LT4 Rocker Noise
Thread Starter
Le Mans Master
Joined: Dec 2006
Posts: 5,139
Likes: 482
From: H-Town Texas
LT4 Rocker Noise
I know that the rollers in the LT4 click a bit. However, the ticking from the rockers on #8 & maybe #6 seem to be a little louder than the others. There also seems to be a litte extra noise from that side on acceleration. I haven't noticed a performance loss, but I haven't had the car that long so I can't miss what was never there.
Back in the day, my brother had a drag racer and I remember him adjusting the rockers. So my question is could it be an adjustment issue? Do the Crane rockers lose adjustment from time to time?
I am hoping that some of you LT4 guys can help me with this. Perhaps this is just the way the LT4 sounds. If so I can live with it. BTW, the car has about 37k.
Back in the day, my brother had a drag racer and I remember him adjusting the rockers. So my question is could it be an adjustment issue? Do the Crane rockers lose adjustment from time to time?
I am hoping that some of you LT4 guys can help me with this. Perhaps this is just the way the LT4 sounds. If so I can live with it. BTW, the car has about 37k.
Race Director
Joined: Dec 2002
Posts: 13,348
Likes: 233
From: SCMR Rat Pack'r Charter Member..Great Bend KS
LT4's, like the LT1, have hydraulic lifters. This means the valvetrain should never need adjusting.
This also means that if you are getting rocker or lifter noise, then something is amiss and should be looked at....normally they are quiet.
Larry
code5coupe
PS Be seeing you soon, lt4ob. I and the Vette are moving to Great Bend in November.
__________
I ain't easily impressed....
This also means that if you are getting rocker or lifter noise, then something is amiss and should be looked at....normally they are quiet.
Larry
code5coupe
PS Be seeing you soon, lt4ob. I and the Vette are moving to Great Bend in November.
__________
I ain't easily impressed....
Last edited by rocco16; Apr 13, 2007 at 10:43 AM.
Instructor
Joined: Dec 2006
Posts: 114
Likes: 0
From: Florida
mine does it but only when its cold...its not loud but you can still hear it an when your acceleratin it gets louder..thats whem my cars -120degress..when its 120+ it stops..does your car do it at any temp?
Melting Slicks
Joined: Apr 2003
Posts: 2,150
Likes: 6
From: NS
I know that the rollers in the LT4 click a bit. However, the ticking from the rockers on #8 & maybe #6 seem to be a little louder than the others. There also seems to be a litte extra noise from that side on acceleration. I haven't noticed a performance loss, but I haven't had the car that long so I can't miss what was never there.
Back in the day, my brother had a drag racer and I remember him adjusting the rockers. So my question is could it be an adjustment issue? Do the Crane rockers lose adjustment from time to time?
I am hoping that some of you LT4 guys can help me with this. Perhaps this is just the way the LT4 sounds. If so I can live with it. BTW, the car has about 37k.
Back in the day, my brother had a drag racer and I remember him adjusting the rockers. So my question is could it be an adjustment issue? Do the Crane rockers lose adjustment from time to time?
I am hoping that some of you LT4 guys can help me with this. Perhaps this is just the way the LT4 sounds. If so I can live with it. BTW, the car has about 37k.
So as a test I upped my oil viscosity to 5w50 Syntec and it was MUCH better. So I figured I had a couple of bad lifters. Now the intake is off and a set of brand new lifters are going in. Hopefully it will cure the problem. I'll post back with how it goes. Remind me if I forget.
Last edited by Atok; Apr 13, 2007 at 10:36 PM.
Thread Starter
Le Mans Master
Joined: Dec 2006
Posts: 5,139
Likes: 482
From: H-Town Texas
Now, I want to be sure that I am not overstating the "problem". I cannot hear any of this from the cockpit, only with the hood up standing over the engine. It's not setting off the knock sensor or anything like that. In fact I am probably just paranoid that there is one or two horses that I might be missing out on.
Thanks for your help. I believe that it appears everything is normal. If I discover a problem I will post it so that others may know as well.
Thanks for your help. I believe that it appears everything is normal. If I discover a problem I will post it so that others may know as well.
Melting Slicks
Joined: Apr 2003
Posts: 2,150
Likes: 6
From: NS
Yep, that's how mine is. Can't hear it from sitting in the driver's seat, or even when standing on the left side of the car. Mine only sets the knock sensor off when the oil is hot, and I hold the RPM around 1800 or so in neutral. Yes, it sounds "normal" to me, just louder than it should be.
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Pro
Joined: Nov 2005
Posts: 536
Likes: 0
From: Bardstown Kentucky
Now, I want to be sure that I am not overstating the "problem". I cannot hear any of this from the cockpit, only with the hood up standing over the engine. It's not setting off the knock sensor or anything like that. In fact I am probably just paranoid that there is one or two horses that I might be missing out on.
