VCCA Home Forums TECHNICAL - 1945 AND NEWER 1961-1964 What is your method of adjusting valves? ('62 235)

I just wanted to find out from anybody on here who has adjusted the valves on their 235 straight 6 how they went about doing it and any pointers they have.

Is there anything special to consider with this engine? Should I try to precisely adjust them to the .006/.018 specs listed in the book?

Mike

I like to adjust them with the engine off, start with the engine at TDC on #1, some manuals will show which intake and exhaust valves can be adjusted then turn the crank one turn to TDC #6 and you can adjust the rest of them. The other way is bring the rotor to point to each plug wire and do both valves on that cylinder.

I adjust them with the engine running as the shop manual states.
I have tried the not running method and you always end up with one or too set too loose.

A 1962 235 car would have hydraulic lifters. Those I would set with the engine hot and running and change the adjustments very slow.

If its a truck it will have solid lifters. The intakes should be .006" to .oo8" and the exhausts are fine at .015". The .018" setting would be for a heavy duty (hard working ) truck. Will be awful noisey at .018" You could even go down to .014".

I also adjust the valves with the engine running....as described in the shop manual.

It is a truck. Right now its "aweful noisy" as was mentioned. I have never adjusted valves while the engine was running. How do you do it?

Thanks for the responses.

Mike

Detailed instructions should be given in your shop manual.

I've read over the manual again. It says to remove the rocker arm cover and then run the engine at fast idle to get the oil temp constant, check manifold bolts etc, lubricate valve stems, and then it says "adjust valve clearance as follows: Intake .006 Exhaust .018". Then install rocker arm cover. It never says whether to adjust it while running or not. Frankly it doesn't appear to say much at all. With the valve cover off wouldn't it throw oil everywhere?

How should I approach this? Suggestions?

Mike

Ok - First remove the rocker arm cover and run engine. With engine running there should be oil dripping from the rocker arms, the head and rocker arms should be wet with oil, and some oil coming up thru the little holes on top of the rocker arms. It was common for the oil passage coming up thru the blaoc and head to sludge up and the arms would run dry. This makes for really noise rocker arms due to wear. This ehgine will not be squirting oil all over like a small block V-8.

To adjust the rocker arms you will need a 5/8" wrench. I prefer an off set 12 point box wrench. And a stubby screw driver with a wider blade. A set of feeler gauges.

Set the intakes first. They are the tall straight valve (stems).With the engine at a slow idle pass the correct siz feeler blade between the tip of the valve and the rocker arm. If the gap is too tight is will be difficult to slip the feeler thru the opening . If too loose it will pass thru with no resistance. What you want is make the adjustment so a little drag can b felt. Repeat on the intakes. Will take a little practice to lossen the lock nut, turn the adjusting screw slightly, tighten the nut and recheck the results.
Repeat on the exhaust valve.

If the tip of the valve has worn into the surface on the rocker arm is will pich the feelers and make a perfent adjustment impossible. The rocker arms should then be resurfaced in that area or replaced. Temporaily you could just then set the valve a little tighter.

If it has been run with out oil getting "up-stairs" the arms and shafts should be replaced.

I guess the manual assumes you will do it with the engine running I have never seen a Chevrolet mechanic do it any other way Chvrolet claimed that was the advantage of the over head valve Chevrolet engine, valves could be adjusted accurately with the engine running. On the flat or L head cars it had to be done with the engine stopped.

Since the manual did not state to turn off the engine before adjusting the valves, you do it with the engine running as Gene mentioned.

Just in case you don't get it the first time......
like the man said:
Get the engine up to operating temperature, set the idle really slow, take the valve cover off...and you won't get scalded with hot oil like you do on a SBC. A very slow idle, start with the front, do all the intake valves, with a single feeler gage, a boxend wrench and a large slotted stubby screwdriver or if you are really into 235 and 216 engines use a valve adjusting tool. (that is how I do it)If the feeler gage starts gets little half moon dents in it STOP and resurface the worn rockers. Then start again. You gotta get the hands in sync, do the feeler gage, lay the feeler gage down, the boxend loosens the lock nut and the screwdriver tightens the adjusting screw or if the lash is too tight, loosen the screw, and lock the lock nut with the boxend, pick up the feeler gage after you hunt for it, repeat till the intakes are ok, leave the engine running so that the exhaust valves will stay good and warm! Then change the feeler gage and do the exhaust valves. I usually cool off with a beverage of choice after the intakes, and then do the exhausts. After 50 years you may get a little clumsy and it may take about twice as long as it did 30 years ago. Don't worry just take as long as you like, after all it is your engine.......

By the way if the engine is not warmed up to operating temperature and you get the valves too tight they may burn a valve and/or miss, with mechanical lifters, if you do the lash adjusting cold leave them a thousandt or two loose. Hydraulic lifters are adjusted a little different. I set my mechanicals so that when the engine is cold it has a little regular Chevrolet tapping sound, then after 10 or 15 miles it is so quiet you won't know it is running at an idle, if everything in the engine is good. If a valve starts tapping very loud after a few trips check for a locknut that has backed off, it happens sometimes.

