[phk1967]

I started to hear a ticking sound over the winter and motor didn't seem to be running very well so I removed the valve covers and both rockers on the #3 cylinder were really loose, 1 push rod end was chewed up and the other push rod is stuck in the lifter.Any ideas on what could of caused this,was it the stuck lifter or something else? It has 7/16 screw in studs with roller rockers and the cam and lifters (both Crower)have less than 500 miles on them.I change the oil regularly and always use zddp or VR One racing oil.Before this the car was running great and didn't have any issues.
Thanks!

[phk1967]

So I took off the intake and the push rod on the exhaust valve was bent and the other pushrod was chewed up on the rocker end,lifters and cam lobes seem fine,so it must of been a sticking valve.What would be the easiest way to fix this without removing the heads,is there a way to check it?

[dmac]

I am no expert but since no one else has replied-

I would reinstall new lifter and pushrod and rotate engine by hand to verify valve action.

Also, maybe first, I would verify that all valves are the same height when rockers are removed. Any possible over-revving? Visually check springs. Maybe there is some way to check spring pressure when installed?

You could also do a compression test on that cylinder. remove all plugs and coil wire or use a remote switch to crank engine while testing. With a bent pushrod, my guess is removing the head is likely going to happen.

Plus you need to think about where the ground up end of the pushrod ended up if it more than just scratched up.

Good luck.

[PontGuy]

Since you say that there are problems with both intake and exhaust I think that it is unlikely to be due to sticking valve(s) or bad lifters, though possible. I would start by double-checking to make sure clearances are all adequate at full lift- especially retainer to valve guide clearance. If clearance is too tight and it binds up then something has to give. My experience is that stamped rockers are usually the weak link, but since you installed roller rockers next on the list would be the lifters and pushrods.

What engine and heads? Is this on an all-new build, or did you install a new cam/lifters in a running engine? What cam did you go with and did you install matching springs and confirm installed height?

[67cruiser]

What rocker ratio are you using 1.50?? or 1.65,s

[phk1967]

It was totally redone 6 yrs ago,blocks heads etc. just put in new Crower 60242,lifters & springs less than 2 years ago, it's running 1.52 rollers and it ran really well not ever abused or over revved.I had blocked the heat risers for a short period but car didn't like it so I pulled the manifold a changed back to regular gasket,I had a lot of black soot in the heads from the blocked risers.After changing out the intake gasket again is when the ticking noise started.When I pulled the valve covers I noticed the loose rockers and chewed end of 1 pushrod,the other push rod was bent down low which is why it wouldnt pull out from the top.Luckily it seems all the metal shavings were jammed in the push rod hole and didnt find any at all in the motor or heads.Valve spring heigt was good when they were installed,I dont see any damage to cam lobes and my heads all have a good amount of oil everywhere if that matters.I need to know what I should check before replacing parts to make sure it won't happen again,maybe next time I won't be so lucky.
Thanks!

[dmac]

The fact that both pushrods on the same valve are damaged makes me think that they were maybe adjusted just a little loose and gradually started wearing down, or too tight and were bottoming out in the lifter after the motor warmed up. I suggested checking compression to see if the valves got bent and are hanging open. Piston hitting valve will bend a pushrod. If valves were adjusted a little tight when engine was not fully warmed up, it wouldn't take much expansion to bottom them out.

[phk1967]

I just put a pushrod and rocker on that side and turned the motor by hand,lifters and valves seem fine.The rockers must of just loosened up somehow,I'm definately going to get a set of different poly locks.
I could use some input since I neeed pushrods should I use stock set or a good set of aftermarket ones?
Thanks again for everyone's help!

[PontGuy]

The only times I ever damaged pushrods or other valvetrain components was because of inadequate clearances somewhere. And that includes dirt-track racing Pontiac engines with some crazy combinations of "stock" components matched with high-lift cams running under brutal operating conditions. I guess that if valves are adjusted too tight or loosen up it could possibly cause damage though I've never had that happen to me.

You really can't be sure that everything is OK by turning the engine over by hand with hydraulic lifters. The lifters collapse under the spring pressure so you will not get "full lift" as you rotate the engine. When I am assembling I use a light test spring on a few of the valves just to be sure. That said, I would not expect any clearance problems with the 60242 cam and 1.52 rockers except maybe on a 326/350 and that depends on the heads used.

Hoping that one of the engine build experts chimes in. I've built a bunch over the years, but just for my own use so I can hardly say that I've "seen it all."

As far as what replacement pushrods to use- in the old days with that cam I would just buy good stock replacements and not think twice about it. But we are all a lot more conservative these days and a lot of the replacement parts aren't as good as they used to be. I would probably go with something that I at least recognized the name- Melling or something like that.

[lust4speed]

I'm not that surprised with the chewed out ends of the stock pushrods if they were re-installed. The stock ends really don't have a lot of meat, and when the switch is made from the original rockers to aftermarket, the wear patterns don't match up. I would bet you that if you pull the remainder of the pushrods, you will see some flaking around the center hole on all of them. The pushrod stuck in the lifter sounds interesting, any pictures?

