nlpy8b

Hey,

I recently installed a set of Pacesetter headers and Monster II kit with light weight flywheel. After a smooth install I am experiencing a rattling sound when under load (light load due clutch break-in). I can only describe it as a loose heat sheild type of rattle (like a thin piece of metal that isn't tightened down.)

The car drives absolutely stock other than this rattle so I was sure at first that it must be a loose bolt on the header. I have since gone through every bolt and fitting on the header install and haven't found anything. I'm worried now that it may be something with the clutch install.

I can't get it to rattle while in neutral lifted so I can isolate the location.I don't know what else to do but start going through every nut/bolt and trying to find it? Any suggestions? As far as I can tell so far no exterior bolt/componet is loose or hitting on anything else.

greddy91

iTrader: (2)

You say light load - does this occur with the clutch fully depressed or only when you're slipping the clutch and at low speeds 1-5 mph?

If so -and my bet is that you are - it's clutch chatter. Drive it until your break in is over and then go beat the **** out of it. It gets better...

(Hint: Don't break your rear diff in the process.)

LegacyGTBiggie

i had and have similar issues with my LGT. Went to a ACT street light single mass unit after having a ~26lb stock dual mass flywheel. And especially when cold and light loads(starting from a stop) I get a little chatter. After driving for a little it goes away completely in my instance.

whisler151

If its a loose rattle sound i'd double check the exhaust connections. My magnaflow has come loose in the past. I finally had it all welded up and lost some random vibrations.

nlpy8b

No...clutch fully released when accelerating through the gear. Not during engagement/disengagement. By under load I was refering to lightly getting into the gas (accelerating).

nlpy8b

That was my first thought since it has that heatsheild/loose band clamp sound, but I have gone through the entire exhaust system bolts now from the header bolts to the tips and didn't find anything. The only way that it could be the exhaust still is if it is the clearance above the exhaust because everything was shifted back approx 1/2" due to the LT header install. This may have lead to a clearance issue somewhere but I haven't found it as the rear connections of the exhaust are soft mounts.

nlpy8b

I took the car for a drive last night with the shifter boot/foam out and the rattle diffenately sounds like its coming from just below and forward of the shifter. Unfortunately I may have to drop the catback and driveshaft so I can lower the trans and see whats going on up in the tunnel.

GulfM3

iTrader: (14)

Sounds like your throw out bearing to me, did you replace it with the rest of the clutch install?
With the clutch in (pedal on the floor) you are putting pressure on the bearing and forcing it to be tight agains the pressure plate fingers, which quiets the bearing down. Then with the clutch fully out the bearing is loose from the clutch pressure plate and the minimal amount of slop in the bearing is causing a rattle sound.

blk04V

iTrader: (1)

Did you ever get this figured out? Mine is makin the same noise now but I haven't climbed underneath yet to check it out.

nlpy8b

No. I relieved some tight areas around the catback after the header install, put a thick coat of exhaust gasket sealer I received from the local exhaust shop on the band clamps associated with the connection pipes....still no resolve. Although the car drive perfectly I'm still getting a rattling sound on acceleration. blk04v stay in touch so we can get this figured out. I'm starting to think GulfM3 may be right and it may be clutch related even though it drives great.

I'm headed on the long drive to DFW to SNL's shop for a cam at the end of January so I may just put this off and let them look at it.

nlpy8b

You may be right here. I was sure (or maybe just hoping) that it was a header install issue. Would putting off dealing with a loose throwout bearing do any additional harm if I continued to drive it occasionally? Or would this just cause an annoying noise?

whisler151

SNL does all the work on my V, they are a great group of guys. Tell them about the noise and they will take it for a drive to hear the noise and diagnose it.

nlpy8b

After doing some reading and talking to a cobra buddy with a bad TOB..I'm still confused haha. It does only seem to make the rattling "marbles in a can" vibration when the clutch is out (engaged?) and accelerating but it doesnt seem to do it in neutral with the clutch out. This is the opposite of most people with bad TOB because they with get a vibration in the peddle and the sound when in neutral at idle but not under acceleration. Im my buddy's cobra the sound will go away with very light pressure on the pedal which makes sense as the load probably applies pressure to the bearing and prevents any vibration.

I think I'll go do some light acceleration with just a bit of pressure on the clutch pedal (essential slipping the clutch a bit) and see if the noise goes away. I would think this would be a fairly good way of diagnosing the TOB as the problem, correct?

nlpy8b

Well, I took it out for a drive and tried to apply slight pressure to the clutch during acceleration to see if the noise would cease. This did not work so maybe it isn't the TOB. I also don't think it is the pilot bearing because it doesnt make the rattling noise all the time- just with the clutch fully engaged (foot off the clutch) and accelerating through the gears. It seems to be primarily in the 2.5-3.5k rpm range.

I think I'm going to just try to baby it until I'm down to Dallas for SNL shop to look at it when I'm there for the cam job.

blk04V

iTrader: (1)

It looks like the only thing we have in common is the Monster II & lwfw. The noise seems to coming from right around the resonators for my Corsa. My dad took a look as well and seems to think it's coming from the cats which can't be the case for you.

His first guess was flywheel bolts loosening up but I would think that once a bolt is loose, it's loose and wouldn't only make noise when blipping the throttle.

Most recently, I can now get the noise if I rev the car while not moving, while when it first started I could only do it under load.

nlpy8b

Interesting, I was sure that mine was related to the header install but I can't seem to find anything related the the headers or catback that are hitting/vibrating against anything...I've checked every exhaust bolt, support, hanger ect.

I just hope I'm not doing any damage to anything by waiting until I get down to SNL for them to take a look. If I remove the shifter **** and boot the sound is appears to be originating from just forward to and below the shifter in the area of the bell housing or where the cats used to be. I have found no clearance issues though.

blk04V

iTrader: (1)

Frick... that does not sound good. I'm hoping for both our sakes that this is an easy fix.

blk04V

iTrader: (1)

I did another search here and at the other forum and couldn't find anything but I could have sworn someone else had this happen as well. From what I remember, all the bolts were tightened except one of the studs had broken off of the primaries where the headers (or manifolds) attach to the cat-back.

Now, I still haven't gotten under there and looked yet as I'm in Wisconsin and have a small garage but it'll be going on a hoist tomorrow. I'm just anxious as the idea of pulling the trans is NOT appealing AT ALL.

Twitch1

Didn't people have problems with Corsa rattling? Not really sure, but I thought I read that a couple years ago.

SNLPerformance

iTrader: (15)

nlpy8b, we just had a vette with a similar complaint from the sound of it and it turned out even though the exhaust band clamp was tight the actual exhaust pipe still had some play and was causing the rattle at a certain rpm range because of harmonics. We will definitely take a look at your car when it comes in and get to the bottom of it, if you haven't gotten a chance to figure it out before then. Thanks, Chris