View Full Version : Any advice on quieting sewing machine noise?


ccdominic
05-29-2012, 11:30 AM
just bought the rx7 and attempting to familiarize myself with the domestic motors as much as possible, so these build sheets are in another language to me. the sewing machine noise is driving me crazy and i could use a little direction on how to quiet it down. thanks guys!

mods are:

Stock Crank
Scat Forged Rods
Probe Forged Flat Top Pistons
Coated Bearings
Ported & Polished 241 Heads by SLP
PRC Gold Spring Kit W/ Titanium Retainers, Seats & Seals
TSP Chromemoly 7.40 Pushrods
TSP Custom Grind Camshaft 232/234, 595 / 598 , 114 LSA
LS6 Intake
Stock Throttle body and MAF
MSD Plug Wires
Stainless Fuel lines from engine to connectors under car
Z06 Return Fuel Rail W/Vac FPR


build info:
http://i219.photobucket.com/albums/cc70/KevinsTT/Picture2163.jpg
http://i219.photobucket.com/albums/cc70/KevinsTT/Picture2164.jpg
http://i219.photobucket.com/albums/cc70/KevinsTT/Picture2165.jpg
http://i219.photobucket.com/albums/cc70/KevinsTT/Picture2166.jpg
http://i219.photobucket.com/albums/cc70/KevinsTT/Picture2168.jpg
http://i219.photobucket.com/albums/cc70/KevinsTT/Picture2170.jpg

99Bluz28
05-29-2012, 04:06 PM
First find out what lifters it has in it, then buy/barrow a push-rod length checker to find out what you lifter preload is so you know if you're within the recommended range. I'd also check your LS6 intake to see if it has the two foam stips on the bottom.

M1tch
05-29-2012, 04:19 PM
My engine bay was louder noticably and i ended up having two loose spark plugs haha check that. But theres alot going on under there thats alot of valve lift so its going to be somewhat noisy man. Get a stethoscope and see if its your idler pulley/ ac pulley or just your rockers

thunderstruck507
05-29-2012, 04:32 PM
As mentioned above:

check for correct pushrod length to preload lifters, there are several part numbers which all require different preload

make sure the foam strips are still attached to the intake bottom

check rockers for damage or signs of excess wear



Depending on the cam lobes used, it might not get much quieter. Another thing is experimenting with oils. My engine was noticeably quieter with Castrol Syntec 0w-30 than Pennzoil Platinum or Mobile 1 5w-30.

ccdominic
05-29-2012, 04:39 PM
thanks guys! i'll be sure to try all of the above.

ccdominic
07-02-2012, 06:38 PM
ok guys. car hasn't been getting much attention. been so crazy busy at work. gonna start gettin her together. just bought a new gauge panel and speakers, but i also need to get crackin on this noise.

if it's nothing that will damage the engine i can live with it, but here's two vid's that display the noise (sorta). the dash and door panels out to get ready for the parts mention. any help would be greatly appreciated guys! thanks again.

if need be i can take our condenser mic and really get a good recording.

startup on warm day
http://youtu.be/m36vGhAOtH0

after a brisk little drive
http://youtu.be/W9uoPwcGIm8

99Bluz28
07-02-2012, 06:48 PM
Sorry, the sound is really distorted. You'll need to make a better sound clip for it to be of any help.

ccdominic
07-02-2012, 06:55 PM
yea i figured. i'll take the laptop and condenser mic out there tonight. get a good recording.

TyCZ28
07-02-2012, 08:53 PM
TWS car Squeaky just had the Comp Cams Trunion upgrade done and the "sewing machine noise thats typical from an LSx motor went away.. His valve-train is much quieter.. However the Procharger is as "squeaky" as ever =]

ccdominic
07-02-2012, 09:00 PM
http://youtu.be/0OJCNvqnqsg

this should be much easier to hear

ccdominic
07-03-2012, 02:26 PM
any takers?

Lee12609
07-03-2012, 04:00 PM
listening to the last video sounds like belt drive noise.

pull the belt and see if it quits. unless its just the video that makes it sound like that.

justin hover
07-04-2012, 07:59 AM
As far as my understanding goes...That sewing machine noise doesn't go away..I have it after my lts/duals went in...It's tollerable..but once my cam goes in I'm sure it will be noticably louder...I've read alot threads on this noise....Seems typical with no "for sure cure"...Unless it's a tapping or leak...It's just their to stay

A.R. Shale Targa
07-04-2012, 11:38 AM
That particular cam has pretty aggressive lobe ramps which elevates the
common LS1 valvtrain noise. Having quality lifters and proper pushrod pre-load
along with the trunion upgrade on the rockers helps to minimize the insanity.
Also the springs need to be properly shimmed. If the duals can handle .675
lift but your cam is around .600 sometimes they can experience surge unless
they are shimmed(shorter installed height) to within .060" of coil bind.
As some have stated...the engine oil viscosity can change this sound. I went
from Mobil 1 5w30 to Mobil 1 0w40 which is a European blend and apparently
has higher zinc content(similar to high mileage oil). This slightly reduced the
noise; not by alot but noticeable.

MIKEY'S 2002 TA
07-04-2012, 12:30 PM
that really doesn't sound bad at all. like noted above, it sounds like belt noise. the idler pulleys go bad on these cars. do what Lee12609 said and pull the belt and start it and see if it goes away. it seems tome that the top idler pulley goes bad more often than the bottom. i replaced mine with a manual style.

garygnu
07-04-2012, 05:25 PM
how many miles on your engine ?like mentioned above remove and check your rockers for missing bearings.remove all of your push rods and measure them.maybe get some harden push rods that are .025 longer then the 1 that currently in your engine.

ccdominic
07-05-2012, 12:44 PM
awesome info guys. i'll be sure to check out all of the above, starting with pulling off the pulleys. definitely appreciate the help.

ccdominic
07-05-2012, 12:50 PM
to be honest tho, it the sound is definitely coming from the valve train. the sewing machine aspect is much more audible inside the car.

ccdominic
07-05-2012, 12:52 PM
TWS car Squeaky just had the Comp Cams Trunion upgrade done and the "sewing machine noise thats typical from an LSx motor went away.. His valve-train is much quieter.. However the Procharger is as "squeaky" as ever =]

more info?

ccdominic
07-05-2012, 12:52 PM
how many miles on your engine ?like mentioned above remove and check your rockers for missing bearings.remove all of your push rods and measure them.maybe get some harden push rods that are .025 longer then the 1 that currently in your engine.

about 88000 on the car. engine was rebuilt about 5k miles ago.

ccdominic
07-05-2012, 12:55 PM
That particular cam has pretty aggressive lobe ramps which elevates the
common LS1 valvtrain noise. Having quality lifters and proper pushrod pre-load
along with the trunion upgrade on the rockers helps to minimize the insanity.
Also the springs need to be properly shimmed. If the duals can handle .675
lift but your cam is around .600 sometimes they can experience surge unless
they are shimmed(shorter installed height) to within .060" of coil bind.
As some have stated...the engine oil viscosity can change this sound. I went
from Mobil 1 5w30 to Mobil 1 0w40 which is a European blend and apparently
has higher zinc content(similar to high mileage oil). This slightly reduced the
noise; not by alot but noticeable.

this sounds like some solid advice. thank ya sir.