Weird grinding noise between 2-2.5k rpm

Kikuchi · Postby **Kikuchi** » Thu Apr 12, 2012 5:58 pm

Since I got my car, there's always been a weird sort of grinding/rattling noise whenever the revs hit between 2000 to 2500 rpm. It doesn't happen when not in gear, so it leads me to think that it's gearbox related. Happens in all gears (haven't tried reverse yet as I don't reach 2k rpm when in reverse...)
Does anyone know what this could be and if it is serious or not?

lee · Postby **lee** » Thu Apr 12, 2012 6:07 pm

Does it happen when you leave the gearbox in neutral, clutch out, and revving the motor up?

Kikuchi · Postby **Kikuchi** » Thu Apr 12, 2012 6:47 pm

havne't tried it, i'll give it a go later, when i last checked i clutched in and then reved

Postby **NitroDann** » Thu Apr 12, 2012 10:19 pm

I bet its the heat shield.

Dann

JBT · Postby **JBT** » Thu Apr 12, 2012 10:20 pm

Which model MX-5 :?:

Kikuchi · Postby **Kikuchi** » Thu Apr 12, 2012 11:28 pm

sorry forgot to mention. nb8b '01

Kikuchi · Postby **Kikuchi** » Fri Apr 13, 2012 5:00 pm

Tried it out today, in neutral, clutch out, no grinding.
clutch in, no grinding

It only happens when in gear and it happens in all gears.

I'll have a look at heat shield to see if it's loose.

bruce · Postby **bruce** » Fri Apr 13, 2012 5:02 pm

I was gonna say heatshields (but they're more an NA thing).
Or......spark plug leads! (Whew, I feel better now).

Postby **NitroDann** » Fri Apr 13, 2012 5:12 pm

Its a cluster shaft bearing then.

Dann

Russellb · Postby **Russellb** » Fri Apr 13, 2012 7:56 pm

NitroDann wrote:Its a cluster shaft bearing then.

Dann

Hard to say .
If it makes noise in 4th (5 Speed) or 5th (6 Speed) the the LAY shaft bearing are not under load.
but if its the noise is in all gear but the ones above then YES LAY saft bearings.

Really need more INFO "IE", year, mods, Everything else.
This will help to point you in the right direction

mitch_f1 · Postby **mitch_f1** » Fri Apr 13, 2012 8:21 pm

Just gonna put this out there and say flywheel chatter?? Is the car stock?

Kikuchi · Postby **Kikuchi** » Fri Apr 13, 2012 8:30 pm

engine and transmission wise stock, and as said in previous post, it's an '01 nb8b. just under 90k on the speedo.
only mods that I think would affect this is heavier rims 16x8 but it was doing it even on stock rims before.
i won't be driving tonight, but i'll check again tomorrow whether it happens in 4th 5th and 6th but I'm pretty sure it does.

this happens without fail exactly at 2k up to just below 2.5k rpm.

Postby **NitroDann** » Fri Apr 13, 2012 8:34 pm

If it only happens at some rpms (frequencies) it MUST be vibration based. Unless im not thinking much.

Dann

Russellb · Postby **Russellb** » Fri Apr 13, 2012 8:51 pm

NitroDann wrote:. Unless im not thinking much.

Dann

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