valve train noise issues - updated 10/11, compcam trunions installed
09-30-2012, 03:35 PM
#21
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Sunday update.
I finished buttoning up the car and drove it to bring the oil to temperature. The noise is definately less now that the stock springs are in it - though I can still hear it now that I'm tuned for it.
I pulled the rt valve cover hot and listened to the individual rockers, and I could hear the noise. I then pulled the left valve cover, maybe after sitting for 10 minutes, and the noise is very evident on #3 exhaust valve, though with the stethescope you hear it on multiple rockers. After a few minutes of listening it faded away.
On both sides I listened to the valve seats, nothing, checked for pushrod to head contact, none, tried to listen to the pushrod, you really can't, listened all over the head, nothing notable.
right side, oil hot,
Left side, oil hot
you almost can't hear the noise with the valve cover on
http://youtu.be/MVN_guq5Gew
I put .015 feeler gage under the noisiest valve on both the left and right bank, made no difference.
I pulled the oil filter and checked the mag drain plug. Nothing on the drain plug at all. The filter was clean, there were a few specs of magnetic material that I picked up on a magnet, but not what I would consider significant.
flash made this look milky, but it wasn't
I finished buttoning up the car and drove it to bring the oil to temperature. The noise is definately less now that the stock springs are in it - though I can still hear it now that I'm tuned for it.
I pulled the rt valve cover hot and listened to the individual rockers, and I could hear the noise. I then pulled the left valve cover, maybe after sitting for 10 minutes, and the noise is very evident on #3 exhaust valve, though with the stethescope you hear it on multiple rockers. After a few minutes of listening it faded away.
On both sides I listened to the valve seats, nothing, checked for pushrod to head contact, none, tried to listen to the pushrod, you really can't, listened all over the head, nothing notable.
right side, oil hot,
Left side, oil hot
you almost can't hear the noise with the valve cover on
http://youtu.be/MVN_guq5Gew
I put .015 feeler gage under the noisiest valve on both the left and right bank, made no difference.
I pulled the oil filter and checked the mag drain plug. Nothing on the drain plug at all. The filter was clean, there were a few specs of magnetic material that I picked up on a magnet, but not what I would consider significant.
flash made this look milky, but it wasn't
Last edited by mikezohsix; 09-30-2012 at 03:44 PM.
09-30-2012, 03:46 PM
#22
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I'm back to the rockers, any comments on the movement of the trunion in the video a couple of posts back?
Oil flow is the same on both sides, no metal in the oil, better with a lighter spring.
What does this add up to?
Oil flow is the same on both sides, no metal in the oil, better with a lighter spring.
What does this add up to?
09-30-2012, 04:08 PM
#23
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I ran the PAC 1218 springs as well on my stock 02 LS6. I did install new Trickflow 7.40" push rods at the same time. My valve train was dead quiet afterwords.. I drove it for 2k miles before I melted some pistons but the valve train was still quiet..
I don't think the springs are your issue.
Also my stock LS6 springs were not yellow either.. They were the normal steel color with a single orange yellow stripe. They were definitely the original springs as I got the car from the original owner who never knew there was a recall..
Maybe something with your rocker arms but... I doubt it.
I think you have a push rod problem. I had two bent pushrods when I pulled it apart for the spring swap. We never suspected anything wrong and I just did the springs for piece of mind.
I don't think the springs are your issue.
Also my stock LS6 springs were not yellow either.. They were the normal steel color with a single orange yellow stripe. They were definitely the original springs as I got the car from the original owner who never knew there was a recall..
Maybe something with your rocker arms but... I doubt it.
I think you have a push rod problem. I had two bent pushrods when I pulled it apart for the spring swap. We never suspected anything wrong and I just did the springs for piece of mind.
09-30-2012, 06:33 PM
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What else is there to a push rod?
09-30-2012, 08:12 PM
#26
This comment may not amount to a hill of beans, but I know when I did the Comp trunion upgrade in my stock rockers, the tiny bit of "slop" or side to side movement of the trunion was gone.
Maybe that's where the noise is coming from? Certainly not dead rocker trunions, but maybe a bit of slack, if that makes any sense?
Maybe that's where the noise is coming from? Certainly not dead rocker trunions, but maybe a bit of slack, if that makes any sense?
09-30-2012, 08:54 PM
#27
Mike...I am not super comfortable with how you seem to be measuring preload. You may be doing it correctly, but if you are counting turns you need to start from zero lash and I just didn't get that from your thread.
If you want to be dead nuts certain use a dial gauge at the lifter rod cup measuring from zero lash.
As loud as it is I would think you'd be able to tell if it was coming from way up high at the rockers or deeper down by the lifters...but given that the noise did not move with the rockers and I believe you had your springs checked you might have a failed lifter.
