question re: valve train noises that dont seem normal.
Thread Starter
Joined: May 2004
Posts: 1,080
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From: Elgin, Illinois
well i put my buddies rockers on today and they did the same thing. I noticed his had the same amount of play. I have one question about preload and pushrod play. I used a dial on a few valves and had about .100" preload. However i noticed this AM when i put the other rockers on and torqued them to 22 ft/lbs, the pushrod would rotate a tad. Not alot and with quite a bit of effort required, is this normal?
Also, again the noise didnt start right away. It didnt occur until oil temp was about 95 deg or so then it gradually started to get a bit louder till it hit its normal sound. I noticed even though the oil pressure was 50 psi it was occuring. I think its safe to say its not an oil pressure problem.
Im out of ideas now..
Dave
Also, again the noise didnt start right away. It didnt occur until oil temp was about 95 deg or so then it gradually started to get a bit louder till it hit its normal sound. I noticed even though the oil pressure was 50 psi it was occuring. I think its safe to say its not an oil pressure problem.
Im out of ideas now..
Dave
Teching In
Joined: Jul 2005
Posts: 15
Likes: 2
From: Sunny Florida
Originally Posted by TT_Vert
i figured if it was a bearing problem, killing a cylinder would change the pitch some. I killed all 8 the pitch didnt change a bit.
Dave
Dave
Thread Starter
Joined: May 2004
Posts: 1,080
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From: Elgin, Illinois
i would be able to visually ID a cracked boss id assume? I can check that certainly but it seems to be happening on both sides so i dont know if that is the problem. I could put the oem heads back on and that very well may be the next step. Not really what i wanted to do but its an option.
Dave
Dave
Teching In
Joined: Jul 2005
Posts: 15
Likes: 2
From: Sunny Florida
Originally Posted by TT_Vert
i would be able to visually ID a cracked boss id assume? I can check that certainly but it seems to be happening on both sides so i dont know if that is the problem. I could put the oem heads back on and that very well may be the next step. Not really what i wanted to do but its an option.
Dave
Dave
I think I would put the oem heads back on before considering pulling the pan to change the bearings. You've done all the requisite steps in determining rod knocks/wrist pins: killing the cylinder, changing oil weight, etc and it really sounds like it's an upper engine problem. If the noise is still there with the stock heads, you can eliminate the heads, rockers (since you tried your buddy's rockers), valves, pushrods (you tried new ones with no luck), springs, etc. You'd be left with the cam, lifters and or rod bearings. BUT if the noise goes away..........
I'm really considering updating my heads and using the same cam but I'm waiting to find out the results of your dilemma before taking the plunge.
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Verdad Gallardo Thread Starter
Joined: May 2004
Posts: 1,080
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From: Elgin, Illinois
. I pulled the front cover off, checked the back of the car gear for any contact and that cam retainer plate/seal for wear and both looked fine. Does anyone know how the lifters receive their oil/ It seems that front cam retainer just seals a passage from one bank lifter oiling passage to the other.
Dave
Dave
Thread Starter
Joined: May 2004
Posts: 1,080
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From: Elgin, Illinois
yes very. i cant even put my stock heads back on w/o swapping the springs over due to coil bind. SO if the noise does occur, it dosent eliminate the springs as a posibility
dave
dave
If you have some $$$ in your budget, get some aftermarket rockers (HS or Yella-Terra) and see if it helps...To me it really sounds like a rocker problem...
Just make sure you check the geometry with the new setup...
Just make sure you check the geometry with the new setup...
Thread Starter
Joined: May 2004
Posts: 1,080
Likes: 0
From: Elgin, Illinois
i really dont have the money but if i could be certain it was the problem, they would be in there. I put some other OEM rockers in and they made the same sound. What id like to do is find someone to let me borrow some for an hour to test that theory but i know that'll never happen.
Dave
Dave
Thread Starter
Joined: May 2004
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From: Elgin, Illinois
update #99,233. I replaced the cam retaining plate just to make sure enough oil was getting to the lifters and it didnt do a thing. I decided to brake torque it and the noise seems to go away. The problem is its 6 spd and the noise usually occurs around 2500ish. the ebrake cant hold the car really so its hard to tell for sure but im pretty certain the noise is completely gone when i brake torqued it. Which would make sense since i dont seem to hear it WOT next to a wall either. It'll come back the second i let off the gas though.
Dave
Dave
Are you still running AIR tubes? If so, block off the tubes and recheck.
__________________
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
I was just thinking about your comment. You said the clattering went away at when brake torqued and at WOT but came back at decel. I'm just reaching here, but I'm trying to look for something...anything!
An exhaust leak might get louder at WOT, but what about the PCV system? When messed up, they can get louder at decel and can magnify valvetrain noise. Think of everything that happens only at high vacuum signals. That might lead you closer to your problem.