Valve Clatter; No Rocker To Pushrod Contact

[master_bayshin]

Update: broken pedestal was not the problem. There is still tons of play in the rocker on number 4 cylinder even with an intact pedestal. I don't even know if that was the rocker that the broken pedestal came off of. So say it's not a collapsed lifter, what could it possibly be?

 

[Dave2000GT]

Update: broken pedestal was not the problem. There is still tons of play in the rocker on number 4 cylinder even with an intact pedestal. I don't even know if that was the rocker that the broken pedestal came off of. So say it's not a collapsed lifter, what could it possibly be?

I dont quite get how you didnt notice which rocker the broken pedestal was from?
Regardless, chances are that it is from cyl 4 if the geometry is messed up on it. Not really sure... So compared to other pushrods at base circle that one sits lower ? If so then yah i guess something is up with the lifter. Probably want to take a look at them if thats the case.

 

[master_bayshin]

I literally pulled all the rockers off, pedestals, bolts, plates and all and set them down trying to keep them together. Later on I noticed a few broken pieces of pedestal in my pile of rockers.
So I assumed it was from cylinder 4, and I put a good one back on. Noticed that cylinder 4 exhaust rocker still has up/down play at base circle, whereas none of the other rockers do.
Today I will set it back to TDC compression stroke, and pull the lower intake

 

[Dave2000GT]

Crazy - wonder how the lifter broke if that's the case ? Maybe you didn't have any preload on the lifter - I've read that without preload you can cause the lifter snap ring to pop out.

 

[master_bayshin]

Possible, but curious because I have a fully nonadjustable valvetrain. I brought it to zero lash then counted the turns it took to reach 20 ft lbs of torque on the rockers, and I got 3 turns. That suggests the opposite; too much preload. However when I checked wear patterns on the valve stems, they all looked to be centered, suggesting my pushrods are in fact the correct lemgth

 

[Dave2000GT]

Possible, but curious because I have a fully nonadjustable valvetrain. I brought it to zero lash then counted the turns it took to reach 20 ft lbs of torque on the rockers, and I got 3 turns. That suggests the opposite; too much preload. However when I checked wear patterns on the valve stems, they all looked to be centered, suggesting my pushrods are in fact the correct lemgth

Dayum! 3 turns is a ton, you might have been close to bottoming out the lifter. Factory spec is 3/4-1 turn and that is supposed to put you at the 'midway' point in lifter travel. I recommend no more than 1/4 for best performance personally. Add in some thermal expansion - after a few minutes of driving - and you well could have bottomed out that lifter! Really badly. I'm not really sure how exactly that would have caused your issue, but it can't be good. At the very least you'd be getting major valve float and loss of power, increased noise. Get the preload set right next time !

 

[master_bayshin]

How exactly do I do that when I'm supposed to torque the rockers down to 24 ft lbs?

 

[Dave2000GT]

How exactly do I do that when I'm supposed to torque the rockers down to 24 ft lbs?

Shims under the rocker pedestals.

 

[master_bayshin]

Which effectively shortens the pushrod correct? I have ordered new pushrods and a shim kit, but the pushrods I ordered are 6.300 instead of the 6.270s, so I may have to order another shim kit..

 

[Dave2000GT]

Yup- but if youre getting 3 turns if preload, it means the pushrods are too long (but not my much) so the shims are needed.

 

[master_bayshin]

Got it. The help is much appreciated!

 

[master_bayshin]

This is the suspect lifter. What is going on here?

 

[master_bayshin]

Also broke a dogbone. I'm guessing I've wiped a cam lobe too. Awesome.

 

[master_bayshin]

So the entire roller came off the lifter. And the other piece of the dogbone is nowhere to be found. Safe to say I need a new cam?

 

[jka]

If you do not find the broken parts inside the engine you will need another engine..not just a new cam.

 

[master_bayshin]

Chance they could be in the oil pan?

 

[addermk2]

You've got to tear down. The roller and pin could be lodged down between the crank and a main support.

I wouldn't even crank that engine... I'd be taking it out.

 

[Dave2000GT]

There's a good chance you could find it in the oil pan, but there's probably other damage already taken place in the motor... Damn that sucks!

Now what I would do (take it with a grain of salt), is get a good lifter, piece it back together and put on the rockers, and hand crank the motor to get an idea of where you might be at. Might give you an idea of whether you can clean things up externally before committing to a tear-down.

 

[liljoe07]

I'm sure the cam lobe us ruined too. Most times, all the aftermath you are seeing is from a locked up roller wheel. So I wouldn't be surprised to find a flat wheel in the pan.