I tried adjusting my valves twice today bringing each cylinder to TDC on SC. I judged this by starting with #1 and the timing marks. Then proceeded through the firing order making sure the crank was at one of the 90 marks with both valves closed. Some of the cylinders seam to be out of time but I assumed the engine turned too far, and I just bumped the engine until the exhaust/intake opened and closed and the valves were at rest with the crank at a 90 degree mark.

I was tightening the valves to 0 lash then loosen 90 degrees to get to .019. (See the instructions below.) I checked #1 and #4 with feeler guage and they were close but the valves rattled terrible. Last year I adjusted them with a feeler guage and the engine sounded like a sewing which to my understanding is perfect. The feeler guage is a PITA. What I am doing wrong? Is zero lash when rocker will not rattle or when the valve moves?


Adjusting Valve Lash on a Y-Block
Y-Block enthusiast, let’s talk valve lash. As y-blocks have no hydraulic lifters, it is necessary to adjust the tappets quit often. Unfortunately, the use of a feeler gauge is satisfactory only if the rocker faces are in good condition. If the rocker faces have wear pockets, from contacting the valve stem, the use of a feeler gauge will provide results which are little better than calculated guessing, as the gap will always be greater than the thickness of the feeler gauge due to said condition.
About fifty years ago when solid lifters were most common, a tool was developed for adjusting valve lash, utilizing a dial indicator, called a P&G Valve Gapper. These tools were supplied with specific adapters for different makes of engines, including y-block Fords, by P&G manufacturing Co. of Portland, Or, but to the best of my knowledge they no longer exist. Can anyone expand on the existence of this company or a source of this tool, or parts thereof? I have found a few at swap meets but not in the last decade. This is the finest tool ever developed for adjusting solid lifter equipped overhead tappets as anyone who owns one would testify.
For those of you without the luxury of such a precision tool, may I suggest a very satisfactory method alternative to feeler gauges anyone can perform without special tools.
The tappet adjust screw is 20 threads per inch thus 1 full turn represents .050 of linear travel. It works just like a micrometer. Multiply 1 turn of travel times existing rocker ratio. Example, .050x1.54 = .077. As you can deduct, one full turn of the adjust screw used in a 1.54 ratio rocker will represent .077 of tappet clearance. Now divide one turn of tappet clearance i.e, .077 by 60 as in the 60 minutes of a clock face. This number is .001283 = 1 minute of clock face rotation. Thus 15 minutes of rotation will =.192 Very close to .019 which is the specification for valve tappet clearance on 292 and 312 engines. 15 minutes clock rotation = 90 degrees rotation, an increment most auto enthusiast can easily estimate quite closely.
Get into the engine, with the lifter all the down obtain some tappet clearance then carefully rotate the adjust screw clockwise to obtain .000 valve lash. Just touching but not depressing the valve. Now rotate the adjust screw counterclockwise 90 degrees. The resulting clearance should be very, very close to .019 regardless of rocker arm face wear.
If adjusting 1.43 ratio rockers rotate the adjust screw 16 min. of rotation ccw. To obtain .01906 clearance. Very, very, very close.
In order to determine the ratio of said rocker, observe the # on the side. 1.54 rockers are marked ECG 6564-B2 or “B1 I am led to believe any rocker with B1 or B2 suffix will be a 1.54 ratio rocker and all those without suffixes will be 1.43 ratio.
Walt Nuckels 12/31/00

Its kind of a "feel" thing.0 lash is when you can't turn the pushrod with minimium effort.I turn them as I am tightening the rocker arm screw and when they can't be turned using my fingers that's what I use as 0 lash.Are you sure you are using the correct firing order and engine rotation?15486372 and rotation is clockwise when viewed facing the front.#1 is the front passenger side.I only ask because its not hard to forget or go out of order in the firing sequence.If you are working with worn rocker arms the feeler gauge will not be accurate.You are best to use the 1/4 turn method. Setting valve lash accurately is one reason to have a timing tape on the damper.They are marked in 90 degree increments so you dont have to guess where you are in the firing order.

  

You really need to be on the cam base (TDC on compression stroke). Also, zero lash is when the "click" no longer feels or sounds when the push rod is moved along its axis.

As has been brought up, it’s important to be on the base circle of the camshaft when attempting to adjust the valve lash. Here’s the link to a past thread which goes through several different methods for tappet adjustment.http://forums.y-blocksforever.com/Topic8614.aspx

Lorena, Texas (South of Waco)

Thank y'all for the prompt replies. I was numbering the cylinders incorrectly (a little embarrassing.) I will attempt it again with a cold engine using the effort to turn the push rods as the indicator of 0 lash.

My rockers do not have a B1 or B2 prefix. Is this an indicator the rockers are 1.43 and they need a 1/4 turn plus a minute loosing or is a 1/4 turn good for both ratios.

Incorrectly numbering the cylinders is a common error.I think 1/4 turn would put you very close to required clearance.Working with used rockers is very difficult to get exact clearance unless you use a dial indicator for each one.

  

Just finished and the truck sounds perfect and the slight miss is gone. I am comforatable they are adjusted right. Thank y'all again for all your help. Now on to getting the choke adjusted. It has dipped below 75 in San Antonio and I need for the first time in 9 months.