Thanks for your help. I believe that it appears everything is normal. If I discover a problem I will post it so that others may know as well.
Thanks for your help. I believe that it appears everything is normal. If I discover a problem I will post it so that others may know as well.
Intermediate
Joined: Oct 2006
Posts: 41
Likes: 0
From: West Chester PA
Funny thing is I put LT4 rockers on my LT1 about a year ago. Since doing this I have had this annoying valve noise on #8 and #6 just like you said. Not really a tick but a very mechanical noticeable noise. Left side is very quiet. I switched rockers from left to right, no difference. I tried different valve lash settings, no difference. When the engine is hot it's enough to trip the knock sensor at just the right RPM sitting in my garage in neutral! If it wasn't for this I wouldn't mind it so much. Using an LT4 KM it is much worse (more false knock).
So as a test I upped my oil viscosity to 5w50 Syntec and it was MUCH better. So I figured I had a couple of bad lifters. Now the intake is off and a set of brand new lifters are going in. Hopefully it will cure the problem. I'll post back with how it goes. Remind me if I forget.
So as a test I upped my oil viscosity to 5w50 Syntec and it was MUCH better. So I figured I had a couple of bad lifters. Now the intake is off and a set of brand new lifters are going in. Hopefully it will cure the problem. I'll post back with how it goes. Remind me if I forget.
How did the lifter change go ? Did it fix the noise ? I have a very similar situation.
Large Impressive Member
Joined: Jul 2003
Posts: 65,811
Likes: 71
From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Now, I want to be sure that I am not overstating the "problem". I cannot hear any of this from the cockpit, only with the hood up standing over the engine. It's not setting off the knock sensor or anything like that. In fact I am probably just paranoid that there is one or two horses that I might be missing out on.
Thanks for your help. I believe that it appears everything is normal. If I discover a problem I will post it so that others may know as well.
Thanks for your help. I believe that it appears everything is normal. If I discover a problem I will post it so that others may know as well.
Advanced
Joined: Nov 2006
Posts: 61
Likes: 0
From: Oak Hills Ca
Not to scare anyone but I had a 1996 LT1 with about 93,000 mile and started to get a little lifter noise. That soon turn into a cherping sound. sounded like a bird under the hood. Track down the noise to the number 7 cylinder vavle train. The roller on the lifter had developed pitts and nicks all the way around it the cam felt smooth but it was hard to tell if it was damaged. I changed it out and have put about 700 mile and with no issues. I am keeping my fingers crossed that it does not come back.
Perry
Perry
Safety Car
Joined: May 2005
Posts: 4,176
Likes: 7
From: Jennings LA
fuel injectors?
are you sure it is not the fuel injector ticking? thats what mine was, sounded just like a bad lifter. get a listening device ie: long screwdriver or piece of heater hose and put it on the injectors 
Large Impressive Member
Joined: Jul 2003
Posts: 65,811
Likes: 71
From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Not to scare anyone but I had a 1996 LT1 with about 93,000 mile and started to get a little lifter noise. That soon turn into a cherping sound. sounded like a bird under the hood. Track down the noise to the number 7 cylinder vavle train. The roller on the lifter had developed pitts and nicks all the way around it the cam felt smooth but it was hard to tell if it was damaged. I changed it out and have put about 700 mile and with no issues. I am keeping my fingers crossed that it does not come back.
Perry
Perry
Can I assume that you eyeballed the cam lobe all the way around and it looked okay? If so then you may be fine. I've seen isolated roller issues on HD diesels that looked similar and the cam survived. Other times it didn't. Sometimes it could be assumed to be a quality variance in the metal composistion of the roller. In some engines though it would become fairly common and a design change of the roller would soon follow. The LT1 lifters have an excellent record for long life so let's hope it's an isolated situation and that all is well.
Advanced
Joined: Nov 2006
Posts: 61
Likes: 0
From: Oak Hills Ca
I was not able to look into the lifter hole.
But I did carefully stick my finger in there and rotated the engine over while trying to feel the lobe. It felt smooth. It was just this one lifter.
Like I said I'm keeping my fingers cross that it doesn't come back. But if it does i know what will need to be done. (Time for Full rebuild)
Perry
But I did carefully stick my finger in there and rotated the engine over while trying to feel the lobe. It felt smooth. It was just this one lifter.
Like I said I'm keeping my fingers cross that it doesn't come back. But if it does i know what will need to be done. (Time for Full rebuild)
Perry
Melting Slicks
Joined: Apr 2003
Posts: 2,150
Likes: 6
From: NS
Melting Slicks
Joined: Sep 2003
Posts: 2,270
Likes: 118
From: N. Babylon NY
It sounds like it coming from the engine (valve cover). With just over 100,000 miles and tracked 2-4 times a season changing them is not a bad thing. I also read here that it could be the fuel injectors-but in my case it sounds like a valve train noise.
Thanks,
Steven