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My 360 has a tapping issue. You can kind of hear it in the attached video and the tapping is coming from the left bank, mostly I think from cylinder 5. I took the rocker cover off and found a couple of rockers that are off center from the valve springs. They are still fully covering them, just off center. Is this acceptable and/or could this be causing the tapping? I have some pictures of that as well. If that is not it, what is the best way to go about trying to diagnose the issue? I should add that when I got the truck I did a compression test and #5 came back with the lowest compression at the time, although still an acceptable level (but noticeably low even for a cold and dry test). I am still learning my way through this engine so as much help as can be provided is much appreciated.
Sorry for the poor audio quality, I had to convert it to a different format to upload. I can post a link to a higher quality one if it helps. This is the first rocker at the front of the engine.
The offset on a few rockers is normal but you may need to remove the shafts to check for wear. The rockers should be flat across the tip and not show any impression of the valve tip. Also check the pushrods for wear.
If you remove the shafts, make sure you put the bolts back in the same holes. Some years have a necked down bolt for oil flow so be sure that one goes back in the right position.
The offset on a few rockers is normal but you may need to remove the shafts to check for wear. The rockers should be flat across the tip and not show any impression of the valve tip. Also check the pushrods for wear.
If you remove the shafts, make sure you put the bolts back in the same holes. Some years have a necked down bolt for oil flow so be sure that one goes back in the right position.
Thank you for that. They do all look flat across the tips at least, but I will do a closer inspection. I was planning on manually rotating the engine also to see how they are operating.
Also look at your manifolds. A small exhaust leak will sound like a tap as well. The inside of your engine looks pretty clean. Does the engine run well and smooth? Maybe run another compression test too?
The engine does run fairly smooth once it's warmed up, but I'm sure some of that is just needing some fine tuning of the carb and timing and such which I haven't done yet. I haven't seen any issues around the manifolds, but that doesn't mean they aren't leaking since I'm sure they haven't been touched since installed. After the truck is warm, I have seen some small clouds of smoke around that same area of the cover, but the rocker cover seals weren't looking to great anyway.
When checking the rocker arms for wear, is there anything I should be looking for that would indicate wear? And is there anything that would show wear without even removing them, basically anything obvious that I may see?
You have to remove them to see the wear. The way the system works is that the Rocker wears the bottom of the Shaft and the only way to see the area is to remove the Shaft and Rockers.
When checking the pushrods make sure they go back in their same respective hole. The ball on the pushrod and the lifter wear together. Making their own pattern.
Engine Tapping Noise
