Posts: 186 Location: Omaha, NE.

The oil pump is located at the front of the engine around the crank.
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1980 931
1985 ½ 944
Member of the “Omaha Crew”

Sleykin · Posted: Mon May 24, 2004 12:49 am Post subject:

What year?
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Glenn Neff
Medford, OR
87' 924S

924RACR · Posted: Mon May 24, 2004 12:56 am Post subject:

Doesn't sound like there's an oil pump issue offhand - should be 2 bar at idle except when hot it can dip as low as 0.5-1.0 bar, and around 4-5 bar at speed.

However, it is important to isolate if the noise is internal or external to the motor.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

Smoothie · Posted: Mon May 24, 2004 2:28 am Post subject:

Also post the transmission type (mainly whether it's auto or manual) and other conditions - sound changes while moving? in or out of gear? coasting out of gear? changes on left or right turn, stopping, accelerating, etc.
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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

fcapri · Joined: 23 May 2004 Posts: 5

Joes924Racer · Posted: Mon May 24, 2004 8:46 am Post subject:

sounds like bearings though if theres no metal shavings in the oil
thats not it.
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1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

welder · Joined: 16 May 2003 Posts: 158 Location: cumberland,maine

When you rev the motor, does the rattle increase with the rpm's, or is it just constant? Is it a sheet metal sound, or definately inside the motor?
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I have a 78 n\a currently under restoration.

fcapri · Joined: 23 May 2004 Posts: 5

78porsche924 · Posted: Tue May 25, 2004 2:40 am Post subject:

First things first, do the cheap and easy thing, check the exhuast heat shields under there. Also check the exhaust clamps if there are any. Might just be something as simple as that. It happened to my sisters car and her and my parents thought the tranny was shot. Exhaust clamp rusted and broke and rattled like crazy. Took 5 minutes to diagnose and fix.
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90 944 S2
78 924 NA <---now sold and killed by new owner
snailshell trans
Bae turbo kit
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gohim · Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA

Rattles....

Sometimes it is hard to aisolate exactly where they are coming from.

At the front, could be a cracked timing cover. On the 924, the timing cover is mounted with holes with rubber grommets, and metal sleeves that go inside. The rubber rots, and the timing cover vibrates until the metal around the hoels crack, and then they can make a buzzing sound.

The sheet metal heat shield on the top of the exhaust manifold that is supposed to help protect the spark plug wires has a tendency to crack and buzz/rattle also. The later model year cars have an improved part.

Also the exhaust manifolds themselves have a tendency to crack on the early cars. The cracks grow from the bottom, and in an advanced stage can grow up into the top, but will be concealed by the spark plug heat shield. Later model exhaust manifolds are reinforced on the bottom side with huge ribs. New replacement exhaust manifolds for early cars also have the big reinforcement ribs. You can crack for cracks on the bottom of the exhaust manifold with a mirror, from under the hood, without crawling under the car.

Early cars with a EGR filter and tube (mounted on the left side of the engine block). The EGR filter has a tendency to rot out on the bottom, so you need to check the side against the engine block with a mirror. The tube that runs to the exhaust also cracks from fatique, and will buzz.

80 and later cars can crack the downpipe at the lower end support, where the downpipe is joined to the cat adapter pipe. This can also buzz.

numbbers · Posted: Tue May 25, 2004 9:06 am Post subject:

Well guys, I have had a rattle for several years, and it is definitely in the exhaust. To be more specific, in the cat. I have had it off and you can hear the rattle when you shake it. I assume the substrate has crumbled and is ratling. Someday, I will cut a hole in it and dump out the crap, then weld it back up.
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1980 924 Turbo

fcapri · Joined: 23 May 2004 Posts: 5

I made a little movie of the engine when it rattles.
http://users.skynet.be/fa438830/porsche.avi

it has been compressed with divx 5.1.1

Smoothie · Posted: Thu May 27, 2004 1:01 am Post subject:

Nasty sound.
It's reminding me of the last time I had a connecting rod bearing failure on the Honda. No offense intended though.. a Porsche can sound a little like a honda when the Porsche's sick.
_________________
"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

Paul · Posted: Thu May 27, 2004 8:37 am Post subject:

Please drain the oil and check for metal, that sounds like a rod bearing to me. If it is, you will find a lot of metal in the oil.

DON'T START IT AGAIN!