Hi acewmr,

Your figures are off for the value of the valve setting. It should be .006 and .008.

Thanks for all the great advice. I will get on that this weekend (hopefully it won't rain).

I just glanced at the book again and the adjustments are .006 and .018. Someone mentioned I should adjust the exhaust to .014. Where do yall adjust them to?

Mike

"If its a truck it will have solid lifters. The intakes should be .006" to .oo8" and the exhausts are fine at .015". The .018" setting would be for a heavy duty (hard working ) truck. Will be awful noisey at .018" You could even go down to .014".

Gene gave you good advise on his post here in quotes.

Thanks again for all the help. I'll let yall know how it goes. One last thing, when you use the feeler gauge do you have to remove it before the rocker arm comes back up to the valve? Hopefully I won't have any more questions.

Mike

...NO - the feeler stays until the adjusment is completed.

Mine, don't stay in position, I check the lash thru several valve cycles, adjust, then recheck the lash........ this operation isn't rocket science.

I don't know if your manual states this but you should check and adjust (as needed) the ignition timing after setting valves.

I think you have it confused with setting the timing after adjusting the ignition point gap.

I adjusted the valves back to spec, but its still ticking. I did find that oil was getting up there and the exhaust valves were too tight. What else could be causing it to tick?

Mike

Wear on the rocker arms and valve stems.

Could the timing cause the engine to tick (like a diesel)?

Mike

No, but setting the valves at .018" will. That is a setting for heacy duty big truck use. When that cam was used in a passengeer car or small truck the settings were .008" and .015"
The .018" was used on the heavy duty trucks with exhaust valve rotators.

If it were mine I would watch for a NEW rocker arm assembly on ebay. Chevrolet sold the entire assembly, arms, shafts, etc. as a unit and I have seen them on ebay. The one you want fits from 1959-1962.

I set the intakes to .006 and the exhausts to .015. Can I tighten the exhaust valves a little more or would that cause damage to the valves?

Mike

Well yes and no. For 1937 and up the recommended settings were .006" to .008" for the intakes and .013" to .015" for the exhausts. I generally set may exhausts at .014" and have never had any burnt valve problems. A too tight setting will cause the exhaust valves to burn. Make sure the engine and oil are completely "hot" when setting the valves. If not hot the valve setting will become less as the temperature increases.
If the valve has worn a pocket into the rocker arm the feeler will get pinched in the pocket and make the adjustment feel tighter than it is. You can easily inspect the surface on two or three of the arms to check for wear.

I should have noticed this before, but there are two distinct clicking noises. One is like a sewing machine (I recon thats the valves). The second is a click about every half second at idle (Roughly one per revolution as best I can tell). Could that be just a valve or is it something else?

Thanks for all your help Gene.

Mike

Without hearing it its kinda hard to tell but some times they just "do that".......Are the push rods spinning when the engine is running? (sometimes one or two will not) or you could try lubricating the valve guides with a light oil. Either pour the oil through the carburetor throat with the engine running ot squirt oil on the top of the valve guides by going between the coils of the valve springs. Also oil the sockets on the top of the push rods.

Yes when there is a bit of valve sticking or there is a weak valve spring the valve will not come up as fast as the push rod is going up and down, then you will have that CLICK !

The click on every other revolution (or less frequently) is likely a bent pushrod hitting the side cover. It is more of a clunk than a tick. It is easy to check to see if all the pushrods will rotate with engine idling or when not running and the rocker arm not loaded.

If you can't find the source of the sound then use a large screw driver or metal rod or automotive stethoscope. Put one end next to your ear and the other at various places on the engine. You will be able to hear many sounds typical of a good running engine. And occasionally hear a sound that is not normal and be able to pinpoint the location.

For me and my hearing, or lack thereof, I use a moderate length of garden hose, one end on the engine, the other end stuck in my ear.

Nearly anything that transmits the vibration will work. Just remember the first hearing aids were tapered animal horns. Then granny had one of those metal replacements.

WHAT ? ? ?

It turns out the number 2 intake valve must be slightly bent because it is the only one that does not turn. It also it the only one that does not have a flat rocker arm surface (dents the feeler gauge). I did have to redo some of my adjustments so now it sounds a lot better.

Since the engine seems to be running well is it better to leave the one valve alone or try to fix it?

Mike

If you suspect a bent valve, I believe a compression test is in order, before any more engine damage occurs.

I would bet my life its the push rod that is bent. The valve probably stuck at one time and hit the piston. Without removing the head (and valve) there would be no way to tell if the valve is bent.
Take the push rod out and straighten it....roll it on a flat surface to test.

I have found that a flat sheet of glass is excellent for testing bent push rods.