Help. Engine rocker question. 0-320-A2B

[Mcstealth]

I am not an engine builder, but I am mechanical enough to get in trouble. 

Which of these go on the exhaust side? I ASSUME the one with the larger oil hole goes to the exhaust side but I messed up. I was not paying enough attention when I pulled these off.

 

Edited October 15, 2023 by Mcstealth

[jetdriven]

Older rockers, the oil hole on the intake rocker is toward the pushrod (the top) . The exhaust rocker oil hole is toward the valve guide (bottom). I thought those were superseded by one that has the oil hole on the bottom, for both sides.

[Mcstealth]

17 hours ago, jetdriven said:

Older rockers, the oil hole on the intake rocker is toward the pushrod (the top) . The exhaust rocker oil hole is toward the valve guide (bottom). I thought those were superseded by one that has the oil hole on the bottom, for both sides.

Thank you.

Just to be clear, the rocker on the right in the picture above, with the large visible oil orifice is Intake. The rocker on the left with the tiny hole, is exhaust?

[Andy95W]

Why not remove the valve cover from another cylinder and compare the look and numbers to the two rockers you removed?  (I suppose this wouldn’t work if you pulled all of them.)

[Mcstealth]

8 minutes ago, Andy95W said:

Why not remove the valve cover from another cylinder and compare the look and numbers to the two rockers you removed?  (I suppose this wouldn’t work if you pulled all of them.)

I caught my error on cylinder #4, as you guessed.

I did each cylinder individuallyand do not know if reassembled correctly. 

[Andy95W]

@Mcstealth- here’s a page from 2009 that is almost identical to your issue.  Hopefully it answers your question.

https://vansairforce.net/community/showthread.php?t=14475

It seems to be explained in Lycoming Service Instruction 1454:

https://www.lycoming.com/sites/default/files/attachments/Rocker%20Arm%20Assembly%20Replacement%20Part.pdf

Basically, it seems to say that the rocker with the oil drain on the valve side is for the exhaust and the one with the oil drain on the pushrod side is the intake.  (BTW- this corresponds to what Byron- @jetdriven posted above).

But please double check!

 

Edited October 16, 2023 by Andy95W

[EricJ]

1 hour ago, Andy95W said:

Basically, it seems to say that the rocker with the oil drain on the valve side is for the exhaust and the one with the oil drain on the pushrod side is the intake.  (BTW- this corresponds to what Byron- @jetdriven posted above).

But please double check!

That's my recollection as well, that draining the oil on the valve side helps to cool the exhaust valve.   The intake valve doesn't need it.

[Mcstealth]

2 hours ago, Andy95W said:

@Mcstealth- here’s a page from 2009 that is almost identical to your issue.  Hopefully it answers your question.

https://vansairforce.net/community/showthread.php?t=14475

It seems to be explained in Lycoming Service Instruction 1454:

https://www.lycoming.com/sites/default/files/attachments/Rocker%20Arm%20Assembly%20Replacement%20Part.pdf

Basically, it seems to say that the rocker with the oil drain on the valve side is for the exhaust and the one with the oil drain on the pushrod side is the intake.  (BTW- this corresponds to what Byron- @jetdriven posted above).

But please double check!

 

Thanks Andy. That response was above and beyond. Appreciate it.