Wow..... Lookie what I found!

[Genesis]

You're going to love this one.

Replacing injectors on a friend's boat today. Unbolt the first hole's fuel pipes, set aside, unbolt the towers, and..... heh, what's this?

The nasty part is that I can't find an oiling problem. BUT - unbolted another hole and that shaft is scored up pretty bad too (although not broken!), and the bearings in the rockers look like hell.

The bolt's oil holes are clear, the shaft and journals in the rockers were full of oil, no evidence of being dry. But obviously, they have been/or are. Not good.

The only operational oddity is that this guy likes his idle set low. Like in the 400 RPM range, and it DOES "ring the chimes" when hot at idle sometimes.

The current prescription is to change all six holes worth of rockers, bridges (they are showing uneven wear too) and rocker shafts, plus the tower and bolts on the one that fractured. Oh, and raise the idle up into the 550-575 range. I only hope that whatever led to this hasn't infected the mains and'/or cam bearings too, because if it has, this engine is going to go "boom" soon. It's running fine; injectors were being changed for power calibration reasons, not due to operational problems.

Can you say "lucky"? How he avoided having this come apart on him under load is beyond me. It goes to show you - Detroits will put up with a LOT wrong with them and not go "boom" - even when you think they should have.

Sorry about the crap focus - it was the cam in my phone, all I had...... and yes, that discoloration IS bearing material from the rockers.

 

[Traveler 45C]

I've never had my valve covers off so I don't know what the heck is laying there on the dock. What is it and what does, "ring the chimes" mean?

 

[Genesis]

That's a rocker shaft.

It is the pivot point on which the rockers that actuate the valves and injectors ride.

It is not supposed to be scored like that, and its also not supposed to have the end broken either

The bolts holding the towers down go through the holes. Normally that shaft does not move - the rockers pivot on it, but the shaft itself is held by the bolts and the towers. Oil is delivered from the cylinder head galleries up through the bolts (they're drilled), then up the tower, into drilled holes in the shaft and then to the rockers - all under pressure.

When they snap like this its for one of two reasons:

1. The tower wasn't tightened down, the shaft was binding, and someone started the engine. Bad. The towers WERE torqued properly, so that's eliminated.

2. There was a lubrication failure, the rocker bound on the shaft, and literally twisted it hard enough to break it.

The latter is the case here. At first I thought it was just plain bad. Well, when I removed it, the scoring became apparent. The nasty part is that there obviously was oil flow into there - it wasn't dry anywhere along its run - but also obviously, it HAD BEEN or it wouldn't look like that. The oil holes in the shaft and the bolts are clear.

Not good as there's no immediately-apparent reason for this.

This engine was "overhauled" before the current owner bought it, but he's not sure whether the heads were replaced. He's got about 600 hours on it to this point since he bought it without serious incident. Its possible these are the original heads (only two are on the invoices, and he has two engines, so there should be four, right? ) If these are original the question still remains how you manage to do a major and not inspect those parts. The other explanations are kinda ugly - one might even question if that engine got a "wall job"! The current owner has never had the injectors out of this motor since he bought the boat; other than adjusting valves and such he's not had a reason to screw with it, so there'd be no way for him to know, since the shaft appeared secure until the tower was loosened.

If the damage is recent then this gets very interesting because without an apparent cause I can only surmise that the very low idle this guy runs (albiet within DD spec) has led to insufficient oil in the top galleries when at hot idle and that was the root cause. In any event the condition of the cam, cam bearings and mains are now suspect, although hot oil pressure at running RPMs is reported as fine. The bad news is that damage to bearings like this, once it starts, is progressive until destruction - there's really nothing you can do about it other than to replace the affected parts.

The other ugly part is that about a month ago we replaced the injectors in the OTHER engine. I didn't pull the rocker shafts because I had no reason to - none were broken and nothing aroused suspicion, but now I'm starting to wonder if THEY have similar damage.....

Bad mojo. The part that led me to recommend that my buddy go buy a bunch of lotto tickets is that broken like this its unbelieveable that it stayed in place in the tower. If it had not the valves and/or injector would have almost certainly bound up while "down" (pushrods extended) with extremely bad results. In an extreme case the followers can be damaged (time to pull the cylinder head) or even worse, the cam could be lunched (you don't want to know)

Anyway, that the engine was running fine screwed up like this is incredible. The ugly part is that I pulled another shaft on the same bank to check it and while its not broken it too is scored and shows evidence of bearing material transfer from the rockers (again, lube problems)

Never put it past a Detroit to keep running with no apparent indication of trouble even when totally screwed up.

The parts on the top end that NEED to be replaced total up to about a grand. There's no way to know, however, if there's a ticking bomb in the mains or camshafts - all he can really do is replace the obviously affected pieces, bump up the idle, make sure that oiling is sufficient, and run it in the hope that there hasn't been anything really ugly done to the bearings we can't get to in order to check them. If it goes "boom" then its going to be coming out of the boat and may get longblocked as in all probability it will be either main or cam problems that make that necessary.

I hate finding stuff like this and I hate it even more when I can't find the original cause.

"Ring the chimes" - ding the low oil pressure bell when at hot idle, especially in gear.