Broken rocker arm

[tab a]

1972 350 with lots of miles that burns lots of gas, and oil. Oil pressure is decent when moving, but pretty low at idle. Recently developed a knock that goes away when the 2nd spark plug wire on the right, is shorted. Pulled the valve cover and found the base of the 4th rocker arm broken. Pushrod looks straight. Same noise with the broken arm removed.

1. I'm thinking I need to pull the pan and look at that rod/journal?

2. Can the pan be pulled with everything else in place? Auto tranny.

3. Is a broken arm typically of symptom of ??????, or just old age?

4. Is it possible to buy a single rocker arm, to replace the broken one?

Thanks!

[ckhd]

1) I wouldn't yet
2) I think you have to at least lift the engine some to get the pan to clear
3) They fatigue after a while
4) I'm pretty sure you can get just one. If one has fatigued, good chance others are getting there.

The reason I answered that way on 1 is that the fourth one back means that the "second from the front" isn't working. Replace the rocker, then decide if you still want to pull the pan. A rocker replacement is cheap and easy, while pulling the pan is a pain in the butt.

[ckhd]

Oh, change the oil if you're not going to pull the pan. There may be some metal fragments floating around in there.

[st1x10]

Single rockers can be bought. I would replace and then change the oil like above. It might be ok and then if you find a problem you only replaced a rocker that you were going to have to replace anyways. So no wasted money.

[72armyswbtruck]

To pull the tranny pan on our trucks depends on wether or not the transmission cross member was bolted on or riveted on. If it was bolted on then you can with some work unbolt the crossmember and then remove the tranny pan, I would at the very least drain the oil replace the pick up and clean out the screen. Good Luck