Good job, however when you look at higher lifts things change, I will always do the check on the setup I plan to run (well I will now), I plan do do another test with shorter and longer push rods to see the change. Has anyone adapted a FE rocker? (I might), it looks like narrowing and bushing will make them fit.

If I remember right, FE rockers are 1:7 ratio, Mummert has them for the Y Blocks.

Mummert's 1.7 ratio are only for aluminum heads.
I have seen where someone in South America adapted some roller rockers from another engine.  You probably will not find something that only requires modification to the rocker arms.  It will probably require modification to the pushrod holes in the heads, as well.  You will also have to pay attention to the relation of the tip to the valve.
Everything else equal, a longer  pushrod results in a higher ratio and a shorter pushrod results in a lower ratio.  You can see this by looking at the rocker arm and observing the relation of the adjuster screw to the shaft center.  As the screw is turned in, the distance from the adjuster center to shaft center increases, reducing the ratio.  Assuming geometry is currently optimum, changing from one to the other will require a correction to geometry.


Lawrenceville, GA

I think it needs smaller diameter shaft and some offset setup to tune the tip lenght right for the Y.


Hyvinkää, FI

Better photo of the oil channel cut into the rocker

Charlie: I doubt very much if you have ever checked a rocker arm for ratio,but yet you chose to criticize people who have made the effort to do that.I have been to Ted Eaton's web site many times,and it is very apparent that you are using his effort's to criticize other peoples effort's,very handy.I totally respect Ted's work to give us information about y-blocks when I get a y-block mag in the mail Ted's article is usually the first one I read.Any engine builder that can put John Kasse in 2'nd place has to be very knowledgeable.But no one gets it right100% of the time.Ted's rig for checking rocker arm ratio does not maintain the angles and pivot points of an assembled y-block engine.The jig I use maintains all the angles and pivot points of a fully assembled y-block engine About 10 years ago I was going to send an article to Bruce for his mag.I didn't do that,now I will send the info to Ted and hope to hear his thoughts about checking rocker ratio's.
      This discussion has prompted me to clean the dust off my jig and put it to work again.For this ratio test I will use a ECG 6564-A2  1956 rocker arm and a long EAN adj.screw.This time using.300" push rod travel and the adj. high enough so that no threads are visible under the body of the rocker arm, the valve  moves .476" divided by .300"= 1.586 to 1 ratio.The rocker screw is then turned down 10 full turns.Moving the push rod .300" the valve moves .485" -- .009" more than the first test .485" divided by .300" = 1.616 to 1 ratio.Charlie your theory about rocker arm ratio is useless if it can't be proven with legitimate tests
             
                  john2747                       

There was no criticism and it's not my theory.  If you just google rocker ratio and look at the explanations and pictures, you will see that the ratio is the distance from valve tip to pivot center divided by the distance from pivot center to pushrod contact point.  The ratio does in fact decrease as the adjuster screw is turned in..

Your setup performs the check with valve and rocker dimensions setup as they would be on an actual engine which does give a better picture of how it all interacts.  I bet when it is actually on an engine, it changes yet again because of the pushrod and lifter angles.  What your test does not take into account is rocker geometry.  Simply adjusting the screw may not be an accurate way to perform this check since geometry will not be correct for both and that is going to affect the lift result.  It would be interesting to know how the effective ratio works out with actual Y block dimensions and when geometry is correct.  That would make for a good article.


Lawrenceville, GA

Over the years I have played with rocker arm geometry and designed and built my own true roller rockers. (no they are not for a Y-Block or any other Ford product) Lowering or raising the stands do make a difference as does the use of lash caps when making adjustments. All my work was done on an exact mockup engine with light weight test springs and the camshaft I was planning on using. By playing around with it I was able to see slight changes and after flowing my cylinder head the slight amount was not worth the trouble as for me anything over .600" lift was not doing any good and I maxed out at .615".
With that said the correct geometry is easier on parts especially when you do not have roller tips from what I understand. My original reason for making roller rockers was to eliminate valve guide ware which was actually occuring because the geometry was off. Good Luck.

56 Vic, B'Ville 200 MPH Club Member, So Cal.

Ok, here's the test, used 3 length push rods, 
1st 8.000 this opened the valve .556
2nd 8.250 this opened the valve .554
3rd 8.500 this opened the valve .550

 

PS lobe lift is .374 with no lash