Excessive valvetrain noise... potential causes?
Thread Starter
Melting Slicks
Joined: Feb 2002
Posts: 2,285
Likes: 2
From: Crooks SD
Excessive valvetrain noise... potential causes?
I have a built shortblock topped off with Patriot 'LS6 style' heads and dual springs. Cam is a G5x3, push rods are 7.4" (I believe, will have to verify... but assume this is accurate.)
Since the heads have supposedly been milled to 59cc, can I assume I'll need to have a shorter pushrod? I believe the stock length is 7.4" and most go with a 7.350" with milled heads.
Opinions?
Since the heads have supposedly been milled to 59cc, can I assume I'll need to have a shorter pushrod? I believe the stock length is 7.4" and most go with a 7.350" with milled heads.
Opinions?
Tech Contributor
Joined: Apr 2007
Posts: 10,924
Likes: 77
From: Forney Texas
For proper valve control and the least noise, it will be worthwhile for you to purchase a pushrod length checker, measure and then order. Guessing is not the way to go. There are way too many variables to just ask. You could go with "the norm", but keep in mind that when you have valvetrain noise, you're going to be doing what I'm telling you and trying to sell your used pushrods.
Thread Starter
Melting Slicks
Joined: Feb 2002
Posts: 2,285
Likes: 2
From: Crooks SD
I do not know for sure, to be honest. The previous owner went into the motor... not myself.
However, after reviewing sellers threads, I do not find any indication they were other than stock.
However, after reviewing sellers threads, I do not find any indication they were other than stock.
Melting Slicks
Joined: May 2003
Posts: 2,851
Likes: 1
From: San Bruno Ca
then the lifters should be fine. I have a set of Trick flow chromemoly pushrods that are 7.350 length with les than 100 miles on them, le me know if you need them. $50.00 shipped.
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Racer
Joined: Apr 2008
Posts: 265
Likes: 0
From: Wesley Chapel Florida
I read this post earlier today and it was in my plans to change the oil in the vette today so I tried something a tad different. I really can't stand the "sewing maching" sound from my car after the head, cam, header change, so when I changed my oil I used a quart of the Lucas synthetic oil stabilizer along with Mobil 1 10W-30 synthetic for the sole purpose of seeing if it would get rid of some of the valve train noise. I have used the Lucas in my '04 F150 and I love it since I have 128,000 on that truck and it runs like the day it was born, so I wanted to see if it had any effect on the vette. Well, it didn't. The sound is exactly the same as before. I used the pushrod length checker, and with my ported and milled 243's the pushrod length was 7.400. My cam is a Comp 237/241 on a 111+4 and the difference from stock was very noticeable and I don't like the noise, but it appears that it is staying.
Racer
Joined: Jan 2006
Posts: 415
Likes: 1
From: Ft. Wayne In
Patriot does not mill their heads,they weld fill and then CNC the chamber to spec.I have their 59cc heads and have done every measurement,shimmed the rockers etc. etc. and have found that unless the lifters are preloaded almost until they are bottomed out there is noise.I have changed cams in about a dozen LS motors and they all have the sewing machine sound.I wouldn't run an incorrect valvetrain geometry just to eliminate the noise.
Safety Car
Joined: Oct 2004
Posts: 4,816
Likes: 132
From: Plano TX
I have a 02 Z with the Ls6.. These motors all sound like a sewing machine on and off.. nature of the beast... My stock 99 Ls1 did not make a sound except for the piston slap during warm up. Just for kicks go do an advanced search on this web site.. ADVANCED SEARCH... then type in SEWING MACHINE .... You will agree its perfectly normal if you want to go ahead and read 1000 posts on this subject.. I'll just save you some time
Last edited by David426; Nov 22, 2008 at 04:25 PM.
Thread Starter
Melting Slicks
Joined: Feb 2002
Posts: 2,285
Likes: 2
From: Crooks SD
I had a '99 before, but the heads/cam were stock. I ran Comp 918's and it barely made a sound (with FLP long tubes, cats, SLP loudmouth). Granted, this is a built-bottom end and ported 'stock' heads, but it's FAR louder.
regardless, I guess I'll leave it be.
regardless, I guess I'll leave it be.
Le Mans Master
Joined: Nov 2007
Posts: 7,683
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From: La La land cali
St. Jude Donor '09
I don't know how many times I have been told this 
it is reassuring though!
My stock LS1 2000 vert was as quiet as a mouse. My 02 Z is taking some "getting used to" 
it is reassuring though!
Le Mans Master
Joined: Jul 2005
Posts: 7,121
Likes: 3
From: Shreveport/Bossier Louisiana
St. Jude Donor '08
I dont think thats an accurate statement. I was told this a long time ago but then a well known tuner was honest and said that it is possible to not have the sewing maching noise if you take the time to measure the pushrod length. Most tuners just sell the standard 7.4" pushrods with their kits because, honestly, everyones setup is going to be different. Mine was loud with the 7.4" but is very nice now with 7.325"
Le Mans Master
Joined: Jun 2006
Posts: 6,979
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From: Wichita KS
I dont think thats an accurate statement. I was told this a long time ago but then a well known tuner was honest and said that it is possible to not have the sewing maching noise if you take the time to measure the pushrod length. Most tuners just sell the standard 7.4" pushrods with their kits because, honestly, everyones setup is going to be different. Mine was loud with the 7.4" but is very nice now with 7.325"
Team Owner
Joined: May 2001
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From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
To one degree or another, most LSx engines suffer from this; sometimes even in stock form. Sometimes fuel injector noise can add to the overall noise factor too. My stock '99 LS1 engine had some of it.A couple things I have noticed over the last several years is the re-location of the knock sensors to the sides of the block (away from cam/lifter noise presumably) starting with the LS2s, and now the LS3 has a pre-molded foam liner on the underside of coil covers on that engine.
Le Mans Master
Joined: Apr 2005
Posts: 8,077
Likes: 4
From: Scarborough ONTARIO
To one degree or another, most LSx engines suffer from this; sometimes even in stock form. Sometimes fuel injector noise can add to the overall noise factor too. My stock '99 LS1 engine had some of it.A couple things I have noticed over the last several years is the re-location of the knock sensors to the sides of the block (away from cam/lifter noise presumably) starting with the LS2s, and now the LS3 has a pre-molded foam liner on the underside of coil covers on that engine.
Team Owner
Joined: May 2001
Posts: 36,836
Likes: 244
From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
On my LS2 block, my ('99) OEM KS's were screwed into existing threaded holes on the sides, just aft of the motor mounts. This is where the KS's mount on LS2s anyways.
I am not positive if the LS1/6 blocks have these pre-threaded unused holes that can be used as well. I've also heard some mention of tapping required, but maybe that was because they were using a different hole on the side of the block. Since I did not perform the work myself, I can't speak to the LS1/6 blocks. I would THINK they (holes) would be there however.
There are readily available wiring harness plug-n-play adapter harnesses available that give enough length for each side to be able to plug into your existing connector. As far as I know this would be something that Casper's Electronics offers.
HTH
I am not positive if the LS1/6 blocks have these pre-threaded unused holes that can be used as well. I've also heard some mention of tapping required, but maybe that was because they were using a different hole on the side of the block. Since I did not perform the work myself, I can't speak to the LS1/6 blocks. I would THINK they (holes) would be there however.
There are readily available wiring harness plug-n-play adapter harnesses available that give enough length for each side to be able to plug into your existing connector. As far as I know this would be something that Casper's Electronics offers.
HTH