OK, I have another procedural question that may seem basic to a lot of you.

When I first gor my car, I asked the mechanic how to adjust the valves, and he said to turn the adjuster down till it touches the push rod and back it off a quarter turn. Stuff I read made it seem alot more technical than that, though one article I read seemed to imply the same thing (in a long winded way).

Eventually I adjusted the backlash using a feeler guage according to the specs in the manual, and the proper adjustment had more backlash than the first method.

Problem is, the manual says to make a final adjustment with the engine warmed up and running at idle speed. How is this done? You must need a special feeler guage or something. I seem to remember someone mentioning a "go-stop-go" guage or something. Any help is appreciated! JR

 

Here is a procedure that was posted a few years ago, I dont remember by whom but it works well.

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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, .050” X 1.54 = .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 minuets of a clock face. This number is .001283” = 1 minute of clock face rotation. Thus 15 minuets of rotation will =.0192” 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 quit 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 a B1 or B2 suffix will be a 1.54 ratio rocker and all those without suffixes will be 1.43 ratio.

 

Thanks for the info, Merc. This is actually one of the articles I read...since 90 degrees is 1/4 of a 360 degree circle, it seems to verify what my mechanic said about backing off a 1/4 turn after the adjuster hits the valve (i mispoke earlier when i said pushrod).

Thing was, after using using that method, the gap on the valves measured out at .010 - .012, and the valves were extremely quiet....even non-solid lifter guys were amazed at how quiet my old engine was. Was this because the valves were adjusted tighter than spec?

When I recently used my feeler guage method at .019 (from the manual), I started getting that faint ticking sound that I've always associated with solid lifters...not that that means anything. I don't see the excessive wear that the article is talking about, so maybe I'm ok with the guage.

Of course, I totally respect the mechanic who gave me the advice, so I'll keep that in my bag of tricks.

 

JR, i adjust mine at a tight squeeze cold at 0.15, a tight squeeze would be to where you can feel the gauge drag or pull out, then hot it will be between 12 and 15 thousandths....Two adjustments aren't neccesary on Yblocks, but like i've told many people, if rocker shafts are worn it's only a waste of time, but even when i was a very novice novice mechanic at 10 years old i could tell even then, yes i started very young with this stuff. I remember the time when me and my Grandfather rebuilt a 331 V8 in a 1953 Cadillac when i was 12, that engine had hydraulic lifter and was about as modern as engines made in the 1970's!!! I wouldn't steer you wrong. The specs your mechanic gave you (tighten till touch then back one quarter turn), that is the basic adjustment for the 1980's Chevy 350 V8, and i have no idea why on those late chevy V8 350's they use an adjustment because that engine has hydraulic lifters, olds, pontiac, and Cadillac just bolt on, and are premeasered, it's a good average true, but that's a tad tight for a Yblock...Janet

 

Thanks again, Janet. I've received alot of good information here.

 

I'd take Walt's word over J40s anyday, thats who posted
the original that 256merc put up. But it wasn't posted here
until I did...

SteveL

 

I agree with canzus.

I do like to run mine on the "loose" side. Mine are gapped at least .019", I'd rather they be loose than too tight!

I run the aluminum valve covers and they really keep it quiet.

Kevin Bigwin