Technical Update: Does this look bent?

Why would you need taller studs for poly locks or stud girdles? Poly locks replace normal nuts, so nothing longer needed to use them. And stud girdles clamp to the poly locks, so nothing longer needed there either?
Those studs look like the nuts are cranked way too far down to me also. And added washer is even more suspicious with all the stud exposed.

 

I am beginning to wonder if the OP is aware of the procedure needed to adjust Chevy valves. I read somewhere on this site (recently) that Pontiac rockers get tightened down/there is no adjustment (I have no experience with Pontiac) so maybe that is what is happening here.

 

Makes you wonder where the nut on the new rocker ended up, doesn't it?
Still, ZZ says it ran good for 4 years.. Good is a relative term, I realize.

 

Fully aware

 

Good to know, thanks for not taking that comment the wrong way

I think I'd be measuring the length of a pushrod to verify it/they are stock length. If the pushrods are stock length, then the only thing I can come up with regarding 'running out of thread' is the stud boss not being milled enough, shorter than stock lifters were used (really grasping here ) or a reduced base circle cam.

 

Didn't break the rocker ball, broke the added washers above it.

 

Looks like it wasn't machined for the screw in studs AND guide plates. The washers were needed to allow for the thickness of the guide plates.

Gary

 

Push road guide hole... Now you see it . Now you don't. Camera angle?
First pic looks like the standard slotted guide hole..PR over to the left.
Second, it looks like the holes have been drilled out, but PR is still to the left of the hole but still in the guide plate?
The pad for the guide plate seems to be machined in these pics....Some, anyway

 

I've come across washers on top of the balls to 'take up' worn components.
Looking at the pushrod end, that hole looks a little munched, how badly worn is the tip and/or the rocker?
If the rocker/pushrods are worn someone may have put a washer on the ball to get rid of the tick.

 

Could be something simple like someone put in long screw in studs and ran out of threads before proper adjustment could be made.
To compensate they put washer between the rocker ball and adjustment nut. Believe it or not I’ve seen this before not proper for sure but with a good quality hardened washer it probably would of lasted. Now the problem with the rocker contact on the edge of the valve stem that a whole other issue.

 

It probably had a set of thicker roller rockers at one time that the previous owner removed before he sold it.

 

Thanks, fixed it

 

Here's what I am thinking now ... if it ran fine for 3-4 years then just get yourself a new washer and hit the road

I'd set the rockers with the absolute minimum preload to keep the rockers as high as possible and go ...

 

It needed a new rocker, it appeared., and to be set properly. He's already done this. We are now waiting for the results.
It's all here in the three pages

 

Sorry, yeah I got that ... initially I was figuring it would be wise to find out why the rocker balls needed washers (push rods too short due to incorrect part or wear/damage, small base circle cam, heads machined incorrectly not taking into account the guide plates, wrong screw in studs etc) but now my thought is to just get it back up and running since it apparently ran well enough for four years.

 

Yeah..That's why I wanted to see a pic of the underside of the rocker...We haven't.
Also wanted to see where the nut ended up, after being set properly without a washer..We haven't.
We know he couldn't have used the clickety- clack method, because it doesn't run, at the moment.
Once again, threads like this take a lot of guesswork and crystal ball gazing

 

"You can get any color spark plug wires you want, as long as they're yellow"-Every Box Parts Store. Pet Peeve of mine, won't do it. Ordering a set today. I'll keep u guys in the loop.

 

My opinion also. Looks like the rocker isn't centered on the valve stem. Pushrods might be to short, causing the whole issue.

 

Like a collapsed lifter due to wear and formed a hole at the bottom of the lifter. Seen what I just mentioned and the washer trick (stacked in this case) done years ago. Late 70's. It was on a Pontiac 400. Who suggested this, none other than Fritz Voigt. Fritz told Gary Wise the owner of the Pontiac that it was something they did to stay in the race only.

 

I don't know how the p.r. length could cause this. I just assumed it's because you've got a broken washer jammed in under the nut, pushing the rocker to one side.

 

Pushrods too short would help explain running out of threads on the stud (assuming everything else is correct). Measure the pushrods and if they measure fine, move the search elsewhere.

The broken washer is (or certainly appears to be) the problem ... the question is why are they running washers in the first place. Pushrods too short is a possible reason the washers are needed.

 

How long are the pushrods?

 

I assumed that Lloyd was saying that the pushrods, in themselves, being short, would cause the rocker to go off center. Still don't see that.

 

Good luck on this...Already back together.
Still trying to find out how the nut looked when set correctly, minus the washer.

 

https://www.eatonbalancing.com/wp-content/uploads/2007/12/YBM-70-Rocker-Arm-Geometry-full-page.jpg

Short pushrods would be the bottom diagram.

 

Yes, but even if this was the case , it's been running for 4 years like this, until one of the washers broke.
We ARE talking about side to side off center, as in post #1 , right, guys?

 

After giving this a lot of thought ... I have decided I can't decide which is still a decision

 

I wanna know what happened after he fixed it.

 

Well, it ain't gonna fix itself!

 

I'm talking about this. The pushrod length determines where the rocker contacts the valve stem, and also with a short pushrod, you're gonna have to tighten the nut to the bottom to create a fulcrum. And when you run out of threads, you have to start placing spacers in there. What I'm saying, is that the rocker geometry looks off to me, but I'm sure that I'm wrong. Hey it lasted 4 years, put it back together and hope for 4 more.