I just had one fail and I diagnosed in the motor by pushing on the lifters plungers with a pushrod. The valve was bad in one and made it softer than all the others as it wouldn't hold oilwhen compressed. GL. With your diagnosis.
If you want to be dead nuts certain use a dial gauge at the lifter rod cup measuring from zero lash.
As loud as it is I would think you'd be able to tell if it was coming from way up high at the rockers or deeper down by the lifters...but given that the noise did not move with the rockers and I believe you had your springs checked you might have a failed lifter.
I just had one fail and I diagnosed in the motor by pushing on the lifters plungers with a pushrod. The valve was bad in one and made it softer than all the others as it wouldn't hold oilwhen compressed. GL. With your diagnosis.
10-01-2012, 01:01 AM
#28
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Should the stock pushrod in that be a 7.425 length, since it is the smaller base circle Z06 cam used? If it were me, the first thing I would try would be the trunion upgrade, since if it is not that, you haven't really wasted money because you have an upgraded rocker arm either way. The next thing I would try would be a set of 7.425 pushrods. If neither of them work, and you can't live with the noise, I'd bite the bullet, buy a new set of LS7 lifters, head gaskets and head bolts. I'd pull it all down for inspection, pull the cam and take a look at it, make sure all the lobes look smooth. I've have had a lobe go bad on an LS1 cam before. If everything checks out , put it back together with the new lifters. If you were interested, this might be a good time to get your 243's ported, for an extra 40 ponies or so.
10-01-2012, 05:32 AM
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Mike...I am not super comfortable with how you seem to be measuring preload. You may be doing it correctly, but if you are counting turns you need to start from zero lash and I just didn't get that from your thread.
If you want to be dead nuts certain use a dial gauge at the lifter rod cup measuring from zero lash.
As loud as it is I would think you'd be able to tell if it was coming from way up high at the rockers or deeper down by the lifters...but given that the noise did not move with the rockers and I believe you had your springs checked you might have a failed lifter.
I just had one fail and I diagnosed in the motor by pushing on the lifters plungers with a pushrod. The valve was bad in one and made it softer than all the others as it wouldn't hold oilwhen compressed. GL. With your diagnosis.
If you want to be dead nuts certain use a dial gauge at the lifter rod cup measuring from zero lash.
As loud as it is I would think you'd be able to tell if it was coming from way up high at the rockers or deeper down by the lifters...but given that the noise did not move with the rockers and I believe you had your springs checked you might have a failed lifter.
I just had one fail and I diagnosed in the motor by pushing on the lifters plungers with a pushrod. The valve was bad in one and made it softer than all the others as it wouldn't hold oilwhen compressed. GL. With your diagnosis.
Thinking about it now I could do the same thing and wait until the lifter piston "gave", instead of getting a true reading while turning in the bolt.
I also thought about moving the rocker around from #3. I tried that early on on the right side, but the sound is more definate on the left side
I think the noise is down deep, but it is so hard to tell.
I can feel it in the rocker bolts when I'm putting the probe of the stethescope on them.
10-01-2012, 05:37 AM
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This comment may not amount to a hill of beans, but I know when I did the Comp trunion upgrade in my stock rockers, the tiny bit of "slop" or side to side movement of the trunion was gone.
Maybe that's where the noise is coming from? Certainly not dead rocker trunions, but maybe a bit of slack, if that makes any sense?
Maybe that's where the noise is coming from? Certainly not dead rocker trunions, but maybe a bit of slack, if that makes any sense?
10-01-2012, 05:45 AM
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Should the stock pushrod in that be a 7.425 length, since it is the smaller base circle Z06 cam used? If it were me, the first thing I would try would be the trunion upgrade, since if it is not that, you haven't really wasted money because you have an upgraded rocker arm either way. The next thing I would try would be a set of 7.425 pushrods. If neither of them work, and you can't live with the noise, I'd bite the bullet, buy a new set of LS7 lifters, head gaskets and head bolts. I'd pull it all down for inspection, pull the cam and take a look at it, make sure all the lobes look smooth. I've have had a lobe go bad on an LS1 cam before. If everything checks out , put it back together with the new lifters. If you were interested, this might be a good time to get your 243's ported, for an extra 40 ponies or so.
I'm going to take anther shot at measureing lifter preload, which should answer the pushrod question once and for all - it's one that's been in my head for a while.
10-01-2012, 06:53 PM
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tonight I pulled the car apart again with the oil hot.
couldn't zero in on #3 exhaust like I did yesterday.
all lifters were as hard as a rock, pushed with a big Tee handle allen wrench, nothing.
I moved rockers all over the place and really don't think the noise moved with them, but it's so hard to tell.
I did a lifter preload measurement on #1 exhaust and intake. I got .065 and .075, so preload is fine.
Think I'm going to do trunions because it's easy, then the heads come off....
couldn't zero in on #3 exhaust like I did yesterday.
all lifters were as hard as a rock, pushed with a big Tee handle allen wrench, nothing.
