Rocker Arm Shafts

[metro1]

I have rocker arm shafts from 2 sets of 292 heads. One has screwdriver adjusted adjustment screws with lock nuts and the other uses 7/16 wrench adjusted bolts which are hard to turn and no lock nuts. They both are in about the same condition. Will one stay adjusted better than the other?

[blucar]

From my limited experience with Y block engines, which have been with 292/312 '57/64, all of which have had the 7/16 adjusting nut like feature...
The adjuster is very tight and hard to turn, using a 3/8 drive socket with the engine running, slowly turn the socket to adjust. The feeler gauge is a special "steeped, go/no go".. I use to get mine from SNAPON,, Still have one in my tool box.
The early style with the lock nut and screw driver slot are more difficult to adjust on a running engine.
I think in the long run the nut type are less trouble..
A little info from experience on the Y Blocks... They have terrible oil passages through the heads, i found this out the hard way in the late '50's, I always used high detergent oil, 20/50 Castrol GTX.. I historically got over 100,000 miles out of an engine, had one that went over 500k on two rebuilds..

[dmsfrr]

Check the casting number on each rocker arm, there are several versions. Mixed up arms on the same shaft are possible after 60+ years.
If they are "ECG" those are the performance version.

http://ford-y-block.com/rockerarm.htm

[1930artdeco]

My 57 came with the interference nut and several of them lost their gripping power so I could turn them by hand. The nut would back itself out during a run and the valve would change gap. I swapped all of the rockers with a 56 and older version that had the lock nut. Locked them down tight and they don't change now. I just prefer the lock nut style a few more steps than just turning the nut and using a feeler gauge but they won't change on me going down the road.

[miker98038]

IIRC, all the rocker arms have the same thread. The lock nut style screws are a standard thread, the non locknut are a special machined interference fit. Age, a wire brush, or worse a tap will remove the interference fit and then they just get loose. Made that mistake years ago. I prefer the lock nut style, but I only do cold adjustments with the engine off. Plugs out so I can easily rotate the engine and my dampener is marked every 90 degrees. Even with higher lift cams and rpm’s near or over 5000 rpm, you don’t need to adjust valves that often.

Here’s an old post on valve adjustment. The first post has the Walt Knuckles method, and below is a link to several others by Ted Eaton.

http://forums.y-blocksforever.com/Topic96773.aspx

[1930artdeco]

Sponsored Links (Register now to hide all advertisements)

My valves are quiet so maybe I adjusted them to tightly. I swear I did them to 19 with my feeler gauge. I will use the Walt method to verify them at a later date. Right now I am doing floor pans.

[scicala]

I adjusted mine to .015" to make it a little quieter on my '55 272.
No problems or complaints.

Sal

[Anteek29]

Originally Posted by scicala

I adjusted mine to .015" to make it a little quieter on my '55 272.
No problems or complaints.

Sal

On my 272 I set mine to .019" so I can enjoy the rhythm of the whispering taps.

[Daves55Sedan]

Fomoco made rocker adjusting studs with locknuts for the '54 thru '56 model years. In '57, they went to a combo resistance fit stud with integral bolt head. Obviously, the '57 and later are easier to adjust on a running engine, but there is a catch.
The '57 and later adjuster stud threads wear down after a while, so they can begin backing themselves out of the rocker arm. Not good.
.015 final hot adjustment is fairly tight and may permit a small amount of compression to escape before it should on the upstroke. I would be more in favor of a looser than .019 adjustment, whereby, the valves are both closed for a longer period of time and allowing compression to build up.
I can recall many folks in the old days having them all adjusted fairly loosely like this on purpose, but they had to get used to listening to the engine "chattering" louder. OTOH, you can't make them so loose that you won't get enough intake AND possibly bend a pushrod or two either.
The factory seems to have settled on the happy medium of .019 for best performance.
As far as to which type rocker studs are better? I like the older '54 - '56 studs with locknuts, but I'm more about longevity with my repairs.

[metro1]

Looks like they both have some advantages. I think I'll go with the interference nut type as long as they are all still tight. Thanks for the replies.

[KULTULZ]

Just wondering (as he stares at a lit match) ...

Can you post the CASTING ID NOS on the individual rocker arms (according to adj type) and post them?

[5851a]

Ford has slight over sizes for the interference fit adjusters.

[KULTULZ]

This Should Help -

https://www.youtube.com/watch?v=Pst0mEdD018

[metro1]

Good information. Looks like Mummert favors the jam nut style. Thanks for your reply.

[paul2748]

These are numbers that I have based on an article in YBlock Magazine

EAN - 1.43 Lock Nut
ECG-A2 1.54 Lock Nut
ECG-B2 1.54 Interference
575XXX 1.43 Interference

There are aftermarket rocker arms with different numbers. Most, if not all, were the 1.43

Don't burn yourself with that match

Originally Posted by KULTULZ

Just wondering (as he stares at a lit match) ...
Can you post the CASTING ID NOS on the individual rocker arms (according to adj type) and post them?

[KULTULZ]

THANX Paul, but I was wondering on the rockers he has now.

[fordor41]

Originally Posted by metro1

Good information. Looks like Mummert favors the jam nut style. Thanks for your reply.

Mummerts says the type without the nut tend to wear out and loosen. I have a 292 with 105K miles showing, no telling if that's first time around, on the odometer and mine are tight as hell. I can hardly turn mine with a 3/8 " ratchet.

[KULTULZ]

Originally Posted by 5851a

Ford has slight over sizes for the interference fit adjusters.

Originally Posted by fordor41

Mummerts says the type without the nut tend to wear out and loosen

There is (was) an OS REPLACEMENT (.0023 OS) for the self locking thread.

C2AZ 6549-A

You can still find some NOS. They were still available (a few years back check) at FORD TRACTOR DEALERS.

QUALITY AFTERMARKET is available (incl roller tips). It is difficult to obtain correct lash due to rocker arm tip wear and valve stem damage. Too tight will not give enough time for the valve to cool on the seat/possible rough idle. Too loose and everything bangs together. And then there is rocker-shaft/arm wear from lack of oil.