LT4 Valvetrain Noise
Thread Starter
Heel & Toe
Joined: Aug 2001
Posts: 18
Likes: 1
From: Lancaster NY
LT4 Valvetrain Noise
I am experiencing valvetrain noise in my car and I am unsure of how to determine what is the cause. The noise has been intermittent since I purchased the car. I can’t pinpoint any special circumstances under which it occurs. Sometimes I’m unable to hear it in the car, sometimes I can barely hear it and sometimes I can hear it loud and clear. It does seem to be louder at idle, however it may get drowned out during higher revs. During a Hot Cam install, I rolled the push rods across a piece of glass to see if they were bent and they did not appear to be. I’ve checked the torque on the rockers and they are ok. Therefore, I’m not sure if the lifters are creating a problem, or if the lack of adjustability on the rocker arms is to blame.
Thanks for any help!
Kirk
Thanks for any help!
Kirk
Race Director
Joined: Jul 2000
Posts: 11,007
Likes: 1
From: Probably in the paint booth....
Re: LT4 Valvetrain Noise (motorhead1996)
Mine is loud as hell also. Everyone I have talked to that has heard it says it's the injectors.
Neal
Edited: for spelling errors :rolleyes:
[Modified by Arisa, 1:48 PM 10/9/2002]
Neal
Edited: for spelling errors :rolleyes:
[Modified by Arisa, 1:48 PM 10/9/2002]
Safety Car
Joined: Jun 1999
Posts: 3,570
Likes: 3
From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
Re: LT4 Valvetrain Noise (fullboogie)
Mine is quiet. Usually, its one or more of the injectors.
I am not sure why roller rockers in general would be noisier than stock stamped rockers. Both have hydraulic lifters, which should remove all the slack in either case.
[Modified by Mez, 2:49 PM 10/10/2002]
I am not sure why roller rockers in general would be noisier than stock stamped rockers. Both have hydraulic lifters, which should remove all the slack in either case.
[Modified by Mez, 2:49 PM 10/10/2002]
Melting Slicks
Joined: Jun 2000
Posts: 3,215
Likes: 6
From: Tampa Florida
Re: LT4 Valvetrain Noise (motorhead1996)
Have you considered an exhaust leak?
I'm pretty sure I have a small one that comes and goes depending on how hard it has been run or temperature. I swapped the complete valvetrain and still have the tick from previous, but I never disturbed the exhaust manifolds...they will come off this winter:)
Otherwise my HOT cam is just as quiet as stock...are your valves adjusted correctly? 1 turn down from 0 preload? I have tried the engine off static adjustment of the lifters and that never works for me-close until I can to the warm running engine adjustment, but not good enough to leave alone for sure.
:)
I'm pretty sure I have a small one that comes and goes depending on how hard it has been run or temperature. I swapped the complete valvetrain and still have the tick from previous, but I never disturbed the exhaust manifolds...they will come off this winter:)
Otherwise my HOT cam is just as quiet as stock...are your valves adjusted correctly? 1 turn down from 0 preload? I have tried the engine off static adjustment of the lifters and that never works for me-close until I can to the warm running engine adjustment, but not good enough to leave alone for sure.
:)
Cruising
Joined: Oct 2002
Posts: 12
Likes: 0
From: Atlanta GA
Re: LT4 Valvetrain Noise (motorhead1996)
Kirk-
Can you describe this sound a little more. My Lt4 seems to be making a sound that is on again/off again. Seems the loudest at startup and then quiets down. My sound is a ticking of some kind. Anyone else help us noisy Lt4s out? :confused: By the way, my engine is stock.
Brian
[Modified by Katfaiia, 2:47 AM 10/10/2002]
Can you describe this sound a little more. My Lt4 seems to be making a sound that is on again/off again. Seems the loudest at startup and then quiets down. My sound is a ticking of some kind. Anyone else help us noisy Lt4s out? :confused: By the way, my engine is stock.
Brian
[Modified by Katfaiia, 2:47 AM 10/10/2002]
Pro
Joined: Sep 2002
Posts: 500
Likes: 0
From: Mississauga ONT
Re: LT4 Valvetrain Noise (Katfaiia)
im prety sure what it is. its a lifter. Which doesnt nessesarily mean a bad thing. At low revs or startup theres no oil to fill it and it will click. But at higher revs it goes away. My car when drivign slow then to a stop when its hot , its loudest then. Click click tick tick. tick tick tick tick
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Thread Starter
Heel & Toe
Joined: Aug 2001
Posts: 18
Likes: 1
From: Lancaster NY
Re: LT4 Valvetrain Noise (388 SOLid RoLLeR)
I called Crane Cams Tech Line figuring that since they made the roller rockers, they might be able to point me in a direction. Their first suggestion was at the next oil change, use a quart of Rislone instead of one quart of oil. They said that this should remove any dirt or sludge that may be in the lifters preventing proper oil flow. If that doesn't work, the next thought was to replace the lifters. However, as the rockers aren't adjustable, he said that I could check the preload on the lifters to ensure that they are adjusted properly. Apparently the correct preload is 0.020-0.060". Then depending on the outcome, replace the lifters or rockers. I think that I'll do an oil change to try the Rislone $4 fix, but I'm not going to hold my breath.
As far as what the noise sounds like, I believe that it is too heavy to be an exhaust leak. Depending on what day it is, the noise varies from a subtle tick tick to a heavy clack clack. No noise at startup this morning, but I wouldn't be surprised if it got noisy at lunch.
As far as what the noise sounds like, I believe that it is too heavy to be an exhaust leak. Depending on what day it is, the noise varies from a subtle tick tick to a heavy clack clack. No noise at startup this morning, but I wouldn't be surprised if it got noisy at lunch.
Burning Brakes
Joined: Feb 2002
Posts: 871
Likes: 1
From: Union KY
Re: LT4 Valvetrain Noise (motorhead1996)
Motorhead:
My LT4 (56,000 miles) has always had a bit of what sounds like valve clatter at start up. But none after everything gets oiled. I agree witht he earlier post that you need to adjust the valves hot. I have never gotten all cylinders right with a static adjustment. Somehow, there's always one valve that fails to cooperate. Cire96
My LT4 (56,000 miles) has always had a bit of what sounds like valve clatter at start up. But none after everything gets oiled. I agree witht he earlier post that you need to adjust the valves hot. I have never gotten all cylinders right with a static adjustment. Somehow, there's always one valve that fails to cooperate. Cire96
Burning Brakes
Joined: Aug 2002
Posts: 848
Likes: 0
From: Houston TX
Re: LT4 Valvetrain Noise (Mez)
I am not sure why roller rockers in general would be noisier than stock stamped rockers. The both hydraulic lifters which should remove all the slack in either case.