Now the bent pushrod is another problem, and can't be explained away so easily. The simplest explanation is still coil bind, although I agree that the lift on the 60242 shouldn't have presented a problem.

Here's pics of a pushrod end starting to come apart, and one that has totally come apart:

[rexs73gto]

Jut a couple of quick questions. Did you reuse the same rocker nuts that were on the heads, the heads your using. If you did reuse the stock rocker nuts that was the start of your problem, & your lucky that the valves didn't loosen up sooner. Stock rpcker nuts are mainly a time use nut. They are designed to be a (crush) nut & are made to be put on once at the 23 lbs torque & left alone. If you want to reuse Pontiac rockers you have to buy a new set. There not chevy nuts. Did you resue the nuts.? Also what is the lift of the cam. Probely not a problem becaus you said you didn't hrear it right away. So if you did get rid of them right away & get some ploy-loc's & make sure you don't huet it again , ause it will sneak in the window at & give you bad dreams.

[PontGuy]

Good point on the roller rockers- could account for the chewed up end. I always use stock rockers in my engines, except for a couple of radical builds that got new aftermarket pushrods too. So a new set of aftermarket pushrods would be a good idea.

But in my mind the bent pushrod and the one stuck in the lifter are still the big questions. The only way I can see loose rockers causing this is if they got extremely loose, and cocked sideways enough to catch the rod end on the side of the pushrod recess in the rocker.

Also I just assumed that you are using polylocks with the setscrews on top to lock them in place. If so were the nuts still locked? And if not, I definitely recommend them for a build with an aftermarket cam, stock length pushrods and roller rockers. I would not rely on crimped Chevy style nuts, and definitely not the original Pontiac nuts which must be torqued down against the stud seat to hold.

[2002Z4CSS]

Originally Posted by rexs73gto

Jut a couple of quick questions. Did you reuse the same rocker nuts that were on the heads, the heads your using. If you did reuse the stock rocker nuts that was the start of your problem, & your lucky that the valves didn't loosen up sooner. Stock rpcker nuts are mainly a time use nut. They are designed to be a (crush) nut & are made to be put on once at the 23 lbs torque & left alone. If you want to reuse Pontiac rockers you have to buy a new set. There not chevy nuts. Did you resue the nuts.? Also what is the lift of the cam. Probely not a problem becaus you said you didn't hrear it right away. So if you did get rid of them right away & get some ploy-loc's & make sure you don't huet it again , ause it will sneak in the window at & give you bad dreams.

I had a problem with the valves being too tight on my 400 after installing a Melling cam and lifters and using the stock Pontiac rocker arm nuts torqued to specs. The base circle of the cam was bigger and causing the valves to be very tight and hang open slightly. To fit this concern I was going to buy some poly locks but just brought some brand new Chevy rocker arm nuts and adjusted the valves like a Chevy and no more issues.

[72LuxuryLeMansLa.]

Originally Posted by lust4speed

I'm not that surprised with the chewed out ends of the stock pushrods if they were re-installed. The stock ends really don't have a lot of meat, and when the switch is made from the original rockers to aftermarket, the wear patterns don't match up. I would bet you that if you pull the remainder of the pushrods, you will see some flaking around the center hole on all of them. The pushrod stuck in the lifter sounds interesting, any pictures?

Now the bent pushrod is another problem, and can't be explained away so easily. The simplest explanation is still coil bind, although I agree that the lift on the 60242 shouldn't have presented a problem.

Here's pics of a pushrod end starting to come apart, and one that has totally come apart:

Hey Mick, you could sell that one as a "Custom Chrome" drinking straw on ebay

Karl

[rexs73gto]

Changing from stock to roller rockers shouldn't have given you any problem. But again if you REUSED the rocker nuts you can almost say for sure that the reason the push rods bent is because the nuts came loose & allowed them to bounce around in the slot. Then when it was going up or down it was not in the proper place causing the push rod to get squished in the valley bending the push rod. That to is what happens when the timing chain breaks to. Get some new push rods, all new & then use the poly-locs to adjust them to zero lash plus 1/2 turn & you will be ok. Don't forget to replace the lifters to as those will be damaged to.

[phk1967]

At first I assumed it was stuck in the lifter cause it wouldnt pull out from the top,after I pulled the manifold it was clearly bent.My valvetrain is adjustable and converted to 7/16,was using the nuts and poly locks that came with the rollers not the stock ones.The ends of the other pushrods all look fine. I really think the poly locks weren't snugged enough and both loosened on that cylinder.Guess I'll know for sure this weekend after I get the parts and install them.

[rexs73gto]

Heres food for thought, I like to install & adjust my rockers with the valley pan off so I can look at each lifter as it rolls on the base circle of the cam. That way I can see it & know it's on the base of the cam when I adjust the rocker arms. I do them one at a time starting with either number 1 or 2 cylinder & roll it around to each base of each cam lobe, that way I can see it on the base & know for sure each one is done correct. It takes a little longer to do it that way but this way I know it's done right. Then when you start it up they are all right where they should be so when everything is put back on all you need to do is start it up & either break it in or go out & drive it.