Lost a tappet

[OBSteve]

Recently I've noticed a decrease in power - 50% to be precise. Investigation showed that my left cylinder intake tappet retaining screw came loose and allowed the tappet screw to unscrew and begin hitting the aluminum access port util it punched a hole through it and subsequently disappeared. Without the valve actuation I've obviously lost the power of one of my cylinders. I've felt around the valve spring area and visually inspected it as much as possible but can't locate the tappet screw or retaining nut. I've probably put 50 miles on the engine in this condition before I figured it out. Questions are: do we think this damaged the engine in any way? Where (if still inside the engine) would one expect to find the missing pieces? (oil spinner?). Other thoughts?

[deuce_7]

The bits & pieces from the lost tappet adjusting screw and nut could have taken the path of returning oil from the cam case and fallen harmlessly to the bottom of the engine. They will stay there until the engine is disassembled next.

What I'd do:
- Drain the crankcase oil; look for swarf and small flakes/chips.
- Disassemble and check the oil filter slinger for signs of swarf and small chips. If no swarf or chips present, it's a good outcome.
- Clean, reassemble, fill with fresh oil.

The tappet screw threads in the rocker arm could be damaged from the hammering action on the valve cover cap. You'll know either way when attempting to install a new tappet adjusting screw and nut. If damaged, cylinder head disassembly would likely be necessary to repair/replace the rocker arm.

[OBSteve]

Thanks for the reply. I did just as you mentioned and, luckily, did not find any debris in the oil or slinger. It'll be a mystery as to where the tappet made its way to until engine disassembly but I'm intrigued by the hole in the valve cover that looks as if it were drilled and tapped. I wonder if it hammered it's way out of the engine?

[deuce_7]

... I wonder if it hammered it's way out of the engine?

That would also be a good outcome; i.e., no stray pieces inside the engine.

Hope you can acquire a tappet adjusting screw that has no problem threading back into rocker arm.

[Michael Stoic]

Steve, ...please post some pictures. It would be interesting to see what you are describing.

--
Michael

[OBSteve]

Not my finest work:


By the way it took me 30 min to figure out how to post this picture (and I work in IT).
I created an account on flickr, tried all the default image sharing options (none worked), then searched the web for 15 min before I found this post:
https://stiobhart.net/2018-01-12-flickr-image-hosting/
Very convoluted. Should be a simpler way. Love to hear it if you have one...
Steve

[hillyhonda]

Hi Steve - for my pic in 'Everything else' I used https://imageresizer.com/ if that helps.
Cheers, Pete