Rec'c for 'quiet' rockers?
Thread Starter
Race Director
Joined: Jun 2013
Posts: 12,406
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From: DFW TX
Rec'c for 'quiet' rockers?
Looking to quiet down the sewing machine noise.
Engine is 'built' LS2 based 427, done by MTI Motorsports maybe 10yrs ago. Stock rockers with BTR trunnion on a healthy though not extreme cam, makes a fair amount of sewing machine noise. Running M1 0W40.
Any rec's for 'bolt on' rockers? I don't mind measuring, shimming, ordering new pushrods etc. But I do not want to have to remove the heads or do machine work. I rev the engine to only 6500, nothing super fancy needed. There's a zillion out there, my research has not really honed in on any particular rocker. Any input appreciated!
in advance
Engine is 'built' LS2 based 427, done by MTI Motorsports maybe 10yrs ago. Stock rockers with BTR trunnion on a healthy though not extreme cam, makes a fair amount of sewing machine noise. Running M1 0W40.
Any rec's for 'bolt on' rockers? I don't mind measuring, shimming, ordering new pushrods etc. But I do not want to have to remove the heads or do machine work. I rev the engine to only 6500, nothing super fancy needed. There's a zillion out there, my research has not really honed in on any particular rocker. Any input appreciated!
in advance
Le Mans Master
Joined: Jul 2010
Posts: 5,972
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Looking to quiet down the sewing machine noise.
Engine is 'built' LS2 based 427, done by MTI Motorsports maybe 10yrs ago. Stock rockers with BTR trunnion on a healthy though not extreme cam, makes a fair amount of sewing machine noise. Running M1 0W40.
Any rec's for 'bolt on' rockers? I don't mind measuring, shimming, ordering new pushrods etc. But I do not want to have to remove the heads or do machine work. I rev the engine to only 6500, nothing super fancy needed. There's a zillion out there, my research has not really honed in on any particular rocker. Any input appreciated!
in advance
Engine is 'built' LS2 based 427, done by MTI Motorsports maybe 10yrs ago. Stock rockers with BTR trunnion on a healthy though not extreme cam, makes a fair amount of sewing machine noise. Running M1 0W40.
Any rec's for 'bolt on' rockers? I don't mind measuring, shimming, ordering new pushrods etc. But I do not want to have to remove the heads or do machine work. I rev the engine to only 6500, nothing super fancy needed. There's a zillion out there, my research has not really honed in on any particular rocker. Any input appreciated!
in advance
Thread Starter
Race Director
Joined: Jun 2013
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From: DFW TX
Team Owner
Joined: May 2001
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From: Western NY
True, but if I understand correctly, the OP stated he didn't want to pull the heads, and don't you have to pull the heads, to remove the lifters from their "buckets" on an LS series engine?
Safety Car
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From: Wisconsin
I have Harland Sharp rollors on my Trick flow heads, only because T.F recommends using a roller rocker. My car has the sewing machine noise also. With headers, cam I don't think you can get away from it.
Team Owner
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From: Western NY
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Melting Slicks
Joined: Dec 2004
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From: Dallas TX
rockers will NOT quiet down the sewing machine.
The ticking is a combination of valves closing quickly due to cam ramp rates and high rate springs(this is likely the majority of it), lifters ticking as they unload, and probably a few other factors... Adding a touch of pre-load to the lifters via slightly longer push rods can help A LITTLE, but for the most part, that sewing machine tick is what it is.
IF this is a newer "tick", then your lifters are likely losing their spring pressure and thus your pre-load is way low.
The ticking is a combination of valves closing quickly due to cam ramp rates and high rate springs(this is likely the majority of it), lifters ticking as they unload, and probably a few other factors... Adding a touch of pre-load to the lifters via slightly longer push rods can help A LITTLE, but for the most part, that sewing machine tick is what it is.
IF this is a newer "tick", then your lifters are likely losing their spring pressure and thus your pre-load is way low.
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Thread Starter
Race Director
Joined: Jun 2013
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From: DFW TX
the engine previously had Jessel rockers, PO installed these rockers more recently. I will pull one and check. Is there a “good” trunnion currently?
Good to know, I was under the impression the noise could be reduced via roller rockers. It is not a new noise, very consistent in the time I’ve had the car, and actually pretty quiet versus some engines I’ve heard. Just not a “nice” noise and I’d like to reduce it if reasonably possible.
No clicking or ticking, just a good sewing machine noise.
rockers will NOT quiet down the sewing machine.
The ticking is a combination of valves closing quickly due to cam ramp rates and high rate springs(this is likely the majority of it), lifters ticking as they unload, and probably a few other factors... Adding a touch of pre-load to the lifters via slightly longer push rods can help A LITTLE, but for the most part, that sewing machine tick is what it is.
IF this is a newer "tick", then your lifters are likely losing their spring pressure and thus your pre-load is way low.
The ticking is a combination of valves closing quickly due to cam ramp rates and high rate springs(this is likely the majority of it), lifters ticking as they unload, and probably a few other factors... Adding a touch of pre-load to the lifters via slightly longer push rods can help A LITTLE, but for the most part, that sewing machine tick is what it is.
IF this is a newer "tick", then your lifters are likely losing their spring pressure and thus your pre-load is way low.
No clicking or ticking, just a good sewing machine noise.
Last edited by acroy; Dec 28, 2020 at 02:31 PM.
