Now what to do?

[pelky350]

After replacing my valve cover yesterday I noticed I I have found my probable ticking noise, exhaust valve on driverside has some tar like residue on the inside of its spring possible meaning failing valve guide. It's also right under my old CD-R location so I haven't ruled out it being sludge coming from it and landing on the warm exhaust valve maybe? It's right where I thought my tick was coming from though but has since quited a fair amount since I flushed with trans fluid and will be using marvel to continue cleaning next few oil changes. Question is estimated how long does this thing have before something catatrphic happens? It's not very bad yet looks like it's just beginning to happen but noticibly dirtier than the other valves inside the springs.

 

[IDIBRONCO]

From my observations in the past, what you see when an exhaust valve guide starts to go looks kind of "dry" and "powdery", not like sludge. Since I haven't seen what you've seen, I'm not going to give an opinion on what it looks like. I don't think that a bad valve guide will make a ticking noise, but the chuffing noise won't be as pronounced at the tail pipe with a turbo. Since you only have this stuff on the inside of your valve spring, I'm going to lean toward it not being a valve guide issue. the residue from a bad guide will be all over your valve spring, rocker arm, top of the push rod, and the under side of the valve cover. remember, when combustion gasses leak a valve guide, they are under a lot of pressure, both from the combustion itself and from the compression of the piston. if this is a valve guide going bad, I think it's in the early stages at this point. How long before catastrophic engine damage occurs if it is a bad valve guide? That's almost like asking how many Big Macs can I eat before I have a heart attack? It's hard to say. I guess it kind of depends on how much and how hard you use your truck. My advice would be to run it for now while keeping a close eye on the sound. If you notice it getting worse or a miss starting to occur, then it would probably be time to dig deeper. As much of a PITA as it would be, maybe you could pull the valve cover every 4 to 6 weeks or so to check on the condition of the residue on your valve.

 

[Macrobb]

Well, I drove around for a while with an evidently worn guide without issue... When I found it, the guide had 1/16" of play side to side and the leaked gasses had discolored the underside of the valve cover in that spot(so at least 300F). Note that that guide wear was due to the valve constantly beating it's way into the piston, too, so I'm sure it wouldn't wear like that normally.
That made a definite chuffing sound there...

Usually what happens with guide wear is that the stock seals(on 7.3s) don't provide enough lubrication, the guides wear until enough gasses come up and melt the seal away such that oil finally does lubricate it again... at which point it stops wearing but might use more oil.

 

[pelky350]

Sounds like I'm just gonna run it for a while and see what happens, I just heard stories of valves and pistons meeting and dropping valves and such but it sounds like I'm a ways from that at least for now

 

[Macrobb]

Sounds like I'm just gonna run it for a while and see what happens, I just heard stories of valves and pistons meeting and dropping valves and such but it sounds like I'm a ways from that at least for now

Valves are going to hit the piston only with bad clearances(from a poorly done rebuild/valve job) or a lifter that 'pumps up'; pretty rare.
it takes a lot to drop a valve; I don't expect it to happen unless the spring breaks for some reason.