Opened 'er up and this is what I found

[DoubleDingo]

You were right @HotRodPC, it was evident what was causing the noise. I suspect I'll need to take off the intake too. But before I tear into it any deeper, what do you all think may have caused the rocker to rotate like that? Is that from a bent push rod? @BADAZ chevy guy @RetroC10Sport @raylanr

A recap, was driving down the freeway, truck ran great, no overheating, no missing, no backfire, just an odd noise, not a loud noise, but enough noise to be audible, and then it lost power and had a definite ticking sound on driver's side bank of the engine that can be heard with hood open. Starts right up, idles smoothly, has about 40 psi oil pressure, just no power

 

[Driver4r]

And since it was exhaust, It would have been harder to make power cause that cylinder was trying to fill with A/F while it was still full of fumes. If it had been intake, it still would have made power easier.

 

[mtnmankev]

If the rocker nut was tightened properly and no bent pushrod, I would place the blame on the same space aliens that have come here from their home planet to mess with me.
I have never seen one do that on its own.

 

[HotRodPC]

By the looks of the threads left on the stud, the nut didn't back off. So BEFORE you pull the intake, do a little investigating. You might not need to remove the intake to make the repair.

So somehow the rocker got loose enough, or damaged enough to slip off the valve. Several things can cause this. Bent push rod, pressed in rocker stud being pulled out of the head, rocker arm wear or break at either the valve tip or the push rod socket. All of those items can be checked and repaired without pulling the intake and head. Even a rocker stud pulling out, you can drill it, tap it and put in a screw in stud to fix that. If the push rod bent bad enough, need to figure out what caused or if it was just a defective push rod.

Other things that can be wrong, valve tip is wore and/or angled off to where the rocker arm slips off the valve tip. Lifter completely collapsed or will not fill with oil (hydro lifter) and the pushrod is damn near at the floor of the lifter and not getting any lift. Cam lobe is wiped out.

You can even check some things without pulling the intake, like if the cam lobe is wiped out. Get a straight pushrod, set the rocker where it goes, and crank the motor over watching the valvetrain operation. That may give a clue what's wrong. Then pay close attention to the travel on the rocker via cam lobe and how it visually compares to the rest of the rockers. If it looks real similar chances are the lobe is OK, but to know for sure, it's best to measure the lift with a dial indicator and compare to a couple other of the same valves, ie intake or exhaust. Don't compare an exhaust valve to an intake valve, the lifts can be different intentionally during cam manufacturing. If you're not getting much lift, at that point, you know it's going to be either lifter or cam lobe, so go for it, NOW you can pull the intake.

 

[Swims350]

I've never seen retainers like those has somebody changed them out? All I've seen have came down over the top like cups, and those are just flat like washers on top of the springs.

 

[DoubleDingo]

@Driver4r That makes sense with that cylinder unable to expel the spent gasses.

@HotRodPC Thanks, that helps a bunch. I don't have a dial gauge though. It all looked okay except for that rotated rocker. There are a couple other rockers that aren't sitting center on the valves. I wonder if I need better rockers. I read something about self centering rockers, but to me, stock rockers self center by design. I definitely don't want this happening over and over.

@Swims350 Those are bone stock vortec heads from GM Performance, removed from the box, packing material unwrapped, and heads installed. They have roughly 1,000 miles on them.

 

[DoubleDingo]

I have this cam/lifter kit sitting here, I am extremely tempted to swap it in while the truck is down. What do you guys think, will it work with my setup? I think the gears may need to be changed to get the cruise rpm within spec, but this cam seems like it will generate some decent pulling power with the vortec heads.

 

[Swims350]

oh vortec that's why I was thinking old school and tbi setup. did the rockers come with the heads? I thought I had saw something about self aligning rockers? not sure. From what I had gathered vortec required or came with self aligning ones and others did not?

 

[350runner]

Heck ya put that kit in! What's the lift#on the [email protected]

 

[HotRodPC]

Dial indicator at HF.