Melting Slicks
Joined: Dec 2004
Posts: 2,649
Likes: 631
From: Dallas TX
Good to know, I was under the impression the noise could be reduced via roller rockers. It is not a new noise, very consistent in the time I’ve had the car, and actually pretty quiet versus some engines I’ve heard. Just not a “nice” noise and I’d like to reduce it if reasonably possible.
No clicking or ticking, just a good sewing machine noise.
No clicking or ticking, just a good sewing machine noise.
Its generally tied back to the valve ramp rates on the cam. Newer cams have some different ramps to try to combat this to some effect that werent available years ago. They have a fast open and fast close but JUST before the valve closes they really slow things down. Or they fast open, but can slow close. Also newer valve spring design where they can control the valve with less spring pressure needed.
So possibly looking into swapping the cam to a newer design with some different lobes, newer double valve springs, maybe a SLIGHTLY longer push rod to add a little more pre-load to the lifter, a move away from the LS7 lifters(if thats what your motor has in it) to something like a Johnson short travel(MUCH higher quality)... Its a lot of money to chase a tick that if it hasnt gotten any worse and IMO is "normal" probably isnt causing any harm to the motor.
I dont believe going to a roller rocker is going to do much of anything for you...
Thread Starter
Race Director
Joined: Jun 2013
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From: DFW TX
I know the LS7 is notorious for it.
Its generally tied back to the valve ramp rates on the cam. Newer cams have some different ramps to try to combat this to some effect that werent available years ago. They have a fast open and fast close but JUST before the valve closes they really slow things down. Or they fast open, but can slow close. Also newer valve spring design where they can control the valve with less spring pressure needed.
So possibly looking into swapping the cam to a newer design with some different lobes, newer double valve springs, maybe a SLIGHTLY longer push rod to add a little more pre-load to the lifter, a move away from the LS7 lifters(if thats what your motor has in it) to something like a Johnson short travel(MUCH higher quality)... Its a lot of money to chase a tick that if it hasnt gotten any worse and IMO is "normal" probably isnt causing any harm to the motor.
I dont believe going to a roller rocker is going to do much of anything for you...
Its generally tied back to the valve ramp rates on the cam. Newer cams have some different ramps to try to combat this to some effect that werent available years ago. They have a fast open and fast close but JUST before the valve closes they really slow things down. Or they fast open, but can slow close. Also newer valve spring design where they can control the valve with less spring pressure needed.
So possibly looking into swapping the cam to a newer design with some different lobes, newer double valve springs, maybe a SLIGHTLY longer push rod to add a little more pre-load to the lifter, a move away from the LS7 lifters(if thats what your motor has in it) to something like a Johnson short travel(MUCH higher quality)... Its a lot of money to chase a tick that if it hasnt gotten any worse and IMO is "normal" probably isnt causing any harm to the motor.
I dont believe going to a roller rocker is going to do much of anything for you...
I have some thinking how far the rabbit hole I want to go - the engine has been very reliable and healthy, 550whp on conservative 91tune. It is tempting to re-do cam, valvetrain, maybe even heads with all the 'new' goodies out there such as the clever cam profiles you mention... Gain 50+hp and maybe have a quieter engine as well.
In the meantime. this thread stopped me from spending money on a part that won't do what I wanted it to do
I don't know what lifters are in there, that did not come with the documentation, I assume whatever was standard in a build such as this in 2010 or thereabouts.
Team Owner
Joined: May 2001
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From: Western NY
I've got to agree with you, on this. Several years back, when the scare about the OE trunnions spitting out their needles "hit the street", even though I don't race, or drive really hard, I switched to the Comp Cams trunnion/bearing set up. While this may have improved my reliability, the car still had the "sewing machine" sound. I then decided to try the "bushings" that Straub Technology offered. Long story short, the engine got noticeably quieter.
Burning Brakes
Joined: Feb 2019
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From: SW Ohio
My first Z06 had a Breathless Performance Heads and Cam package on it that was installed in 2005 and it sounded like an industrial sewing machine. It was very reliable and never had an issue but I ALWAYS hated the noise. Fast forward to my current Z06 and with a smith brothers trunion kit, a TSP cam (233/239), TSP 225 heads, and Morel lifters it is amazingly quiet and the injectors are the loudest part of the motor. I was anticipating a noisy motor and am shocked at how quiet it ended up being. I initially attributed it to the lifters, but I think in the end it’s just the totality of all the geometry. I also wrapped my headers this go around and that may contribute to the quiet valves also.
Last edited by CinciZ06; Dec 28, 2020 at 10:04 PM.
Thread Starter
Race Director
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From: DFW TX
I've got to agree with you, on this. Several years back, when the scare about the OE trunnions spitting out their needles "hit the street", even though I don't race, or drive really hard, I switched to the Comp Cams trunnion/bearing set up. While this may have improved my reliability, the car still had the "sewing machine" sound. I then decided to try the "bushings" that Straub Technology offered. Long story short, the engine got noticeably quieter.
My first Z06 had a Breathless Performance Heads and Cam package on it that was installed in 2005 and it sounded like an industrial sewing machine. It was very reliable and never had an issue but I ALWAYS hated the noise. Fast forward to my current Z06 and with a smith brothers trunion kit, a TSP cam (233/239), TSP 225 heads, and Morel lifters it is amazingly quiet and the injectors are the loudest part of the motor. I was anticipating a noisy motor and am shocked at how quiet it ended up being. I initially attributed it to the lifters, but I think in the end it’s just the totality of all the geometry. I also wrapped my headers this go around and that may contribute to the quiet valves also.