I know this has been posted before but I would like to make sure it is still Accurate. Specs for stock Cam Lash is .019 in the Ford Shop Manual. Equivalent to 90 degree counter clockwise rotation of the Adjuster Screws from Zero Lash ? This would apply to worn Rocker Arms where the Feeler Gauge would no longer be Accurate?. Is .019 still considered to be correct or is .020 or .021 more realistic because of changes in material used when these Engines have been rebuilt over the Years?

  

Im sure it would be fine Mark. Its the way I do it on mine [god knows how worn they are ]  Dont think you have to be super accurate. 



"Came too close to dying to stop living now!"

The "1/4 turn" or 90° from zero lash method described by Walt Nuckels will be more accurate and consistent across all the cylinders than using a feeler gauge, if the rocker faces have a pocket worn on them over long time running. .019" is fine for a stock camshaft. Aftermarket or performance camshaft is going to be different.

What you end up with though, is also dependent on whatever start point is considered to be zero lash. I experimented a bit and loosened the rocker screw enough so that the pushrod will spin back and forth freely with oily fingers, and then made the 1/4 turn loose from there. With a stock engine I'd suggest measuring engine manifold vacuum on a mechanic's gauge beforehand, if the lash is set too tight engine vacuum will drop off noticeably.


If the rockers and shaft are scored and worn and loosey goosey it will be tough getting a consistent setting.

 Its like words from a higher power....



"Came too close to dying to stop living now!"

The  Y block sounds like a politician the answer can be what ever  you want it to be!  

Valve lash is another tuning tool.  While 0.019” is the accepted number for a stock Y camshaft, non-stock camshafts can benefit from more or less lash depending upon the camshaft itself and the results you are trying to obtain.  The Isky E4 camshaft in my 272 does like a little more additional lash just to make normal driving better.  When set to the tight side, the engine had a slight hesitation on normal take off and increasing the lash eliminated that while also increasing the idle manifold vacuum.  There’s also less rump from the camshaft with the looser lash setting but with that comes some additional tappet noise.  Regardless of the lash setting, it’s important to be consistent in the measurement or the setting of the lash so that the end results can be more accurately evaluated.

Lorena, Texas (South of Waco)

LOL, well I try to help but, as far as divine intervention, as they say, "your mileage may vary".

I took a closer look at all the original rockers after replacement and what surprised me was how what appears to be even just a small amount of wear on the face can interfere with accurate lash adjustment. A few thousandths one way or the other probably isn't the end of the world but getting them all consistent makes for a smoother running motor.

It may be the wear and galling that's typical on the rocker bores and shaft has an outsize effect. All the slop or excess clearance has to be taken up before anything moves. The "1/4 turn" allows for some of this, but not all of it.

With fresh valve springs and the new rockers, shafts, pushrods &c I realized a 5 to 10 psi compression improvement in several cylinders, everything is evened up now.

I  adjusted the Valve Lash this Afternoon. I found about 5-6 with little or no Lash. Used the 1/4 turn System and verified as best Possible with Feeler Gauge just to double Check. I bought this Sunliner about 2 Months ago.22,000 Miles on the Car since Frame-off in 1985. So far replaced the Intake with a "B", 390 Holley, 1957 Distributor, and Aluminum Rad. Couldn't get it to Idle even with the new Carb. No wonder with several Valves never closing. Straightened out the Linkage that I was asking about in One of my Previous Posts. Well it runs like a Watch now. Stays cool with the Aluminum Rad. After going over this car since I bought it I realize now it probably has seen little if any Use for at least 5 Years or so. Been in good dry Storage. For a 33 Year old Restoration its in excellent Shape. Just needs some Mechanical TLC which is really coming along well now. Canadian built Car with Canadian only Exterior Color Carousel Red, Power Seat, Power Top, Power Windows, Power Steering and light Tinted Glass. I will be selling my Town Sedan. Wife wants to use the Garage come next Winter. Not sure why she wants to park in the Garage???? 

  

When using the 90° turn method keep in mind, just so we're clear, there's no point to using a feeler gauge it's not needed or even wanted, don't change the resulting gap after you make the turn. Valve Lash will tend to get tighter over time. Valve recession for example.

Garage - well, that's just crazy talk!!!

Whoa whoooaaa..! Mark you have a Sunliner..and have we seen pictures of this...?? 





"Came too close to dying to stop living now!"