A Broken Valve Shim and It's Aftermath

[Guest]

Hi everyone,
I finally finished my valve adjustment (after some problems sourcing shims), and was obviously very excited to see what a difference it made. Started the bike up, and immediately there was a pretty serious knock coming from the Cyl. 4 side. (i already had a JB weld patch on a small 1 1/2" crack in the valve cover over #4 intake that i assume was from previously being improperly torqued). Erring on the side of caution, i shut it down and did a little research, and came back with a few possibilities. I couldn't hear the knock while just cranking so i had to start it again, and heard the knock immediately. I poked around a little with my ear pressed up against a screwdriver, and while i was doing that, the knock stopped, the motor began to run much, much worse, and, of course, oil poured from where my previously JB Welded crack had continued across that leg of the valve cover, which is now in three pieces. So i removed the valve cover, and saw: A) Lack of shim, B) Split valve cover gasket, C) "Slice" in the cylinder head right under the valve cover gasket split, and finally, D) A mangled Cyl. 4 intake cam. Pictures to follow. It turned out that the shim wasn't actually missing, but had totally shattered into a whole bunch of tiny pieces, which gouged up the cam, shot through the head and valve cover gasket and cracked the valve cover the rest of the way, got stuck on-end in between the camshaft and the head (next to the bucket) and also left a nice little pock between the bucket and the wall of the head.

So now come the questions.
-What do you think could have caused this? I know it was not a seating issue as i made damn sure they were all seated properly. I want to be sure this doesn't happen again
-What could be salvaged? I'm thinking the head will be fine with a spot of TIG welding and grinding/sanding to fill that hole where it shot through (more JB Weld would be a bad idea, right?), new valve cover (obviously, already ordered because of the pre-existing crack), new gasket, and new shim (also obviously). What I'm a little more unsure about is the camshaft. It looks pretty nasty, and i'm pretty sure i already know the answer to that one.

As always, thanks in advance. You guys rock.

More photos to come. sorry i am seriously struggling with them.

[jrobert94]

http://s723.photobucket.com/user/Joe_Robert/library/Cracked%20Shim

Alright i think this one will work

[Nessism]

Post the [img] link in your post and the photo will show up.

Shim obviously got spit out. Most likely it wasn't seated in the bucket before you started the engine. Sorry for the loss.

[Nessism]

[jrobert94]

Thanks, i appreciate that.

[TeamDar]

The cam cap/bearing does not appear to be seated against the head. Could have been the cause or could have been the result.

[JTGS850GL]

Cam is shot as is the valve cover. Replace both and I'd replace the shim bucket as well. The trick is going to get all the debris out. get a strong magnet pickup tool and see if you can pick up most of the metal pieces. No chance of assembling the busted shim to make sure that you have it all, so the plan now is the get what you can out and flush everything into the oil pan. Once you've done that you need to pull the pan and clean it out. Replace the oil filter and flush that area out as well along with the oil screen. At least that's my suggestion.

[JTGS850GL]

The cam cap/bearing does not appear to be seated against the head. Could have been the cause or could have been the result.

Good catch.

[jrobert94]

The cam cap/bearing does not appear to be seated against the head. Could have been the cause or could have been the result.

No sir, i had to loosen that a bit to get a chunk out that was wedged in there. it was good and tight beforehand.

Cam is shot as is the valve cover. Replace both and I'd replace the shim bucket as well. The trick is going to get all the debris out. get a strong magnet pickup tool and see if you can pick up most of the metal pieces. No chance of assembling the busted shim to make sure that you have it all, so the plan now is the get what you can out and flush everything into the oil pan. Once you've done that you need to pull the pan and clean it out. Replace the oil filter and flush that area out as well along with the oil screen. At least that's my suggestion.

that's what i thought (i knew the cover was though, haha) i got a lot of the debris already but i'll get in there with a magnet while the cam is out. Would aerosol degreaser be a good bet for flushing the rest out? Also what are your thoughts on having that divot welded?

[Sandy]

There could have been a small piece of debris or grit under the shim causing it to not lie totally flat in the bucket. Just a guess.

[JTGS850GL]

Don't worry about the divot. As long as the new bucket moves freely then the head should be OK. You can use a variety of aerosol spray cleaners or even simple kerosene to flush out everything.

[Steve]

Now, I would like to address the cause, if I may.

Were you using the "official" bucket-depressing tool to change your shims?

If so, did it ever slip off the side, allowing the shim to slam up to the cam?

Any chance the shim was not fully seated when it slamed up?

Even simply slamming against the cam can crack the shim. Running the engine just spit out the pieces.

I was a bit luckier with mine. The shim was not fully seated when the tool slipped off the bucket.




That is why I use the "zip-tie method" for holding the valve open.

.

[jrobert94]

Don't worry about the divot. As long as the new bucket moves freely then the head should be OK. You can use a variety of aerosol spray cleaners or even simple kerosene to flush out everything.

There is actually a hole through the wall of the head right beneath there the gasket/cover would sit, directly toward the spark plug from the bucket. you can see it clearly in this one.

Sorry if my wording was unclear. But good to know that ding you're talking about won't be a problem.

Now, I would like to address the cause, if I may.

Were you using the "official" bucket-depressing tool to change your shims?

If so, did it ever slip off the side, allowing the shim to slam up to the cam?

Any chance the shim was not fully seated when it slamed up?

Even simply slamming against the cam can crack the shim. Running the engine just spit out the pieces.

I was a bit luckier with mine. The shim was not fully seated when the tool slipped off the bucket.




That is why I use the "zip-tie method" for holding the valve open.

Yes i was using the "official" tool. i thought that, being official and all, it would be the best tool for the job. how naive of me. i hadn't been aware of the zip-tie method. It's funny you mention how easy they apparently are to crack, i was thinking while working with them how brittle they must be if they're hard enough to stand up to all that rubbing on the cams. the tool may have slipped, i'm not really sure. i know it did a couple times throughout the process but i'm not sure exactly on which ones. i'll check them all to make sure no other ones are broken and waiting to wreak havoc at a later date

[Brendan W]

Was it an original Suzuki shim? I have used some aftermarket shims with no chamfer and one was a bit tricky to seat in the bucket.

[jrobert94]

Was it an original Suzuki shim? I have used some aftermarket shims with no chamfer and one was a bit tricky to seat in the bucket.

i don't know. it was from Z1, i believe it was made by K&L, and it definitely had a chamfer around the edge