I have a 66 Mustang 289 that was making some light chattering noise on the Left side of the engine. A friend of mine told me it might be a loose rocker arm and that I should check the rocker arms for proper torque. I read that the torque should be between 18-20 lbf. All I did was take the valve covers off and torqued all the rocker arms down to 20 lbf. I tighted ALL the rocker arms down quite a bit. Now the engine does not even start. The starter is having a hard time turning over the engine. I am sure that I tightened ALL the rockers down too much. What is the proper way to torque the rocker arm stud nuts? Does the pistons each have to be at TDC for the rocker arms that you are adjusting or is piston #1 the only one that needs to be at TDC then you tighten the stud nuts all at once? I didn't adjust any piston at TDC. All I did was torque all stud nuts to 20lbf. Thanks for your help!!

 

You have the adjustable rockers, not the studs with a positive stop that the nuts get seated on a taper. The adjustment proceedure is a little different. Do a search for valve adjustment. If you have hydraulic lifters, you can set the valves with the engine running by backing the nut off until the rocker starts to clatter and then tighten it just until they quiet down. Then with the engine off, tighten the nut 1/2 to 3/4 turn more. It helps to have a set of old valve covers with the center cut out or use "rocker stoppers" to keep the oil from squirting all over.
If you have solid lifters, you'll have to make sure each lifter is on the base circle of the cam before setting the lash with a feeler gauge between the rocker and valve tip.
It sounds like you'll have to use the base circle method even if you have hydraulics. As with solids, with the lifter on the base circle (fully closed) tighten the rocker nut just enough to remove all the lash but not so far as to compress the plunger in the lifter. Spin the pushrod as you tighten the nut to feel the slack get removed but not so far that the pushrod won't spin at all. You'll feel some resistance but the pushrod will still spin. Then tighten the nut 1/2 to 3/4 turn.
Hope this helps.
Greg

 

Thanks Greg for your help. It does sound like I have adjustable rockers. I am going to take off one rocker and see if the stud is tapered. How can I tell what kind of lifters I have (Hydraulic or Solid)?

"If you have solid lifters, you'll have to make sure each lifter is on the base circle of the cam before setting the lash with a feeler gauge between the rocker and valve tip."

How do I make sure the lifter is on the base circle? Is this TDC?
Thanks Again!

 

What I like to do when setting valves is start at #1 cylinder. Bump the engine over and when the exhaust valve just starts to open, set the intake. Then bump it over until the intake fully opens and then some just until it closes, set the exhaust. This method puts the piston near BDC when setting the valve, the start of the exhaust stroke when setting the intake and the end of the intake stroke when setting the exhaust. One full revolution of the crank and 180° on the cam.
This method works on any engine and you don't have to worry about having the crank on TDC to set specific valves then turning the engine and setting other specific valves.
To determine if you have solid or hydraulic lifters... when you just remove the slack in the valve train, use a hammer handle (or something similar) to hold pressure on the pushrod side of the rocker arm. If the clearance increases (or feels slightly spongy), you have hydraulics. If you turn the adjustment 1/2 to 3/4 turn more and you have no compression (solid lifters will hold the valves open) and the engine won't start (the condition you have now) back off the adjustment just until you have a slight amount of slack in the pushrod. Sometimes you have to let the lifters bleed down for a bit. If you have solids, you'll have to set the valves with a feeler gauge to the recommended clearance. Chances are that you have hydraulics.
Hope this helps.
Greg

 

Greg is methodically technically correct. After doing about 4 valves like that though, you get tired of bumping the engine over every time you want to set a valve. Here's my abbreviated procedure:

take both valve covers off, and set the lash as described above for all 16 valves, except the ones that are obviously undergoing lift. Rotate the motor over 180, and set the rest of them. Rotate the motor a couple more times and check to see if they feel firm, making sure none came loose (you adjusted them while being lifted). This procedure requires a maximum of turning the engine over 4 times.

Again, if you've had to set lash as many times as I have, it gets annoying to go back and forth. To make the adjustment you set not shake loose, use threadlocker blue inside the adjusting bolt on the rocker stud, making sure to dry the oil off the stud so the threadlocker will adhere. This way you can easily remove it one day if you need to, but it won't vibrate loose and make you have to set the lash again. I set mine 3 times in 3 weeks before somebody (tech support @ Jeg's) clued me into that little nugget of advice. TK

 

macguyver & TorqueKing
Thanks very much for your time to respond. I set my valves the best that I could using your instructions and the Stang now starts. I drove the car to Macon, GA tonight after setting the valves (about 4 hours round trip) and she drove great. She seams to have more power than before. I still get a slight tapping sound and I am sure I just need to tighten one or more rockers. I just need to figure out which one is tapping. The tapping is worse when I go to pass but is ok when accelerating from a stop but I do hear it when I am under the hood. I will check them out again this weekend and get some threadlocker blue.. Both of your instructions are alot better than my Haynes manual that I have. Thanks for your support!!!!

 

This site is great, I find new stuff and sites for the Ford truck every time I surf the web. So I was looking for some clarification from the Motor manual I had that lists the positive stop and non positive stop studs and how to set them. I have the non-positive stop studs and the procedure as listed above with the 1/4 turn of the crank following the firing order of the engine. The manual is not clear, and from the previous posts am I to believe that I turn it a 1/4 turn for every valve or about 16-1/4 turns of the crank? Set both valves of 1 at TDC then turn 1/4 turn go to the intake valve and then another 1/4 turn and do the exhaust valve on 5, 1/4 turn and so on through all 8? It is amazing how many people think the only way to set rockers is with the engine running, proof that people don't like to read instructions?

 

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Most manuals will specify that you set it at TDC and do certain valves, then turn the crank one full revolution and do the rest. I sometimes do that, but the other method I often use is to watch the valves on a particular cylinder as I turn the crank; when the exhaust valve just finishes closing and the intake vale just begins to open on a particular cylinder, then that cylinder is at TDC of its' exhaust stroke and it's opposite cylinder is at TDC of the compression stroke and is in postion to have both its' valves set. An easy way to see what each cylinder's opposite is, is to look at the dist. cap and see what cylinder is directly across the cap from it. Another is to go by the firing order: Take the first number and it's opposite cylinder is the fifth, the second and sixth, third and seventh, fourth and eighth. So 18436572- would be #1 & #6, #8 & #5, #4 & #7, #3 & #8.

Hope that's clearer than mud!