Valve train clatter

charliecurrie

Well-known member
Just installed 264/274 112 cam from Vintage Inlines and I can't get the valve/rocker adjustment correct - quiet.

Stock '66 200.
Rebuilt '66 head
Adjustable rocker assembly
302 valve springs
New Sealed Power hydraulic lifters
Stock pushrods - ~8"


If I adjust the valves according to the CI tech recommendation the valves hang open.

If I back the adjustment off until I get maximum vacuum and smooth idle, it clacks and taps annoyingly loud.

Suggestions?
 
I can't get close to zero lash without the valves hanging open. It creates a huge vacuum leak and uneven / surging idle.

If they're not clacking / ticking they're not closing.

When everything is lose and noisy, I have 20+ in of vacuum and a rock steady needle on the gauge and a rock steady idle at 500 rpm in neutral.

My rockers are the shaft mounted non-roller. This valve train worked fine with the stock 53 year old cam and lifters. Well fine for its age and worn lobe the fuel pump lever rides on and a couple of lazy lifters.
 
Have you tried to isolate the problem to a single valve/lifter? Do all the lifters depress?
 
It's every cylinder, every valve...so, I suppose, every lifter.

Is it possible none of the lifters are depressing? Although, my buddy who helped with the install, depressed one of them for no reason before I put it in.
 
How is your oil pressure???
Your valve springs are not involved with this condition, but you need close to 100# seat pressure.
Sometimes it takes several minutes to have the hydraulic lifters to respond to a half turn of adjustment from zero adjustment.
 
Oil pressure is good - no gauge - but the light doesn't come on. And, there's plenty of oil flow to the valve train - easy to see with the valve cover off.

Oh, we've run it longer than several minutes and the valves never close completely. But, as soon as you start backing off the adjusters you can see - vacuum gauge and tac - and hear and feel the improvement. We do the adjustment with the engine running.

All I changed was the cam, lifters, valve springs and timing set. Didn't have this problem before the change.

It runs down the road just fine. A noticeable improvement. Idles smooth at 500 rpm in gear.
 
Take each cylinder one at a time starting with #1
Turn the crank clockwise until the EXHAUST valve just begins to open and stop. Then adjust the INTAKE valve with 1/2 turn past zero lash.

Now turn the crank clockwise again till the INTAKE valve opens and begins to close. Just as the intake valve closes stop and adjust the EXHAUST valve with 1/2 turn past zero lash.

Continue the process on remaining cylinders 2,3,4,5 and 6

Zero lash is when you no longer have rocker movement by hand and you can feel the pushrod starting to press down on the lifter plunger.
 
This is a wild guess, but is it possible all the lifter plungers are bottomed out & the lifter plunger has not pumped up to the snap ring.
Take the rocker arm assy off the head.
Remove the distributor & with a drill spin the oil pump shaft to get line pressure. That will get the plungers to the top of travel.
Reinstall rockers assy with the adjusters backed off & adjust each valve. Good luck.
 
Like I've said above, this has been done - multiple times using this and other procedures which produce the same final setting. And, the adjustment at zero lash, or zero lash plus, hangs the valves open - all of them.

This is not the first time I've adjusted the valves on this car - two engines and two different head and valve train configurations - never have had a problem...until now.
 
wsa111":2rj5yzlv said:
This is a wild guess, but is it possible all the lifter plungers are bottomed out & the lifter plunger has not pumped up to the snap ring.
Take the rocker arm assy off the head.
Remove the distributor & with a drill spin the oil pump shaft to get line pressure. That will get the plungers to the top of travel.
Reinstall rockers assy with the adjusters backed off & adjust each valve. Good luck.

Thanks - appreciate your continued input.
 
Did you degree the cam ?
Is the cam spacer on the cam behind the pin with the inside bevel toward the journal, not to be confused with the cam retainer ?
Is it possible that the valves are closing and the the cam duration is making lower vacuum and rougher idle than you expected ?
Loose lash will get better vacuum and better idle because it cuts down on duration, cannot run it that way .
 
drag-200stang":2c424hbs said:
Did you degree the cam ?
Is the cam spacer on the cam behind the pin with the inside bevel toward the journal, not to be confused with the cam retainer ?
Is it possible that the valves are closing and the the cam duration is making lower vacuum and rougher idle than you expected ?
Loose lash will get better vacuum and better idle because it cuts down on duration, cannot run it that way .

All good questions. Thanks.

At this point, I have no other option than to pull it apart, inspect everything and put it back together.
 
Update:

Replaced adjustable rocker assembly with non-adjustable rockers and push rods. Obviously, it quieted down, but ran like crap. Neutral idle was ok but in gear it was making some odd noises and idled ruff. Vacuum was lower also.

Had to put the adjustable rockers back on and put up with the clatter.

I'm thinking it has something to do with the lifters. Thinking I'll replace them and put in the stock cam I have on the shelf.
 
It looks like the lifters are not bleeding down after adjustment.
They are acting like solid lifters.

Take one out and see if you can push the plunger down away form the retaining clip.
If so measure how much travel you have.
Most anti pump lifters only have about .100" worth of travel.
 
pmuller9":2s3h23pe said:
It looks like the lifters are not bleeding down after adjustment.
They are acting like solid lifters.

Take one out and see if you can push the plunger down away form the retaining clip.
If so measure how much travel you have.
Most anti pump lifters only have about .100" worth of travel.

That's been my suspicion.

What would cause them to act like that?
 
I don't know why.
I'm hoping you find the reason when you take one out for inspection.
 
Can you depress the lifters? Is it possible that when installed the lifters were fully pumped to the top and can't bleed down now?
 
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