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Knocking sound from bell housing???
#1

As part of my engine rebuild I replaced the clutch, flywheel (RSB 18#er), pressure plate and throwout bearing. Finally got the engine right (discussed on another thread), BUT...
There is a very noticeable knocking sound coming from inside the bell housing. The noise varies directly with rpm. It does seem to come and go, but I can't quantify anything that might be making it come and go (like pressure on the clutch pedal). Any ideas?
I've only driven car 1/2 mile and not above 3,000 rpm yet. The noise is there with the car running and sitting on jack stands.
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#2

obviously a knocking sound is very bad, and you need to stop running it and find it

if it's in the bell housing, there are only a couple of things that can create it, all of which require pulling it back apart to find it and fix it - if i had to guess, i'd say it's related to the release bearing (like maybe the shims got put on the wrong side)

i would pull the plugs and spin the motor at starter speed to see if i could nail it down farther first though - if that doesn't tell you, then yank the bell housing side cover
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94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
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#3

With the clutch pedal depressed all the way the knocking goes away.

I've got the bell housing side cover off. I might recatagorize the noise as a rattle rather than a knock. Tough to tell. I can't see anything obvious inside the bell housing. I don't have anyone here to push on the clutch while I'm looking into the bell housing, so further trouble shooting will have to wait.
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#4

Here's a picture looking into the bell housing. Anything look wrong?
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#5

Looks correct to me. I am just wondering if it could be the bolt going into the half shaft that might be slghtly proud?

Have you turned the motor while you are down there? If not that would be my next step. Maybe have someone turn the engine by hand at the crank and then you can listen for the sound while down there?

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#6

Well...I started the engine again with the bellhousing cover off. Low and behold, no noise. So I drove it around the block with the cover off. No noise. Put the cover back on. No noise. Everything in there was new; maybe something had to "break in" a little. Can't imagine what it would be though. In any case, this is no longer an issue until further notice.
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#7

lol - whatever it was, it fell out?
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94 Midnight Metallic Blue Cab Porsche 968 w/deviating cashmere/black interior and WAY too many mods to list - thanks to eric for creating www.968forums.com



"It isn't nearly as expensive to do it right as it is to do it wrong."
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#8

"lol - whatever it was, it fell out? "

Yeah, I'd get under there again with the bell housing off and a good light, and make sure nothing vital is missing...
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