Somehow our turbo engine has three ECG 6564 B2 rockers and 13 5751066 rockers in it! Mummert's sites state that ECG 6564 is a 1.54:1 rocker, but says nothing about B2 marking. 5751066 is definetely a 1.43:1 rocker. Houston, do we have a problem? Or is those B2 rockers some replacement ones for 5751066 units?
Ok, I found one Walt Nuckels article about setting the valve lashes, but that didn't make me sure .
http://www.hydratech.com/pctc/Public_Documents/waltnuckels-valvelash.pdf

 Seppo from Järvenpää, Finland
www.hollowheads.net (just click the hole in the head to proceed)

I’m surprised no one else chimed in on this one but considering how vague the information is on how to identify the rocker arms, I probably shouldn’t be surprised.  But the B2 suffix typically works in identifying the larger ratio (1.54) rockers but I seem to find exceptions even to this.

 

The easiest way I’ve found in identifying if a rocker is 1.43 or 1.54 is the drill bit test.  If the shank of a 5/16” drill bit fits between the body and thr adjuster ball, then the rocker is a 1.43:1 but for the 1.54:1 rockers, it will take a smaller ¼” drill bit shank to fit between the body and the adjuster ball.  But after checking the actual ratios of a bunch of stock rockers, there is a considerable amount of variance in the rocker ratios as delivered from the factory.

 

If blueprinting the rocker arm assemblies, then it would be suggested to take a large number of rockers to check for the actual ratio in which to get sixteen that are similar in ratios with the adjuster screws all being at the same location or position in the rocker.  How deep the adjuster screw is screwed into the threads also affects the rocker ratio so that is a player also.  If the screws are varying in height througout the assembly, then the rocker ratio is likely varying accordingly.

Lorena, Texas (South of Waco)

Thank's Ted! Now I'll rush back to garage and lay down all my drills and do some identifying exercise. How about B1 suffix?

 Seppo from Järvenpää, Finland
www.hollowheads.net (just click the hole in the head to proceed)

Ok. This may explain a littele about our engine idling not so smooth as we would like to .

We have one ECG in number 5 cylinder intake side and two others at the exhaust side at numbers 7 and was it at number 4. S#it!!! More work, but that's life

 Seppo from Järvenpää, Finland
www.hollowheads.net (just click the hole in the head to proceed)

Yes, we have been led to believe ECG 6564-A2 rockers were all 1.54 ratio. Usually they are, but as Ted points out & also John Mummert in an article in issue # 83 of YBM, a few aren't. According to John, another way to confirm the difference on the similarly marked rockers, is to note that the 1.54 s have a small 3 digit number near the adjusting screw. The 1.43 impostors have a single digit number. Just another nuance to try and remember..

Paul

I had the same problem with my old 292 and had checked everything but could never get timing just right, engine always pinking, and checking valve lashs, timing, dwell, etc nothing made it better or worse. Then by mistake noticed the rocker arm adjusters were different sizes which made me curious, end result I had a complete set of High ratios on one bank and a complete set of 5751066 on the other..... Put another High ratio on and hey presto nice idle, adjust timing and she was away.... Always the little details that cause trouble.

1957 ________________ Ford

\___((_______________))___/

(@)________V__________(@)

[________I_____I_________]

__[__]__ o_______o___[__]___



Y Blocks, The New Flathead!

Paul.  That’s a good tidbit of info regarding the 3 digit code at the adjuster end of the rocker. Thanks.

 

The B1 suffix on the rocker arms is not a sure indicator but points to most being the 1.54 ratio but I’ve found that most B1’s have a slotted adjustment screw with a locking nut.  The exception is I’ve seen a limited number of B1’s that measure as low as 1.2:1 rocker ratio and I have to assume this was just from sloppy machining.  Although the drill bit test is good in that it’s fast, unfortunately it doesn’t nail down the actual ratio as some rockers actually measure out in excess of 1.7:1 while others fall in the 1.2:1 category.  And there’s those 1.43:1 rockers that actually measure out to being 1.5:1 while there are 1.54:1 rockers coming in at quite a bit less than advertised.  There’s lots of tuning and blueprint opportunities lying in the rocker arms for sure.

Lorena, Texas (South of Waco)

Just curious,I have a set of EAN 6564 B1 and a set that have only 76 on them.What are these off of?

 

Paul,

Boonville,MO

Ted: It appears now, just to complicate things further, anyone building a serious Y-block, needs to check every Rocker Arm to ensure that they have a properly matched set, regardless of the desired ratio. So, while expensive, about $350, there are new forged rockers assemblies now available, & sold by John Mummert. I don't know who manufactures them, but has anyone checked them out for accuracy?

Paul

Could be from here...
http://www.rockerarms.com/F11%20Roller%20RA.jpg

www.rockerarms.com


 Seppo from Järvenpää, Finland
www.hollowheads.net (just click the hole in the head to proceed)