The Stovebolt Site Forums The Shop Area Engine Shop 216 Valve Adjustment: Should I Do It?

Ol' Roy runs fine and I've driven the truck well over 10,000 miles in the last 4 years. This was after a slumber of over 5 years.

I know the valves haven't been adjusted in over 20 years.

Not having ever heard another 216 or 235 run in person, I'm not sure how much valve clatter is normal.

My questions are:

1. Should I adjust the valves on this engine or leave well enough alone?
2. Could there be any negative effects from adjusting the valves on an engine that's never had it done in modern times?
3. What would be gained from doing a valve adjustment?

1.- - - - -YES!

2.- - - -NO!

3.- - - - -Less noise, less wear from hammering of the components if the clearance is too loose (most likely) or less chance of burned valves if they're too tight due to valve seat and valve face wear.

4.- - - - -Shame on you for not doing routine maintenance. Valves need to be adjusted at least a couple of times a year unless the vehicle never gets driven!
LOL!
Jerry

4. Really? I've never adjusted valves in my life. Of course I've never had a vehicle that required valve adjustment, before.

I know you have a valve adjustment guide/instruction on this site somewhere. I'm sure I'll be asking a lot of questions when I get around to doing the adjustments.

Are any special tools required? Can I use my points/spark plug gauges to measure the valve clearance?

It depends on the condition of the rocker arm tips. If they're smooth, all you need is a feeler gauge, a 5/8" box end wrench, and a flat blade screwdriver. Rocker tips with a divot worn in the surface that contacts the valve stem make an accurate adjustment almost impossible. DO NOT attempt a running adjustment- - - -it's just a big waste of time, and it splashes oil all over the engine compartment. Get the engine up to operating temperature, pull the valve cover, and work quickly before it cools down. If you search the site archives for "companion cylinder valve adjustment" you'll probably come across at least one of the dozen or so posts I've made on the subject. Have fun!
Jerry

One of the side affects of the transition to hydraulic lifters so many years ago, nobody thinks about needing to make valve adjustment a normal maintanance item.

Suggestion:

If you’ve never adjusted valves before, do the cold adjustment procedure to get the hang of it. I believe there’s a tech tip here that lists both the cold and hot lash specs.

The way I remember the companion cylinder thing that Jerry is the number 7. The sum of the companion cylinders on an inline 6 will add up to 7.

#1 - Rotate the engine with the fan belt while watching the #6 rockers. You’re watching for the intake to open and close, and just when you see the exhaust start to open, stop. #1 is ready to adjust.

#2 - Same deal, but you’re watching cylinder 5 to determine when 2 is at TDC and ready to adjust.

If you use a dial indicator to do the Cold adjustment, it take the Rocker arm condition out of the equation. Set the dial indicator up and measure the free travel to set the lash.

I just cut and pasted Jerry's instructions here so I have everything in one place. When I'm ready to do this I'm sure I'll have more questions. I'll read up on this in the manual first.

-------------------------------------------------------------------------------------------------------------------------------------------------------

Here's an alternative valve adjust method I've used for over 40 years:

Companion cylinder valve adjustment

Turn engine by hand until you observe #6 exhaust valve closing. Continue turning until #6 intake begins to open. (Called "rocking", valves moving in both directions at once) This happens at the top of the exhaust stroke, with the piston at, or near TDC. #1 cylinder, both valves, can be adjusted at this point. Turn until #2 cylinder rocks, adjust #5. (Each time the engine turns 120 degrees, another cylinder will be at TDC, ready to adjust). Turn until #4 rocks, adjust #3. Next 120 degrees, #1 will rock, adjust #6. Rock #5, adjust #2. Rock #3, adjust #4. All 12 valves can be accurately adjusted in 2 turns of a stopped engine, hot or cold, and no oil spilling!

This works on any engine with an even number of cylinders. Easy way to remember which ones to rock/adjust: Write down half the firing order, then write other half underneath it: Chevy 6:

1 5 3
6 2 4

1 & 6 are companion cylinders- - -rock one, adjust the other. Same with 2 & 5, and 3 & 4. Quick, easy, and it works!
Jerry

-------------------------------------------------------------------------------------------------------------------------------------------------------

When I was younger an old hand told me his way of remembering inline 6 firing order, "15 is too young, 36 is too old, 24 is just right"

Maybe it's just my imagination, but the engine seemed to have more power after adjusting the valves.

That would make sense if the adjustment was loose. The intake valves wouldn't be opening as far as they would with proper adjustment, so not as much fuel-air mixture would get into the cylinders.

It's probably more about correct valve timing, rather than a minuscule change in lift. Late valve and/or cam timing increases top end horsepower at cruise speed- - - -early timing produces more low end torque. We used to alter cam timing with offset woodruff keys to account for different lengths of straightaways on the tracks we ran with the dirt car.
Jerry

I probably push my 235 and now 261 harder than most and it has a high-lift cam, which beats up the valve train more. So, I adjust the valves after each long trip. That's about 6,000 miles of loaded highway travel. I find that there will be a tight exhaust valve more often than a loose one. This is probably due to valve recession as they grind their way into the seat. I now regret not using the valve rotators but I thought they behaved oddly when I had the head apart. New Old Stock ones I subsequently bought behaved the same.Should have used them. Intake valves don't seem to change much and are usually loose if not on spec.

I adjust them cold and add 0.002 to the spec on the cam card. Yes they're noisy but they quiet down when it's hot. If I can't hear them at all when good and hot, like pulling over at the top of a long grade, I worry. I have yet to drop a valve or burn one so I must be doing something right.

I saved some old feeler gauges that are beat to a pulp from adjusting valves (SBC hotrods) hot and running to just to remind me not to do that. I have compared the dial-indicator reading with the feeler-gauge reading to see how notched the rocker tips are. Once you know that figure you can compensate for it. On Norton motorcycle engines I have used lash caps to prevent the rockers from digging into the valve ends i suppose you could do that on Stovebolt valves to have a greater surface area for the rocker to wear on. That would reduce the tendency to notch the rockers.It would change the rocker geometry some, maybe for the better with a high-lift cam.

Then there is the old fashioned EOIC method, tried and true for generations.

Start with No. 1 cylinder. Rotate the crank by hand or bump the motor with a bump starter (pulling the plugs makes the job easier). When the exhaust valve is just starting to open, adjust the intake valve for No. 1.

Then, continue moving the motor until the intake valve is fully opened and just begins to close. Adjust the exhaust valve.

Move to No. 2 and repeat, then the rest of the valves in order.

When I mill the 54/55 year cylinder heads .090" to get the same compression ratio as an 848 head, I shim the rocker shaft stands up 3/32" to retain the same intake valve geometry, and use a lash cap on the exhaust valve stems. The intake valves need to be recessed into the head the same .090 dimension to shroud the edge of the valves from the combustion flame, or the valves will burn quickly. Works like a champ!
Jerry