Can different rocker arms work together

C

cjc56

Senior Member
I just torn down a 56 312. I found that one head had rocker arms stamped EAN 6564 B1 and the other head had rockers arms stamped ECG 6564 B2. Both heads were stamped ECZ B. Is it okay to have these two different sets of rocker arms as long as all the rocker arms are on the same head? If it is okay will I see any difference between the performance of the heads?
 
The EAN's are 1.43 ratio,the ECG's are Hi-lift 1.54 ratio. So look at it this way,if your cam lift is .320 times the rocker arm ratio gross lift is now .451 & .492,You should try and get another set of ECG's. It's been years since I messed with y-blocks but maybe some one could chime in on this,if you could put the higher ratio 1.54's on the exhaust valves and leave the lower lift on the intakes that would help exhaust flow.
 
cjc56 said:
I just torn down a 56 312. I found that one head had rocker arms stamped EAN 6564 B1 and the other head had rockers arms stamped ECG 6564 B2. Both heads were stamped ECZ B. Is it okay to have these two different sets of rocker arms as long as all the rocker arms are on the same head? If it is okay will I see any difference between the performance of the heads?
Click to expand...
Ford made all(?) the 55 & up y-block heads with the same sized exhaust valves but they increased (only) the Intake valve size in their 'performance' heads.

IMHO if you can't find more ECG rocker arms to make up a set, and following Ford's prior intake valve logic.... put the 1.5's on the intake valves and the 1.4's on the exhaust valves. This will balance out the side-to-side difference and give the slight performance increase to all cylinders equally.

I had the same situation with my '55 until one of the guys in our club give me some of his extras. Is it possible your T-Bird and mine were put together (badly) by the same folks? haha :o
.
 
Last edited:
I do have a complete set of 5751066 rockers. Would those work on my 56? If so what kind of performance will I get?
 
I think I will try your suggestion and used the ECG on the intakes and the EAN on the Exhaust. I will save my set of 5751066 for a later project. Will the adjustment remain the same on all the valves, even though I am using different rocker arms.
 
After you disassemble them to swap the rockers around on the shafts make sure the oil passages in the; heads, stands & shafts line up correctly before re-installing.

Yes, you can use the same valve clearance all around.
.018-.019 hot, for a stock cam. If you set them at .018 they may(?) click a bit less.
 
cjc56 said:
I think I will try your suggestion and used the ECG on the intakes and the EAN on the Exhaust. I will save my set of 5751066 for a later project. Will the adjustment remain the same on all the valves, even though I am using different rocker arms.
Click to expand...
Look at this example of a Ford SBF cam:http://www.summitracing.com/parts/lun-10310100lk/overview/ This is a copy of the Ford Motorsports cam for SBF's, both Y-blocks and SBF's suffer from poor exhaust flow this is why you will notice in the specs that the exhaust duration and lift is increased, by installing the higher lift rockers on the exhaust you will get a similar effect. ;)
 
So it seems that we have a disagreement on where to use the higher ratio rockers. Before I assemble the rockers, does anyone else have a opinion on whether the higher ratio rockers should be put in the exhaust or intake valves?
 
cjc56 said:
So it seems that we have a disagreement on where to use the higher ratio rockers. Before I assemble the rockers, does anyone else have a opinion on whether the higher ratio rockers should be put in the exhaust or intake valves?
Click to expand...
Also you can pick up some good tips here:http://webrodder.com/article/y-block-ford-head-valvetrain-accessory-drive Might want to grab a copy of this: http://www.amazon.com/Ford-Y-Block-Engines-Rebuild-Workbench/dp/1613250614?tag=atomicindus08-20
 
Last edited:
I agree with Jeff.

Barker highlifts for the 223 inline6 say to use on the exhaust only. Nothing about the intakes. I know this is sort of apples and oranges (6 vs 8 heads).
 
Just for discussion. A combustion engine is essential an air pump. Adding more air into the cyclinder is nice but it needs to exit.

Your best to find another set but in this situation your better off with the b rockers arms on the exhaust.

Your vacuum may increase some too.
 
I'll still vote for putting them on the intakes, cuz Ford put bigger intake valves in their ECZ-G / EDB-D performance & supercharged heads but left the exhaust valves the same. ;)
 
Noted. But your forcing air in with a super charger. Wouldn't it be also benifitional to increase the exhaust as well then?
 
Granted if you have poor compression, the amount of advantage in the discussion at hand maybe debatable too.
 
Tinker said:
Noted. But your forcing air in with a super charger. Wouldn't it be also benifitional to increase the exhaust as well then?
Click to expand...
Yes the supercharged example is a bit over the top here, but Ford didn't seem to think the exhaust valves needed to be bigger, and they left the exhaust the same size on their dual quad engines also.

My initial suggestion (in comment #3 above) was to help cjc56 make up for having to use his substitute ECZ-B heads because the two ECZ-G (big intake valve) heads he thought he had, was actually only one.
And, I think he's going thru the engine so poor compression hopefully won't be a problem.

http://www.fordbarn.com/forum/showthread.php?t=151638&highlight=cjc56
 
Last edited:
You have 14.7 psi give or take pushing air through the intake valves, except for supercharged/turbocharged engines. You have lot more pressure pushing the exhaust out so the engineers use more of the available area for the intake valve. Also, some of the intake charge turns to heat so there is less volume of exhaust gas to be expelled than fuel/air charge to be drawn in. I vote for putting the higher ratio rockers on the intakes.
 
I have no doubt your intention. I'm just enjoying a conversion.

Ford as great as they were, maybe it was not perfect. A lot of their decisions were based on retooling. Dare I say. Reason for After market heads/intakes, porting, dual exhaust, stroker kits...

To add. Valve size vs duration is different. If all the rockers were the same, and you are supercharged, then a little larger valve would be an advantage. But if the duration of the intake valve opening was half that of the exhaust then it wouldn't matter how big the intake valve was.




.
 
Last edited:
Dobie Gillis said:
You have 14.7 psi give or take pushing air through the intake valves, except for supercharged/turbocharged engines. You have lot more pressure pushing the exhaust out so the engineers use more of the available area for the intake valve. Also, some of the intake charge turns to heat so there is less volume of exhaust gas to be expelled than fuel/air charge to be drawn in. I vote for putting the higher ratio rockers on the intakes.
Click to expand...

Doesn't air expand under heat though... I mean doesn't something force the piston down.
 
Last edited:
You must log in or register to reply here.
Back
Top