Chatter Noise

[ruta87]

Hi All,

I am getting an odd noise from what sounds like somewhere in the engine bay. Around 3100rpm i get a noise which i can only describe as a metallic chatter. The best description would be to put a couple of bolts in a large metal bowl and move it round thats the closest i can think of! the odd thing is it stops fairly abruptly at around 3600rpm and seems to do it more with the throttle on. It doesnt sound like its coming from the engine, its sounds to clear to be that, but cant think of what else it could be!

The car drives absolutely fine. Ive had it checked but still couldnt work out what it was, i was wondering if anyone on here has had anything similar?

I was also thinking what the resonant frequency/RPM of the engine is??

any help would be appreciated!!

[SteveTusc]

Engine mount would be my guess if the engine got the all clear. They fail on the n/s by the exhaust and can cause the chassis plate to resonate at certain rpm.

[Robertjp]

Have you just started driving with your roof off after winter?

The reason i ask is that i always notice the distinct sewing machine noise from the engine more when the roof is off, its quite pronounced with the roof off?

Its most pronounced around 3000 rpm when exhaust noise is not loud enough to drown it out

[Robertjp]

Robertjp said:

Have you just started driving with your roof off after winter?

The reason i ask is that i always notice the distinct sewing machine noise from the engine more when the roof is off, its quite pronounced with the roof off?

Its most pronounced around 3000 rpm when exhaust noise is not loud enough to drown it out

One more thing - is the idle quiet or is there a pronounced noise at idle too? if its a ticking noise - get the tappets checked!!

[ruta87]

Dropped it off at RG, pointed out tHe noise, nothing came to mind so they are going to have a look whilst the check it over for Le mans! Will let you know the result if they find anything!

[Paulgooner]

Robertjp said:

Have you just started driving with your roof off after winter?

The reason i ask is that i always notice the distinct sewing machine noise from the engine more when the roof is off, its quite pronounced with the roof off?

Its most pronounced around 3000 rpm when exhaust noise is not loud enough to drown it out

Hi, can you explain more about this sewing machine noise. I have a noise, which now you have mentioned can best be described as a sewing machine type noise. When running at idle, its very quiet.

[nrick]

These engines are very noisy but the problem we all have is getting a good benchmark. I have had mine about 18 months now and at first I was constantly worried about the noise it makes, I have stripped the head, checked everything and cleaned everything. The cam chains had caught the cam cover at some time, the valve clearances were out. Having done all this work it still isn't any quieter. I don't really worry about it now to be honest.

[Robertjp]

What im talking about is nothing unusual, but it did worry me the first time i noticed it, but it a case of sp6 paranoia. I have had a full rebuild and when i noticed it (about 18 months ago) it had recently been serviced, but was the first time i had really driven her with the roof off.

These engines are loud, and the sewing machine noise, so long as its not interspersed with a loud ticking or clicking....is absolutely normal!!

[Paulgooner]

I don't think I am too worried, just a bit paranoid. Every noise I hear I start twitching. Before I bought the car it had just had a full service and tappets checked, by the same garage who inspected it for me. Still getting used to it I guess.
Thanks

[blueg33]

Could be aircon compressor.

I reckon its just normal.

[nrick]

Mine hasn't got aircon and still sounds like a sewing machine! I actually took the alternator off and had that tested as well but it was fine!

Halftime bearing set up, chains, followers all make lots of noise and there is a lot of resonance as well. It is just one of those things....

[blueg33]

Mine sounded like a sewing machine too, but had. Particular ticking rattly clatter that was the aircon according to Dom

[ruta87]

Mine doesn't have the air con, i can always hear the sewing machine noise but this is a different rattle/chatter. Always appears on the way up at 3700rpm until about 3900rpm and the same again on the way back down from 3900 down to 3700. It sounds normal though the rest of the rev range.

[m3jappa]

I'd be getting it looked at, I don't want to worry you too much but mine was similar description and it was the ottom end needed a new block.


Get it looked at just incase it is and you don't cause more damage.

[ruta87]

Nah, its deffo not the bottem end the sound is far to high pitched and rattley, bottem end would be more of a knocking sound. racing green have it now, im sure they will work out what it is and sort it!

Edited by ruta87 on Tuesday 29th May 07:22

Edited by ruta87 on Tuesday 29th May 10:06

[dvs_dave]

Could be the front brake pads rattling and resonating at certain frequencies. See if putting the brakes on stops the noise.

Also, check the heat shield plates welded onto the cat cans. The welds fatigue and crack over time causing the shield to rattle and resonate annoyingly at the engine speeds you mention. Mine was doing this for ages with no ill effects until one day the car fixed itself by shedding the said heat shield of its own accord, and taking the annoying rattle with it.

Mine's been decatted the quick and dirty way so the heat shields were superfluous anyway.

[Basil Brush]

Could be the timing chain hitting the cam cover. It's not unusual when it gets a bit loose.

[M50GRF]

I had the same sort of noise at the same rpm, after trying several things inc tappet set up I took off the aircon belt and the noise has gone.
Still got the misfire tho