I have adjusted the rockers on my 73 (now an 83 truck block) while running. After a few startup cycles, I had to go back and readjust the last rocker on the passenger side again since it started ticking again. We were thinking the stud may have been slipping out of the head so we hammered it back in and tried twisting it to get it to bite a little better.

When I put the rocker arm back on and started it up, it seemed like it was not moving as much as the other 7 on that side. I put the rocker back on the way I pulled it, but now I'm second guessing myself. I'm afraid I may have flipped the washer upside down causing the rocker to not move as much as the others. Would that be the case if I flipped the washer on the stud? I drove it and it seems to run great with no smoke or valve noise, but then I started thinking "what if I flipped it?". I felt all the exhaust rockers after I adjusted it and they all felt the same, I didn't adjust any of the others since I had already done them and they weren't making noise. What do you guys think? If I flipped the washer would it be running poorly, or could it be fine now but lead to damage later? Thanks.

 

Sounds like the cam lobe may be getting round instead of lumpy. Definitely check the rocker to see if the pivot washer/ball is on correctly, and check to verify the movement.

 

If you have any doubt about the position of the semi-spherical washer, you need to pull the valve cover and check. If it's wrong, takes things apart and get it right. Get the lobe on the base circle and re-adjust it.

You should mark around the base of the questionable stud with a scribe, so you can look at it again and see if the stud is actually pulling out. If you think there's a chance that the same lobe may be going flat, you need to inspect this part of the valve train periodically until you are sure that the valve adjustment is holding.

 

The rocker studs in a stock head are press fit, and it's not unusual at all for them to pull out. If you hammered and twisted one of the studs, that press fit is almost certainly destroyed and I have no doubt that it pulled immediately after that. In the future, if you suspect this is the case then put a non-precision straightedge across the flats of the studs.

In this case I expect you'd see quickly if the rocker ball was upside down or if the stud had pulled just by looking at the rocker nut adjustment on that stud as compared to the others.

A pulled stud is a relatively easy fix although kind of a PITA on the car - tap the boss for a shoulderless screw-in stud.

I'll avoid the touchy subject of adjusting the valves with the engine running as that seems to bring folks out of the woodwork - but there's no need to do it that way.

 

Thanks for all the fast responses. As certain as I am that I put it back the way it was, the shadow of doubt is festering in my brain and I'll have to pull the valve cover for my own piece of mind. I was simply wondering if by flipping the washer would the rocker appear to not move as much as the others, even with the adjusting nut quite loose? I didn't notice the engine hesitate when I adjusted that one, as I have before. I'm thinking the worn cam makes some sense despite this engine's fairly low mileage (20000?).

Let me just say I realize this is not proper procedure. Nevertheless, this car has 200k plus miles with multiple engine rebuilds and replacements since my father bought it in 77. Originally the car was an L48, now the block is a 4bolt LT9. This car has been pieced together over the past 35 years and had been sitting outside in the desert from 2007-2012 until my dad agreed to pass it on. The motor was put in around 1991 and as far as he remembers, they put the stock heads back on and reused the stock studs. He had a problem with the same stud on the drivers side backing out about 10 years ago and mushroomed the tip trying to pound it back in. He was the one that recommended I try pounding it back in with a socket, which I did. This car has many other issues I have to deal with but it is truly a survivor, not a collector. I'm simply trying to get the engine to run somewhat reliably from what I've found online and talked with my dad about.

 

If the rocker pivot ball was upside down, there is no way it would even look like the others. I'm not 100% sure there would even be any protrusion of the stud above the nut. At any rate, I'd bet it would destroy that rocker in very short order.
Any noise from the valve train?

And I'm with Billla- just the mention of how to adjust valves starts a 3 week discussion. Everyone has their own tried-and-true method that works for them. As bad as the "what oil should I use" question does.

 

Okay that is exactly what I was wondering. When I put it back together it looked exactly like all the others from the top I was just worried I flipped the pivot ball on accident but I really don't think I did. The engine was perfectly quiet, no smoke, and seemed to be running quite well. I'm still tempted to take the valve cover off again and take a look just for peace of mind. I'm still wondering rocker did not appear to be moving as much as the others at the time.


As far as the valve adjustment debate I totally understand and did not intend to open that can of worms.

