valvetrain noise 5.9 magnum

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pjc360

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Today I noticed some noise coming from my engine while it was at an idle and it really seemed to be coming from under the the passenger side valve cover right at front, ether that or it is coming from under the intake manifold, right under the carburetor. I did a compression test on the engine and every cylinder is at 150 psi engine fully warmed up and carburetor wide open while cranking. And I am 4000 feet above sea level.
I have not over reved the engine ever since I got it and I have a rev limiter set to 6500 rpm.
What are some possibilitys here? Rockers? Valves? This engine was bought brand new in 2002 it's a 300hp crate 360 magnum and its got about 20 to 25 thousand miles on it.
 
I forgot to add that I only hear thiswhile the engine is at an idle, I can climb under the hood and give it some throttle and I don't hear it until I let it go back to idling.
 
thinking a lifter is bleeding out or maybe a stud pulling out? i dont know if they are screw in or not, just got my first small block a week ago lol...
 
If it's hydraulic, you might find that you could adjust the lash on that one valve a little and cure it.
Done that more times than I could count.
 
TrailBeast said:
If it's hydraulic, you might find that you could adjust the lash on that one valve a little and cure it.
Done that more times than I could count.
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they adjustable on a mag other than new rockers or new rods?
 
Negative,805. Bolt down/pedestal. Same mill,as your new rig.Can specs,even more mellow.
 
Abodybomber said:
Negative,805. Bolt down/pedestal. Same mill,as your new rig.Can specs,even more mellow.
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your gonna laugh but ive never had anything other than shafts! so is the adjuster on the pushrod or ?? lol

:newb: <i thought i was past this
 
No ,not adjustable. Torque to 25 ft.-lbs.,it's done. Just dealing,with the same mess,as I speak.
 
Well I just recently pulled my carburetor off to send it off to get some bushings installed on the throttle shafts because it was causing a pretty big vaccum leak. I do have an old edelbrock with worn out throttle shaft bores on the shelf that I could bolt on just to get it fired up and record it idling with my camera . I just don't know if you guys would be able to hear it on a video but it's possible, It kinda sounds like a tapping noise, kinda has the same sound as if you took a screwdriver and used the plastic end and tapped on the valve cover but its not extremely loud, and it seems to go away once you give the engine some throttle.
And I was under the impression that nothing under the valve cover are adjustable, but I have read that the mopar rockers suck, I don't know what this is but it kinda has me concerned. I haven't noticed any difference in performance from the engine, it still runs strong still has good oil pressure and the compression is still real good.
 
I'm hoping its a rocker or valve or something on the heads wich I am about 80 percent sure it is because I can deffanatly hear it on the top of the engine. I have been thinking about getting some new heads anyways but didn't plan on having to do real soon. Thinking maybe I could pop the valve covers off and make sure ll the bolts are torqued to 25 ft lbs, that's the only thing I can think of doing. Maybe try running some kind of cleaner thru the oil system, like marvel mystery oil or something?
This engine has had synthetic oil ran thru it all its life since break inn and the oil has been changed every 5 to 7 thousand miles with a wix filter and Valvoline synpower 10w-30 oil all its life, so its been taken care of, never has been neglected, but it has been ran pretty hard a few times but nothing extremely wild because its always been in a 4x4 truck.
 
And yes it has hydraulic camshaft, how would I adjust the lash on them? I have never done this before, but I am 90 percent sure the noise is coming from the passenger side valve cover area
 
Should be a be hydraulic roller..Normally, cams don't go flat here.Food,for thought.
 
So what else could it be? yes it is a hydraulic roller cam. Where should I start with trying to find this issue?
 
I threw my vaccum gauge on the engine yesterday and it makes 18 hg of vaccum at idle and the vaccum is rock solid steady. I have read if a valve is messed up that the vaccum will fluctuate at idle.
Vaccum is steady at idle. So should I start by taing the valve covers off and making sure all the rocker bolts are torqued to 25 ft lbs, is there a way to adjust the lash on these?
 
so everyone is out of idea's for where I should start to track this noise down?
 
Chances are it's a lifter getting tired. Not a big deal but 25K of hard miles will wear them faster. You can try a longer pushrod to get more preload but IMo it's more like you need to replace the bad one(s). Which is hard because you don't know which ones are bad on that side. If you're thinking of upgrading it might be a good time. Otherwise it's not fatal.
 
Also check the rocker arms for any signs of cracking or wear where push rods reside.
 
So getting some new heads might not be a bad idea? What would be more cost affective new heads or new rockers and push rods and lifterson the stock heads? I Have one more thing to rule out but cant until I get my carburetor back and that's the pcv valve, I have red they can be noisy sometimes too.
But if its not the pcv valve then I guess I will start looking into some new heads. What all will I need if o decide to get new heads? Should I get new rocker arms and push rods and lifters and springs for the new heads or just put all my old valve train on the new heads?
 
Or do new lifters normally come with new heads? Im just wondering what all I would have to buy for a new head install if I wanted to go all new and not use anything from my previous heads.
 
Hard to diagnose from a CPU,but first thing I must say is DO NOT rev that thing over 5500 rpm with stock valve springs!!! 2- there is NEVER valve lash with any hyd cam! Preload is what you want and with all stock parts should not be an issue,but it's easy to check. The factory cams can degrade and depending on how bad can have wear on the base circle(but pretty rare,unless you've been running that thing to 6500rpm for a while,LOL)that MAY be an issue,but I'd doubt that. What oil weight are you using? Have you recently changed to a heavier oil?
 
pjc360 said:
So getting some new heads might not be a bad idea? What would be more cost affective new heads or new rockers and push rods and lifterson the stock heads? I Have one more thing to rule out but cant until I get my carburetor back and that's the pcv valve, I have red they can be noisy sometimes too.
But if its not the pcv valve then I guess I will start looking into some new heads. What all will I need if o decide to get new heads? Should I get new rocker arms and push rods and lifters and springs for the new heads or just put all my old valve train on the new heads?
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God no. Figure the problem out first.
 
I dont think you need new heads.
Did the noise start all at once or did it progressivly become noticable?
If it started all at once something has came loose, progressivly worse than there is something wearing out.
 
I don't think you need new heads, pull the valve cover on the side that's noisey and find the loose rocker arm. Check to see if the bolt that holds it to the head is loose. The best thing to do is get very familiar with the magnum valve train. The lifters are below the intake manifold, they ride on the camshaft. I think Moper is right on this. Replacing the lifters can be done with the motor in the car.
 
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