Drivers side valve cover sounded a little 'marble like' underneath while idling. Nothing too loud, but noticeable with a broom stick when comparing to the passenger side.

Thought it might be the PCV, so replaced and still hearing it. I pulled the valve cover to see if anything was out of order visually, but is not.

Without pulling the manifold, is there a way to measure whether the valve lash on each cylinder is correct? A couple of the rockers 'seem' to be slightly more loose than the others, but not exactly sure how different each one should be depending on rotation.

I've read about the procedure, and watched a few videos, but does anyone have any tips on getting this done? It would seem that this is the source of my noise. I believe I have hydraulic lifters vs. solid, as the block is from '87 or newer, but not completely sure as I cannot see them.

Thanks!

Chad I like to adjust engines with hydraulic valve lifters while the motor is running using a cut up old valve cover that allows me access to the adjusting nut. This way I know the plunger is where it should be and any wear has been accounted for (it is also a lot faster which when you are charging from a flat rate book puts money in your pocket).

This method doesn't center the rocker over the valve stem which you would do on a high dollar high performance engine build (but I wouldn't have to worry about hydraulic tappets either as I favor solid rollers for street and the race track). And why most don't use this method is that it gets oil spread every where; even with the valve cover catching most of the spray. It isn't so bad that a can of engine cleaner and a power wash won't make it look all new again, (or at least cleaner than most cars that customers drag in the shop).

Now I have to ask why you have a valve lash issue? Hydraulic lifters with stock pressure valve springs generally will stay set for the life of the car. I ask because if you have opened up enough of a lash to hear them clacking like an old sewing machine then there is evidence of wear.

This brings up the issue of flat tappets and modern engine oil which doesn't have the minerals blended into the oil in sufficient amount to protect the engine. Metal on metal wear was usually protected by Zinc and Phosphates that sacrificed themselves to lubricate the parts. Those metals were removed because they cost money, and some one thought that there was a chance that the metals could hurt the catalytic converter on your 1967-'69 Camaro. The fact that your car doesn't have a cat doesn't mean you get the metals you need in your off the shelf motor oil. You have to proactively go out and buy it and add it yourself at every oil change or buy ZDDP rich motor oil to begin with.

I would be concerned about a cam lobe going flat, and the metal that enters the motor oil because the worn lifter is shaving the cam down just like a lathe turns metal creating tiny shavings. Those shavings embed themselves in the bearings and wear away at the crank and cam creating even more metal loose in the motor. To detect this some have their oil filters cut open looking for metal, or drop the pan to see if there is any loose metal filings in the bottom of the pan.

Another way to check for a flat cam is to put a dial indicator on each rocker tip and compare the lift at the top of the push rod to see if all are the same. If not you have either a collapsed lifter or a worn cam. Either is cause for further investigation.

Larger Dave

Dave - Thanks for your detailed response. I don't know a lot about the motor, other than the year of the block and any other info that I've deciphered from casting numbers, which isn't much. I was told that the motor had been rebuilt about 2 years ago, and I've had it a little over a year. I have changed the oil a couple of times, and the first time noticed a few metal flecks in the pan, but not in the filter. Second time, a few less metal flecks in the pan, and none in the filter. According to the maintenance records, not a lot of mileage had been placed on the motor from the previous rebuild, so wasn't sure if I actually this was normal break in or if something was eating itself.

I had a friend tell me the exact same thing with respect to hydraulic lifters, in that they shouldn't need adjustment, and if they do, then it can indicate another issue. The passenger side of the car under the valve cover is very quiet, like a small sewing machine. As I mentioned, the other side was a little louder (like marbles), close to the PCV, and from videos I've watched, assumed that perhaps the lifters needed a little adjustment.

I'm planning on my first engine build at the first of the year, but wanted to be sure that I get as much as I can out of this motor, and thought that adjustment may be in order to assist with its longevity.

I don't have a dial indicator, but might be time to invest in one.

Agree with Dave on the old proven half valve cover splash shield.
I went with the rocker arm clip plugs. Works well, just get the job done before oil really heats up.

Other method I use on hydraulics is the finger no spin and adding 1/8-1/4 turn.

For solids I always set old school one up/ one down method with motor hot.

As for looking for lost rocker arm movement, the method Dave mentions works well. If you have the opportunity to watch the rockers movement while running, you may just spot the one with a bad lobe.

Push down on your push rod via rocker arm and if it moves then you have hydraulic lifters. If it doesn't budge then you have solids.

Providing he doesn't pick a hydraulic lifter that's collapsed or totally bled down . Move to next one. Surprised he could hear this with a broom stick? I go for my old school garden hose stethoscope.

