Scraping noise when moving from a stop

[maldotcom2]

Hey guys. VS Manual, last week my car has started to make a "tinny" grinding noise coming from somewhere under the front of the car when moving off from a stop.

It's good all through the revs in gear and in neutral, spark plugs look normal and compression is fine too. When letting the clutch out slowly in neutral there is no noise. Only under load in first, I cant hear it doing it during normal gear changing, but then again the car is fairly loud. Tried jacking up and spinning the front wheels by hand, no problems.

Front end bushes are all new, and the engine and clutch have done less than 10,000k's. Drive shaft has done less than 20,000k's.

[VR_Acclaim]

It could be an engine mount that's what my vs did..and it sounded like a wheel bearing

[maldotcom2]

Mounts were changed with the engine. I guess it's possible, i'll have a look.

[hako]

Haven't got a pebble stuck in one of the front calipers? Does it do it in reverse?

[maldotcom2]

Yeah it does it in reverse too. If it was front brake related it should have made the noise when i spun the wheels though.

[seq4x4]

What about that stone guard plate to protect the rotors, are they nice and secured and not loose?

[hako]

Can you feel any roughness coming back thru the clutch pedal when the noise happens? ..... does it do it if you start in 2nd gear or 3rd?.....was pilot bearing replaced in flywheel/clutch?....does noise still happen when clutch released (pedal up)?

[seq4x4]

By pilot do you mean spigot bearing?

[hako]

Yes - spigot/pilot bearing....the one that sits in the flywheel...if dry they can make a squeaking noise when dis-engaging clutch on take-off but not make a noise if in neutral and you dis-engage clutch - just a long shot.
See this link: http://www.ls1tech.com/forums/manual...going-out.html

[VrWagz1]

not just a fugged shocky or somthin is it, lift the car under the front gaurd by hand on both sides. and give the front end a good nudge up and down.

[maldotcom2]

Ok the noise is getting worse so i've isolated it to this: Happens only under very light throttle, reguardless of whether car is rolling or stationary, and reguardless of clutch position. Also regardless of gearstick, brake, or handbrake position.

Brake guards are tight, no roughness coming through clutch pedal, spigot was replaced with engine/clutch. Front shocks have done less than 1000k's. It's gotta be something rubbing on the engine or exhaust. If you can imagine a bolt jiggling around inside a header pipe - that's what it sounds like.

Keep trying with the suggestions, i tried to get a sound recording but it didn't work. I'll have a look again tommorrow arvo.

[hako]

Not the nose of the starter making contact with the ring gear when the crank moves forward (slightly)?....loose baffle in muffler?.....is it possible a sagged mount is allowing the block to lower/lean when supplying motive power and causing a header or anything connected to the motor rubbing or coming in contact with the chassis/body?....look for witness marks which are best detected at night in total darkness using a torch (don't ask me why but apparently they eye/brain focusses on a smaller area)
Also: try with A/C on/off, bonnet closed/popped, serpentine belt on/off.

We all know this will turn out to be something very simple!!!

[maldotcom2]

It's distinctly coming from under the car about in line with the driver's door. It's not possibly a valve train noise amplifying through the exhaust?

[Dayvo]

Had a look in the trusty Haynes repair manual and it says Problem Metalic grating sound consistent with vehicle speed. Cause Pronounced wear in the universal joint bearings . Renew U- joints or driveshaft as necesary . Might be worth a look

[hako]

Maybe a split/cracked exhaust manifold on drivers side which leaks once pedal is opened (more exhaust)....alternator bearing failing?...not the exhaust down pipe drivers side touching body?

[seq4x4]

Bought a VT one night and we couldnt figure out what this rattling noise was. Turns out the spring to return the key from cranking it back to on was broken. So it was stuck half engaging the starter motor. Could that be it?

[maldotcom2]

Thanks for the tips, i'll check it all out and get back, hopefully with a solution!

[slepar]

i had a very similar thing happening in my miss's vr, it was the cat converter the stuff inside (i think its called honeycomb or something?) anyway it was split and was causing an annoying noise, its only held on by 4 bolts so might be worth checking out

[maldotcom2]

Well i was about to try your idea, slepar. I crawled under the car and gave the cat a whack with my hand, sure enough it made the noise. There's a shield/heat dissipater on the cat that's spot welded on both sides, and one side had come loose and was vibrating.

Thanks guys.