Noisy rocker arm?

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SWAP ROCKER ASSYS SIDE TO SIDE...SEE IF IT CHANGES IT... SIMPLE AND QUICK TO DO GOOD LUCK
 
When I worked at a Ford dealer in the late 70s the 351c400m engines had issues with valve guides being sloppy. These were New engines still under warranty. Sounded like a bad lifter or rocker. Any thing done to your heads along that line like guides?
 
Took the valve cover off again and started it up. Pushed down hard on each rocker arm on the pushrod side and they all felt the same, the noise never changed. I know the oil pressure is good, because it was spraying the hood!
The lifters don’t have any “squish” to them after running.
Craig, do you have access to a mechanic's stethoscope? You could pick up on an exhaust leak really quick with that and isolate it.
 
When I worked at a Ford dealer in the late 70s the 351c400m engines had issues with valve guides being sloppy. These were New engines still under warranty. Sounded like a bad lifter or rocker. Any thing done to your heads along that line like guides?
Yes, the heads were rebuilt by a machine shop. They were pretty rusted out, so they needed all new valve guides and seats.
 
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Craig, do you have access to a mechanic's stethoscope? You could pick up on an exhaust leak really quick with that and isolate it.
I’ve used those before, but don’t have any. I ordered some nice gaskets and some copper gasket maker. So if that doesn’t make the noise go away, I’ll try to find some I can use.
 
I’ve used those before, but don’t have any. I ordered some nice gaskets and some copper gasket maker. So if that doesn’t make the noise go away, I’ll try to find some I can use.
Exhaust leaks at the head and valve train noises can be really deceiving to diagnose. If we were in a better place, I'd ride over and give you a little help.
 
Well it’s not an exhaust leak :(
How much side to side movement should the stamped rocker arms have when not under load?
 
Pulled the lifters out and they all look and feel perfect. From what I can see through the lifter bores, the cam looks great too.
 
I swapped the rocker assemblies from side to side. At first it was distinctly louder on the passenger side. Now it’s just barely louder on the driver side. I’m thinking about pulling an assembly off of my perfectly good running and driving Duster to see if it goes away then. I just hate to open that can of worms.
 
Craig, are you certain the rocker shafts and rockers are installed correctly? There is only one correct way.
 
The oiling holes in the shaft face down, right? That’s what the wear marks on them show.
Yes, but it's more specific than that. If there are slots in the ends of the shaft, the passenger's side slot orients down and to the rear. The driver's side shaft slot orients down and to the front.

Some do not have slots, so you position the oiling holes so they point down and towards the valve springs...in other words, oil holes down and pointing to the exhaust (outside) of the heads.

The rockers themselves are also specific in their installation. They are stamped "L" and "R". That does not mean left and right side of the engine. That means as standing on the side of the car looking at the rocker assembly that each pair of rockers the one on the left has the "L" and the one on the right has the "R". The pushrod cups offset to the inside of each pair like in this picture.
BIG BLOCK ROCKER ORIENTATION.png
 
Yes, but it's more specific than that. If there are slots in the ends of the shaft, the passenger's side slot orients down and to the rear. The driver's side shaft slot orients down and to the front.

Some do not have slots, so you position the oiling holes so they point down and towards the valve springs...in other words, oil holes down and pointing to the exhaust (outside) of the heads.

The rockers themselves are also specific in their installation. They are stamped "L" and "R". That does not mean left and right side of the engine. That means as standing on the side of the car looking at the rocker assembly that each pair of rockers the one on the left has the "L" and the one on the right has the "R". The pushrod cups offset to the inside of each pair like in this picture.
View attachment 1715917104
Pretty sure mine aren’t slotted. Sounds like I have them installed correctly. I’ll double check tomorrow though
 
Checked the installation direction of both rocker arm assemblies and they’re good.
I pulled an assembly off of my Duster and bolted it on, NO MORE NOISE!
I’m so relieved.
Thanks to everyone for all of the input. Going to just order a whole assembly from 440source now!
 
My comment is about the drawing in post #42. Which I believe is correct.

The oil holes in the shafts can be anywhere you want to put them because eventually the rockers will get oil. By having the holes at the bottom of the shafts, or very close to the bottom as in the drawing, the rockers will get oil as soon as possible.
 
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