The Stovebolt Site Forums The Shop Area Engine Shop 216 valve adjustment

I have finally got my head and rocker arm assembly back on and have noticed something that does not seem right. Some of the rocker arms have a bit of play (I think the manual refers to this as lash) and some are tight to the point where I cannot wiggle them at all. The manual suggests that all valve adjustments be done when the engine is warm but it will be a while before I run this again and I do not want to leave things with excessive tension on them if they are not supposed to have that amount of tension. All the rocker arms are in the same positions they were in before I tore things apart and I think the relative positions of the rocker arms, push rods (which are new) and valve stems would still be somewhat close. I was also careful to put the valves back in the same place in the head that they came from. Am I worrying to much? Also, when you adjust a valve, I am guessing that you use a feeler gauge between the valve stem and the rocker arm, correct? Thanks for any help!

It seems that you're not aware that the valve train follows an
oblong shaped cam profile, which opens and closes the valves.
The valves are timed to open and close at a certain position
of the piston on that particular cylinder. The "lash" or
clearance is made with the valve train on the lowest part of
the cam lob when the valve is closed. You need to rotate the
engine so that each cylinder is on the top of the compression
stroke at which time both valves will be closed.
I'd suggest reading the basics of the four cycle engine theory,
which should clear up what I just posted.

Denny Graham
Sandwich, IL

Gazz,

Have you checked the Shop Manual?

Have you ever adjusted valve lash on a mechanical lifter engine?

Do you know how to set the engine to Top Dead Center on #1 cylinder?

here are instructions for 216/235/261 mechanical lifters

I understand that the valves are driven by the cam through the lifters and pushrods and that it all has to be timed correctly. I guessed that the valves being all closed before the rockerarms were replaced and only respond to the forces from the cam, the valves would sort of automatically find a somewhat correct position being that the cam is geared to the crank shaft as those parts were not removed and did not change. And yes, I did check the shop manual but they only talk about adjustment on a warm engine. And as you folks and the manual have mentioned, I am directed to adjust the lash. In either case there is no actual definition of what lash is, just that it needs to be adjusted to various dimensions, depending on whether it is an intake or exhaust valve. Again, I guessed that it is the gap between the rocker arm and the valve stem. Is this correct? And no, I have never adjusted the valves on a mechanical lifter engine before, otherwise I would probably know what lash is and probably would not have to ask these questions.

You understand this pretty well.

What is valve lash?

Once you have the engine/crank-shaft so the #1 cylinder is at TDC (both the #1 inlet and exhaust valves are open/loose-lash) now you can do a "cold setting" of half of your valves.

Then rotate the engine/crank-shaft 360 degrees until the #6 cylinder is at TDC. Then do a "cold setting" of the other half of the valves. Some people just set/adjust the cold engine valve lash to the "normal" settings rather than the cold settings (instead of adding 0.005" to the normal setting).

Start the engine and after its temperature settles, run it for another 30 minutes. Then reset the valve lash of all valves (using the normal/hot settings).

Good luck. Let us know how this works out for you.

I don't do it often enough to have it all in my head so I used the instructions on Tim's page with great success. I have it printed and stuck in my manual in the garage. I have found that the difference between cold and normalized settings is often very little. I normally only have one or two that need reset after the engine temp is normalized. If you've never done it before it can be a tad intimidating but follow the instructions on Tim's page and you find it's not rocket science.

Tim, what timing on this thread. I just installed my rebuilt head and was getting ready to adjust the valves. Thanks again for the info! Jim

There is at least one Stovebolt.com Tech Tip thread on setting valve lash - more info/ideas never hurts.

Of course you can adjust the valves on a cold engine and you must before starting it. You will find that the lash changes very little between cold and hot. The in between period though will have a varying lash.

I set mine cold to .004" over the normal operating temp settings to get it started after a topend rebuild and it starts and runs fine. I only have perhaps 3 hrs of runtime since and haven't checked/readjusted them yet. As well as it sounds and runs I'd wager it won't be too far off when i do

I have set valves cold, hot and running. tcleaderman has the best plan. Set cold with a bit more lash. Don't you love that? Book says .006 intake so add .005 and you get .011. Book says .013 exhaust. add .005 and you get .018. Easy. Start at TDC #1 use the "BB" on the flywheel and watch the valves on #1. set them both and then set all the valves that are all the way up. That will be six in total. Turn the engine until the "BB" comes up again. #6 will be at TDC and both valves will be up. Set both and the remaining 4 that will be up. Done! Start it let it get all the way up to temp and shut it off. Do it all again with out the added .005 and you should be perfect. Not hard. The feeler gauge should just drag when the adjustment is right. Snug down the lock nut about as tight as a spark plug 12 to 15 foot pounds and all should be good. That "lash" is the "take up clearance that allows the lifter to follow the cam and still allows the valve to set tight on the seat. Keeps the noise down, the compression up and lets the cam and lifter live a happy life. New motor with a new cam need a zinc additive to protect the cam and lifter for the first 20 minuets. After that you are good to run the oil of your choice. Yes it OK to run with the valve cover off to see that oil is getting to the rockers and flowing like it should. Put the valve cover on when you are done. If you are on a level surface and parked it won't make a big mess. If you have oil spray all over you have the rocker shaft up side down. And that is easy to fix. At least you will be able to see that all is good. No guessing when you can see it work. If I have missed anything some one will give us a shout and we will both be smarter. Works for me.

When you say use the "BB" on the fly wheel...

Where will I see the "BB"?

<CLICK>

http://www.pbase.com/dennygraham/image/110692357
DG

...click...
(ignore notes on video, use Tims steps above)

I read "BB" as an actual stamping.... still have plenty to learn.

In the original specifications, and in most after-market specifications also, the timing mark was referred to as "Ball" rather than "BB." So if you see reference to Ball, that means the bright ball embedded in the flywheel as shown in the pictures posted by others. Sometimes the ball would be obscured by grease and difficult to see, so you had to know where to look for it in order to clean it off.

Harvester