Noise Coming from the car - Its driving me nuts!!!

[Hammer]

I need advice from my fellow forumites.

SYMPTHOMS:
I have an intermittent noise problem coming from my NB8B (SP). Noise seems to originate somewhere underneath the car from behind the seats backwards. Though it could be deceiving.

The noise sounds like metal hitting metal. Like if you tap a metal pipe with a metal wrench (ie. “tink”). The sound only happens in an instant and once at a time, and only with forward momentum – either starting from stop position (ie. traffic lights), or in mid-acceleration (ie. momentum fractionally interrupted due to the gear change). It does not seem to matter if it’s gentle (slow) or hard (fast) acceleration.

But where it seems to happen most frequently is when I reverse the car out of my garage – I reverse the car while slowly turning the wheel to the left, stop, select 1st gear then turn wheel to the right, while driving slowly forward. Most often than not, it will happen here. Being an intermittent problem also makes it difficult to track down.

BACKGROUND:
First time I heard it was immediately after I had my engine rebuilt (fitted a new clutch at the same time) in Dec 2008. On the drive home from picking it up, I heard it once or twice. But as time goes on, it seems to happen more frequently. I’ve only done 8,000 kms since the rebuild 15 months ago.

GEAR:
I’ve listed below what is different in my car – in case any of these contribute to the noise.

2002 NB8B SP

- Rebuilt engine

o Carrillo forged rods
o Arias forged turbo pistons & rings
- Turbosmart Boost Tee
- Turbosmart Plumb Back Kompact BOV
- Exedy Sports Tuff Clutch
- Racing Beat Style 2 Bar
- 17” aftermarket Alloys
- Mazda Leather seats - camel - from the Titanium LE
- SE front and rear bumper lip spoilers

So apart from the above it’s pretty much stock

ELIMINATED POSSIBLE CAUSES:
1. Loose items in the boot – totally emptied the boot and went for a drive - noise still happened.
2. Loose Disc Brakes – does not sound like the NB8B clanking loose disc brakes issue

SOME POSSIBLE CAUSES??:
1. Could it be the troublesome SP stainless steel exhaust? Though mine was replace twice (complete set) under warranty. The last replacement came with the improved design. So not sure if this is it.
2. Something loose (ie. nut or bolt somewhere in the body cavity behind the driver seat area?
3. Something loose in the suspension?
4. Something in the drive-shaft?
5. Something loose within the RB Style 2 bar?

Any suggestions will be appreciated. I just need to find this thing as its driving me nuts.

[taminga16]

Hammer,
Check all of the bolts asocciated with the drive line, particulaly cross member fasteners, forward momentum shifts the cross merber back on the bolts and when you reverse "TINK".

Greg.

[JBT]

Loose PPF bolts? PPF would have been loosed/removed for engine/gearbox removal.

[Villa]

Is it more frequent when travelling on a bumpy road?

I occasionally get a similar sound in my NB8B when reversing also but find that I can pick it up (if I listen really hard) on a bumpy surface from time to time. Mine is stock standard though and not an SP.

[Garry]

I had a similar problem. As JBT said, check your PPF bolts, especially at the diff end, or in my case the PPF was cracked around one of the bolt holes.

[Hammer]

Thanks guys.

I didn't know anything about the PPF bolts. I'll go and check them out when I get a chance to hoist the car.

Is it more frequent when travelling on a bumpy road?...

Villa, the road condition does not make a difference, its all with the momentum of the car (ie. shifting weight etc).

[greenMachine]

Prop shaft bolts. At the diff.



PS I'd whack all the PPF and brace bolts anyway - preferably with a rattle gun - just on principle!

[bruce]

OT-why did you get the motor rebuilt?

[Hammer]

OT-why did you get the motor rebuilt?

Typical SP issue of bend OEM conrods.