rattle at 6K

[nostatic]

While blowing some carbon out of the car today, as I climbed to 6K I heard a rattle from the rear of the car. I backed off and it immediately went away. I didn't get up to 6K again on the drive, but nothing at 5K. It sounded like a sheet metal rattle (but I couldn't exactly get out and look at that point in time). Any ideas? I have the original tensioners if that makes a difference.

[Bill Douglas]

Todd, that's the famous SC Death Rattle! I would be concerned.

But in the real world I would have someone else drive the car while you crawl around in the back and try to identify the sound. Do it first underload, then if you are brave enough, try it while you are parked with the engine lid up. Maybe wiggle everything first before any tests

[makaio]

Dr static,

I don't think it would be tensioners if it stopped once you backed off.

My car made a similar sound when my first GHL muffler split at the seam. Right between 3000-3400 rpms. Bellow or above that, no rattle sound.

[Superman]

Relax.

[R22tech]

Heat shield for Cat. conv.? description sounds like an exhaust rattle, so check all muffler straps, clamps, bolts, ect.

[nostatic]

Originally posted by Superman
Relax.

That's what the Xanax is for. I'm not that worried since at 5500rpm is sings right along (and what a song). It sounded exhaust related, but I was just curious.

Thanks Bill, I think i just forgot to turn the light sabre off

[R22tech]

I'm not sure if yours is like mine, but check here:





sometimes LOOSENING the bolts that hold this shield on just a touch does the trick!

[911pcars]

Todd,
Do you think it might be detonation? Check ignition timing. Check for any loose sheet metal, then try it again. Try it with a load of 93 and/or race gas and see if it makes a difference. We don't want too many SCWDP cars falling by the wayside. :-)

Sherwood
http://members.rennlist.org/911pcars

[Early_S_Man]

Sounds like something exhaust or sheet metal related -- not tensioners!

Don't worry -- the tensioners will let you know, each and every time you start the engine up cold -- when their time has come ...

[nostatic]

I don't see that on mine...only a smaller shield:


nothing on this side


I do have one of these though:

and one of these:

[island911]

At 6k (and only around 6k) it's not likely detonation. The pistons start lossing their ability to pull a full charge of air around 4k.
My guess too, would be sheetmetal rattling.
. . or your SC is simpley saying; 'Todd, I need some SSI's

[nostatic]

"yeah honey, I gotta fix that noise. A set of SSIs and a Dansk should do it...less oxidation down there too."

Let's see...how much did she spend on Japanese wood block prints in the last month?

[surflvr911sc]

Dr. Static, I have found your problem!!

You have no signs of oil, grease, or sluge under your car. You should really know better, know wonder everything under there is rattling around. Nothing to keep it together!

[surflvr911sc]

Almost forgot, the pots & pans arived today. I'm waiting for her to get home to open them, and cook me dinner!

[nostatic]

Dr. Williams, I hope it is worthy of Iron Chef status. If not, tell her to get the money back and buy some AllClad (and save a $K or so)

[Botman]

NS,

Perhaps you have the dreaded SCWDP "sticker shake syndrome."

Did you have this mysterious rattle BEFORE pledging your allegiance to this subversive group by applying an obviously defective decal to your vehicle?

Are you sure you're not hitting the rev limiter?

[Superman]

Lots of possible sources. Lots of sheet metal back there. Also, the guts of catalytic converters sometimes come loose and if they do, they'll rattle.

[KFC911]

I detected a 'rattle' under hard acceleration a couple of weeks ago on our 'NC run'...it was very intermittent, and although I haven't fixed it yet (car's on jack stands for other reasons), I'm quite sure it's a loose muffler strap.