I was doing my first valve clearance job today and did something stupid. I pulled the shims from an intake and exhaust valve that were too tight to check their values, and then proceeded to turn the engine to check the other exhaust valve WITHOUT putting the shims back in. I felt something scraping when doing this. I turned the engine the rest of the way forward and immediately replaced the shims. The two cam lobes are scraped along the edges where I'm guessing they hit the buckets and slightly rough to the touch.

So the question is: how much damage have I done here? The scrapes are pretty small. After putting the shims back it, the engine seemed to turn fine.

Thanks for the help.

I doubt you did anything serious. Make sure you thoroughly clean the buckets to get as much metal scraping out as you can. The cam lobes would have scraped along their edges (around the rim of the bucket, as you mentioned) so the faces will be ok. If it was run under engine power or turned over 100 times by hand you might have caused some serious wear damage, one or two slow turns wont be bad.

I would give the scratched parts a lick with very fine wet and dry paper, just enough to remove the high spots.

Only other option I see is to replace the scratched parts 

Pictures of the two damaged lobes are attached. I might try some very fine sandpaper. Replacing the cams is definitely beyond my mechanical abilities.

How would I go about cleaning the buckets? The clearance is a little too tight to get in there, so compressed air to try and blow everything out?

Thanks for the help. This forum is amazing.

Removing / replacing the cams isn't too bad. It's scary undoing and tightening the journal caps but if you do them gently and each one a bit at a time to even it out you'll be ok. If you got as far as pulling the valve cover and shims then the cams are a very small step in comparison

But those scrapes? I wouldn't worry, maybe do as Sledge suggests and tidy the edges but they don't looked wrecked by a long way. These things spin round at thousands of RPM accuating (smashing into?) the buckets, a bit of lost material on the very edges isn't going to seriously impede it working or they'd explode when you pressed start.

Cleaning wise, I'd pull the shim and just make sure any shavings are removed. There isn't a lot of to do. The oil filter *should* pick up any loose bits.

Quote from: nit on May 13, 2018, 12:00:44 PM
. I might try some very fine sandpaper.

Don't use sandpaper. Grit will find its way into the internals. Use a very fine wet and dry paper and lube it with oil. It will only take a few passes to remove the highspots , wipe everything clean afterwards.

not trying to be funny but iv had bikes running reliably with cam lobes that looked alot more beat up than that, i wouldnt worry about it

I second that, my 89 had a crows foot like scratch in 1 cam and in 40K it never changed much at all. Maybe got a wee bit fainter.
I'd not worry about it.
Cool.
Buddha.