Cheap but effective. Now if I were making rifle or handgun parts, NO I wouldn't use this. For stock motors, stock transmissions, it's fine. I use this one for checking end shaft play on input and output shafts on trans builds.
$14.99 http://www.harborfreight.com/1-inch-travel-machinists-dial-indicator-623.html

$14.99 Magentic Base, http://www.harborfreight.com/multipositional-magnetic-base-with-fine-adjustment-5645.html

Of this rootin' tootin' handy doodad for $32.99 and you get a way to clamp it and the dial indicator all in one package. http://www.harborfreight.com/clamping-dial-indicator-93051.html

I have a 25% off one item coupon at HF for July 4th Only. That brings the cost of the dial indicator and vise clamp with flex shaft to $24.74. Everyone here should have one of these tools at the price of $25. I'd also trust it for setting up ring and pinions. The thing about this tool is, the fact you can zero it out by turning the outer ring. So you're actually measuring the distance traveled and not depending an accurate measurement like the length of something. If you don't have an HF local, I'm pretty sure the coupon works online too and have it shipped.

Coupon Link http://widgets.harborfreight.com/ws...2714b&utm_source=1021&cid=mEmail_s1021_c2714b

You must be registered for see images

 

[DoubleDingo]

The more I read about it, the more I realize this is a blessing in disguise. I need to get some self aligning rockers, and while I'm at it, some new pushrods.

 

[DoubleDingo]

Dial indicator at HF.

Cheap but effective. Now if I were making rifle or handgun parts, NO I wouldn't use this. For stock motors, stock transmissions, it's fine. I use this one for checking end shaft play on input and output shafts on trans builds.
$14.99 http://www.harborfreight.com/1-inch-travel-machinists-dial-indicator-623.html

$14.99 Magentic Base, http://www.harborfreight.com/multipositional-magnetic-base-with-fine-adjustment-5645.html

Of this rootin' tootin' handy doodad for $32.99 and you get a way to clamp it and the dial indicator all in one package. http://www.harborfreight.com/clamping-dial-indicator-93051.html

I have a 25% off one item coupon at HF for July 4th Only. That brings the cost of the dial indicator and vise clamp with flex shaft to $24.74. Everyone here should have one of these tools at the price of $25. I'd also trust it for setting up ring and pinions. The thing about this tool is, the fact you can zero it out by turning the outer ring. So you're actually measuring the distance traveled and not depending an accurate measurement like the length of something. If you don't have an HF local, I'm pretty sure the coupon works online too and have it shipped.

Coupon Link http://widgets.harborfreight.com/ws...2714b&utm_source=1021&cid=mEmail_s1021_c2714b

You must be registered for see images

I will get those so I can do this better this time around.

 

[HotRodPC]

All you need is the $15 dial indicator and the $15 mag base, OR just the $33 dial and flex shaft clamp. In most cases, the flex shaft clamp works better for automobiles. Like doing transmissions, I can clamp onto the bellhousing. Magnetic base doesn't stick to aluminum. So I mag base it to my metal trans pan table. The trans is heavy enough it doesn't move. In your case, you can clamp to the head lip where the valve cover bolts on. On an axle you can usually clamp the axle housing. Which ever you decide, you can also get the $25% on one of the 2 of the indicator or mag base, or you can get the 25% off on the whole kit of the $33 kit. The 25% off and able to use it on the whole kit, makes the flexshaft clamp and idicator kit the better deal.

Just go to the coupon link and print it off and take it with you, or just get the code off of it to order online.

 

[DoubleDingo]

Heck ya put that kit in! What's the lift#on the [email protected]

The specs I posted say 0.05 but then say 0.39 and 0.41. I am dumb when it comes to cam specs and lifters and pushrods, to achieve the right valve lift at the head.

I looked at the paperwork in the box, it says:
Intake@cam 2597 @VALve 390
Exhaust@cam 2735 @VALve 410
Rocker Arm Ratio 1.5
Cam Timing @0.05 Tappet Lift Intake opens 10.5* ATDC closes 25.5* ABDC max lift 108* ATDC 195*
Exhaust opens 37.0* BBDC closes 15.0* BTDC max lift 116* BTDC 202*

It was ground by Crane Cams.

Somehow it tagged VAL when I mentioned the intake and exhaust @Cam, go figure...lol...I edited it out

 

[DoubleDingo]

oh vortec that's why I was thinking old school and tbi setup. did the rockers come with the heads? I thought I had saw something about self aligning rockers? not sure. From what I had gathered vortec required or came with self aligning ones and others did not?

No I used the rockers off the 81 engine because the heads didn't come with any. I did make sure to match each rocker with corresponding pushrod and lifter and how the pushrod came out, so the wear patterns were the same. I am just realizing the more research I do, I need to buy some parts before I commence fixing this.