[SILVY968]

Can anyone start me off in my search?



I hear what sounds like a sympathetic vibration when I have the engine at 3100-3200 rpm. The gear does not matter. When the tach runs by 3100 rpm I hear the ringing, metal noise. It only lasts a second or two.



It seems to be coming from below the glove box, but on the engine side of the firewall. I can not see or feel anything loose either inside or out. It is not in the glove box nor on the plate on the foot well covering the computer. Can anyone think of what it might be? It is high frequency like a piece of tin or a loose plate is vibration at that exact frequency. ABS?

Thanks

Brian

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[Cloud9...68]

Have you gotten under there and checked the exhaust heat shields? A screw holding one of them may have worked its way loose.

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[DaveN]

Both my cars had/have that same noise. It was the head shield. My S2 noise went away after I have the clutch done because reassembly tightened and shuffled that part a bit. My 968 does it to the point of embarassment at about 2100 just after I had and lightened RS flywheel and clutch put it. It's my spring project when the inurance goes back on and I reassemble the car <img src="/forum/images/smilies/968/rolleyes.gif" class="smilie" alt="" /> to get to a lift and fix that rattle.

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[SILVY968]

[quote name='Cloud9...68' post='63639' date='Nov 29 2008, 08:44 PM']Have you gotten under there and checked the exhaust heat shields? A screw holding one of them may have worked its way loose.[/quote]



Checked from the top only. thanks for the tip. I'll check when I do the oil change in a week or 2.

Brian



[quote name='DaveN' post='63651' date='Nov 30 2008, 01:21 PM']Both my cars had/have that same noise. It was the head shield. My S2 noise went away after I have the clutch done because reassembly tightened and shuffled that part a bit. My 968 does it to the point of embarassment at about 2100 just after I had and lightened RS flywheel and clutch put it. It's my spring project when the inurance goes back on and I reassemble the car <img src="/forum/images/smilies/968/rolleyes.gif" class="smilie" alt="" /> to get to a lift and fix that rattle.[/quote]

Dave, heat shield, right. I'll check it out.

Thanks

Brian

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[Duckman]

I also vote for the heat sheild as the offending part.

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[SILVY968]

[quote name='Duckman' post='63682' date='Dec 1 2008, 12:06 PM']I also vote for the heat sheild as the offending part.[/quote]

I'll either get that checked this wed when I get the timing belts checked (changed 2K Miles ago) or this weekend.

thanks

Brian

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[flash]

you could try poking around in there with a stick and see if you can make a change in the sound

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[SILVY968]

[quote name='flash' post='63709' date='Dec 2 2008, 07:21 AM']you could try poking around in there with a stick and see if you can make a change in the sound[/quote]

good idea for the weekend.

Thx

Brian

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[SILVY968]

You all were right. The heat shield over the passenger engine mount was touching on the heat shield directly above it.

we removed the passenger engine mount heat shield (2 bolts) and trimmed off about 1/8th inch of of the top and reinstalled.

No vibration noise any more.

The silence is wonderful!

Thanks to all...

Brian

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[rhudeboye]

Gotta love a low budget fix.



A bit odd that the noise only occurred at a particular rev.

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[flash]

it's a harmonics thing - it happens

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[Duckman]

Silence is golden. Gotta luv it.

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[Ryan]

Gotta ask why the shields were touching? Could it be your motor mount going soft and lowering onto the other shield?

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[flash]

may not have actually been touching - may just have been a case of the mass, or the angle of the bend - all i had to do to mine was put a kink in it to interrupt the wave

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[Ryan]

Nothing like a "kink" to interrupt your wave!!!

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[flash]

roflmao - i wondered who would go there first

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[SILVY968]

[quote name='flash' post='63790' date='Dec 4 2008, 08:27 AM']may not have actually been touching - may just have been a case of the mass, or the angle of the bend - all i had to do to mine was put a kink in it to interrupt the wave[/quote]



They were about 1/8th - 1/16th apart at rest, but at the exact frequency where one of them vibrated, it moved forward and touched the upper shield during the vibration.

Brian

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