|
By Hollow Head - 16 Years Ago
|
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
|
|
By Ted - 16 Years Ago
|
|
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.
|
|
By Hollow Head - 16 Years Ago
|
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?
|
|
By Hollow Head - 16 Years Ago
|
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 
|
|
By PF Arcand - 16 Years Ago
|
|
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..
|
|
By 2DRHRDTP57 - 16 Years Ago
|
|
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.
|
|
By Ted - 16 Years Ago
|
|
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.
|
|
By PWH42 - 16 Years Ago
|
|
Just curious,I have a set of EAN 6564 B1 and a set that have only 76 on them.What are these off of?
|
|
By PF Arcand - 16 Years Ago
|
|
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?
|
|
By Hollow Head - 16 Years Ago
|
Could be from here...
http://www.rockerarms.com/F11%20Roller%20RA.jpg
www.rockerarms.com
|
|
By DANIEL TINDER - 16 Years Ago
|
I bought a set of B2 forged repro rockers off eBay (MadDog) 3 yrs. ago. They seemed well made, so I neglected to measure them for ratio uniformity. They came with jamb nuts which I did not use initially, as the friction hex adjusters seemed tight enough. Down the road though, when a lash check showed some variation, I decided to install the nuts. That's when I discovered one would not fit! The hex adjusters were apparently oversize, but the odd nut had OEM thread ID. I contacted MadDog, but no cooperation. Another eBay seller (Falcon) was offering the same rocker set (I thought), so after contacting/explaining, he had his distributor send me a free replacement nut (and adjuster). Strangely, the new adjuster was NOT oversized thread, but it's nut fit my MadDog adjuster.
This makes me wonder how many manufacturers are turning these repros out? You wouldn't think the market would support more than one. I e-mailed Falcon/distributor to try and discover the story, but they must have thought they had done enough, as I got no reply. If the latest repro version has smaller adjuster thread, I wonder if there is still a friction fit in the latest rockers (?), which if not, would of course make the jamb nuts mandatory.
|
|
By PF Arcand - 16 Years Ago
|
|
Seppo: Those are the other after market (aluminum) Rockers available. I believe they are manufactured by Dove. I don't know anything about what quality they are. The ones I was referring to are Forged Steel, 1.54 ratio, copies of the originals. They are sold by John Mummert & possibly elsewhere.
|
|
By Y block Billy - 16 Years Ago
|
|
another way to check is to take a caliper and measure the distance from the shaft bore of the arm to the rocker ball. I cannot remember the dimensions and I am on the road at the moment so do not have any in front of me for reference but the lower the distance from the arm to the ball, the higher the ratio. one thing to remember, when you shorten the distance from ball to pivot point (shaft center) you increase the force needed for the lifter to compress the spring, so the higher the ratio, the better oil you should have to protect cam and lifters because it will be harder on them.
|
|
By PF Arcand - 16 Years Ago
|
|
Returning to this subject. Re john Mummert's observations on the Rockers, re the 3 digit number on the adjuster end of the 1.54s. I should have noted that he only referred to the ECG6564-A2 rockers. He made no reference to the suffix "B2" rockers. So they could be another ??.. Now, looking at Charlie from Florida's question & photos of "today", I see that one of the rockers in the photo is a B2, and has a 2 digit number on the adjuster end. So, it appears we have yet another ??. This is getting really confusing...
|
|
By webconst - 16 Years Ago
|
|
Thank you to all who responded. Paul and Billy followed your instructions, they do have numbers on the adjusting end and 5/16" drill shank will not fit. Can I assume these to be 1:54:1?Thank you, Charlie, Central Fl. 
|
|
By PF Arcand - 16 Years Ago
|
|
Probably, but not guaranteed. Check each one carefully for variations. Also, you have the interference type adjusters (no jamb nut) so check to see that each one is snug when turning it. If any ones are obviously loose, you could have problems with not holding it's setting. Oversize thread adjusters used to be available, but I'm not sure of a current source. Maybe someone else can help there.
|
|
By Unibodyguy - 16 Years Ago
|
|
I can recall that Lindsy Shoemaker from Austrailia several years ago had a very simple way of identifing "big" and "small" roccker assemblys by measuring the length of the rocker itself. Can't recall for sure but it seems as thought the 1:54's were 3 in. in length and the 1:43's were I think a 1/4 in. shorter?? Can't recall. It was in YBM. Michael
|