 

IF it's running fine, and no noise, I'd be tempted to drive it. IF it starts making noise (big IF) then pull the cover and take a close look. You could pull the cover and start it (yes, it's messy) and take a look and see if that rocker is moving as much as the others. If not, check the pushrod to see if it's straight. You did look at the rocker arm when it was opened to see if it was discolored (blue) from heat? Sign of a failing rocker.
Down side to just driving- if the cam is going away, the metal from that is going to end up everywhere in the engine.

 

[QUOTE=billla;1585394906]The rocker studs in a stock head are press fit, and it's not unusual at all for them to pull out. If you hammered and twisted one of the studs, that press fit is almost certainly destroyed and I have no doubt that it pulled immediately after that. In the future, if you suspect this is the case then put a non-precision straightedge across the flats of the studs.

In this case I expect you'd see quickly if the rocker ball was upside down or if the stud had pulled just by looking at the rocker nut adjustment on that stud as compared to the others.

A pulled stud is a relatively easy fix although kind of a PITA on the car - tap the boss for a shoulderless screw-in stud.



I doubt the rocker ball is upside down. The amount of threaded stud above the ball would be different on the one in question. Pull the valve cover and place a straight edge acrodss the tips of the studs. See if any or how many are raised.
Like Bills=a said, it's a pain to pull and thread the stud bosses while on the car. Can be done though.

 

Thanks Tim and Indian. I had the valve cover off before with the little oil clamps on the pushrods and it seemed like that rocker was not moving as much as the others. The threads above the rocker are definitely close measurement wise. I didn't pull it today but I pulled the breather hose off and looked/felt inside and it still didn't seem to rock as much as the intake rocker next to it.

As far as the blue, it seemed like there was a blue tint on the stud but not the arm. I'll still pull the cover and recheck the pushrod. Still no noise and the engine runs fine. If it was running with that valve out of adjustment too long could that have caused premature cam wear on that exhaust valve?

 

This seems to pretty much answer the question - I would certainly replace this stud. The tool below, plus two studs and about an hour's work is all it takes.

http://www.summitracing.com/parts/cca-5306/overview/

If a stud is loose, the *only* real fix is to replace it with a screw-in stud.

 

If they start coming out they will continue. Often once one begins to back out shortly others will follow suit. You could pin them, but threaded studs are easier and stronger. If you thread them, mask off the stud bosses like you were going to paint them. Spread some grease or vasoline on the mask around the stud bosses.
The last thing you want to do is go through all this work and send debris past the bearings.
Another test I'd do would be to remove the rocker and with finger pressure on the push rod, have someone turn the engine over by the crank bolt and see what the lobe lift really is. Makining sure you aren't having a lifter/ push rod issue causing the lack of rocker movement.

 

Thanks Indian, I'm guessing I would need to use a ruler to measure the lift right? Is it possible to measure a cam's rough specs while it is installed through this method? My dad seems to think it may have an rv or Baja cam in it. Either way, I think it makes sense to measure this cylinder and another for comparison.

As far as the studs, I was hoping to get it to simply continue to run reliably for the time being. I won't be taking it on any road trips any time soon. The plan is fix the power steering control valve, fix the transmission leaks, fix the automatic tranny lockout cable, fix the guages that aren't working and do a little interior preservation first. Then, get a Summit set of inexpensive roller rockers and screw in studs, provided the engine in good shape. Of course if its not, then who knows.

 

I would fix the studs first - the rest of those issues are cosmetic; if the stud comes all the way out, you could easily make scrap.


Measuring lobe lift in-car is tough to do - the pushrod isn't held square in all respects with the centerline and it moves during travel...so even with a dial indicator it's iffy...but it might give some indication at least. Better to get a dial indicator against the rocker as well as you can I think than trying to take it off the pushrod.

 

Do the easy most logically thing first. If a pressed in stud becomes loose you need to replace it with a screw in stud. I have seen many other types of Bubba fixes, none work.

 

Hey billla, you're not on ignore, I apologize and no disrespect intended. I greatly appreciate and respect your responses. Of course, you're right. I'm trying to band aid many things every time I take her out of the garage. Your point is clear, an engine is more costly than a power steering pump. I was eventually intending to do screw in studs and rockers, I was just hoping to buy some time. I guess I'll have to replan my attack.