I moved rockers all over the place and really don't think the noise moved with them, but it's so hard to tell.
I did a lifter preload measurement on #1 exhaust and intake. I got .065 and .075, so preload is fine.
Think I'm going to do trunions because it's easy, then the heads come off....
10-01-2012, 07:13 PM
#33
Anyway, I put PAC 1518s in my bone stock 2002 Z06 and didn't hear any difference at all in valve train noise. My Z06 is pretty quiet in the valve train IMO. There is still a little "sewing machine" noise, but with the hood closed it's hard to hear. If I have the hood open and put my ear down by the valve covers I can hear a little noise. With the LS6, I don't think you will ever get rid of the noise completely. It's just the way the LS6 is, as reported by many owners. If you have an abnormal level of noise, you could really only determine that by comparing it to other engines with the same mods.
It actually doesn't sound too bad with the valve covers on (based on your posted videos). With the valve covers off it does seem like there is a slightly harsh tap up and beyond the sewing machine noise.
Last edited by ZeeOSix; 10-01-2012 at 07:38 PM.
10-11-2012, 07:51 PM
#34
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I replaced the rocker trunions with the compcam kit.
Install was very straight forward, no issues, acutally theraputic.
I'm on the stock valve springs at this point.
The car was noticably quieter right at start up.
I ran the car last night, got the oil to ~140, came back, listened, and there is nothing you can hear just by ear.
I drove the car to work and gave it a good listen to with the oil at 200. If you listen hard, you can hear something by ear, but you'd never notice it. With the stethescope you can hear something, but nothing I would ever do anything about or worry about.
I'm going to put some miles on it before I make a final judgement. If you go back to the first post you'll see that the noise started some time after the PAc1218 install, so I want to put the time on it before I say yea.
Going back you'll see a video of the play in the stock rocker trunion. There is zero play now. Below are pics of the stock parts. All trunions/bearings were in place.
The design of the stock trunion is interesting, it's a powdered metal part that does not make full contact with the inner race of the bearing (unlike the compcam parts). There was no apprecable play in the bearing inner race, but there is play between the inner race and the trunion. Interesting to me that many of the trunions have wear, not just burnishing, but actual scratches like the inner race was rotating on the trunion, which it shouldn't.
here's some pix
Install was very straight forward, no issues, acutally theraputic.
I'm on the stock valve springs at this point.
The car was noticably quieter right at start up.
I ran the car last night, got the oil to ~140, came back, listened, and there is nothing you can hear just by ear.
I drove the car to work and gave it a good listen to with the oil at 200. If you listen hard, you can hear something by ear, but you'd never notice it. With the stethescope you can hear something, but nothing I would ever do anything about or worry about.
I'm going to put some miles on it before I make a final judgement. If you go back to the first post you'll see that the noise started some time after the PAc1218 install, so I want to put the time on it before I say yea.
Going back you'll see a video of the play in the stock rocker trunion. There is zero play now. Below are pics of the stock parts. All trunions/bearings were in place.
The design of the stock trunion is interesting, it's a powdered metal part that does not make full contact with the inner race of the bearing (unlike the compcam parts). There was no apprecable play in the bearing inner race, but there is play between the inner race and the trunion. Interesting to me that many of the trunions have wear, not just burnishing, but actual scratches like the inner race was rotating on the trunion, which it shouldn't.
here's some pix
10-16-2012, 11:15 AM
#36
I did not expect to see that. I don't get into these areas regularly so I have little experience there. Now I wish I had checked mine last time I did the cam. Never thought to check this.
I guess the inner race turns easily in the trunion? Easier or same as the bearing in the race?
I was in the "bad lifter" camp. Thanks for bringing this to light.
10-17-2012, 09:03 AM
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I upgraded my rockers with the trunion kit when I did my cam install at 150K miles. It made a world of difference. A friend of mine did a cam install at the same time and he didn't upgrade the trunions and their is a noticeable difference in noise. In my mind it was worth the extra $125 for the upgrade.
10-17-2012, 06:48 PM
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I'd like to say yes, but I can't at this point.
If I feel it's acceptable after another week or so I'll put the PAC springs back on, and see what I get then.
It hasn't been bad going thru this, but it hasn't been fun either. Today I stopped ***** footing around in the car and drove it like I used to - and that's fun!
- It is much quieter.
- It doesn't have the "bad" noise that I heard at idle in the garage.
- It does still have some ticking noise that I can hear in the car at 1500 to 2000 rpm.
- I still have the original springs in it and the noise didn't get noticed until I put in the PAc 1218s.
- and I need to put more miles on it before I make a judgement.
If I feel it's acceptable after another week or so I'll put the PAC springs back on, and see what I get then.
It hasn't been bad going thru this, but it hasn't been fun either. Today I stopped ***** footing around in the car and drove it like I used to - and that's fun!