I pushed down on the push rod by the rocker arm and can't get it to budge on any cylinder, so must be solid lifters. The broom sticks with metal ends are pretty sensitive to sound.

So Don brings up another question for me. If adjusting when cold, I've reviewed two methods of adjustment. One, you stop at TDC (Compression), adjust #1 inlet and exhaust, rotate 90 degrees, then follow the firing order for adjustment, with a 90 degree turn in-between each cylinder. Or two, rotate to TDC compression, then adjust all valves that correspond to that rotation, then turn to TDC Exhaust, and do the same until completed. Is there any way more 'correct' than the other, or are there multiple ways to skin a cat so to speak?

Sounds like you are talking solids, so for me I don't adjust both at the same time, you really have to watch to make sure both valve are closed and the lifter not on the heel or toe of a lobe, that's why I do the one up one down method. I use a remote to make sure the valve is fully closed and not near a lobe ramp.
I can get critical but after 40 years of bumping and rolling, I pretty much know where I am on the solids. I have a cly setting sequence listed on my tool box but haven't done that since I quit racing . You can do the 90° rotation method, just have the balancer marked.
Hydraulics, its the same for me but I fell the push rod or feel for the spin. When in doubt, I back off, look for the preload then 1/8-1/4 turn. There are other methods but this works for me on my retro rollers.

Thanks Don. Yes, I believe they are solid lifters, as I cannot get any play when I push down on the rod. Are the adjustment methods the same for both hydraulic and solid lifters? Does it make a difference?

I also reviewed a third method where zero play is measured using a .0015" feeler gauge (which I have), where adjustment is made for a tight fit of the gauge at the tappet, then followed up with a half turn, where the order of adjustment is the same.

You should be able to shine a flashlight down in one of the pushrod holes and see the lifter tops. This pic shows the difference although I don't know how accurate.




If they're solids, someone (it might've been Fred?) posted up a great way of setting solids.....since you typically want to set them hot just adjust one set, then let the engine cool. Go back then and check the new lash on two that were adjusted and set the rest cold to that measurement. I reckon if one side is good you could do the same....just check two or three on the good side and then check the ones on the bad side to see how they compare.

Some good reading:
https://www.centuryperformance.com/f...ing-Valve-Lash

Thanks Steiner. Just verified that they are indeed Hydraulic, and not solid. Begs the question why I can't push them down? Maybe they are loaded with oil which makes it difficult.

I set solids and hydraulic lifters per GM service manual procedure.

Solids


Hydraulic and roller lifters - 3/4 down from 0 lash.
TDC#1 set
EX - 1-3-4-8
IN - 1-2-5-7

Rotate to TDC #6
EX - 2-5-6-7
IN - 3-4-6-8

You can't push on the push rods and get give because the hydraulic lifters have bled down. That is what you want. Get yourself a remote starter or pull the plugs so you can turn the engine by hand easier and do this procedure as written by CRANE CAMS. Read it carefully as it also explains WHY you are doing the steps they outline. Absolutely no reason to expose yourself to hot oil spray and moving parts by doing it with the engine running.

Adjusting Hydraulic Lifters for Proper Preload

In order to adjust the preload the lifter must be properly located on the base circle or “Heel” of the lobe. At this position the valve is closed and
there is no lift taking place.You will need to watch the movement of the valves to determine which lifter is properly positioned for adjusting.
1. Remove the valve covers, and pick a cylinder you are going to set the preload on.
2. Hand rotate the engine in its normal direction of rotation and watch the exhaust valve on that particular cylinder. When the exhaust
valve begins to open, stop and adjust that cylinder’s intake rocker arm. (Why? Because when the exhaust valve is just beginning to
open, the intake lifter will be on the base circle of the lobe, the correct position for adjusting the intake.)
3. Back off the intake rocker arm adjuster and remove any tension from the pushrod.Wait a minute or two for that hydraulic lifter to
return to a neutral position. The spring inside the lifter will move the pushrod seat up against the retaining lock if you give it time to do
so. (If you are installing brand new lifters they will be in the neutral position when they come in the box.)
4. Now spin the intake pushrod with your fingers while tightening down the rocker arm. When you feel a slight resistance to the turning
of the pushrod, you are at “Zero Lash”. Turn the adjusting nut down one half to one full turn from that point. Lock the adjuster into
position. The intake is now adjusted properly.
5. Continue to hand turn the engine, watching that same intake. It will go to full open and then begin to close. When it is almost closed,
stop and adjust the exhaust rocker arm on that particular cylinder. (Again, when we see the intake almost closed, we are sure that
exhaust lifter is on the base circle of the lobe.) Loosen the exhaust rocker arm and follow the same procedure described before in

steps 3 and 4 to adjust this rocker arm

Thanks Jon. The Cranes method is very easy to understand.