871N fractured valve

[bostonhatteras]

What a way to start the season! After idling out of long no wake zone I opened throttles expecting the usual bit of blueish smoke but this time the stbd engine gave a giant and dense gray smoke cloud. Throttled down, then up once to look at the smoke, then I shut it down. Locked the shaft and started back to dock. Started the engine to maneuver through two bridges but otherwise was off with shaft immobile. Just heavy blue smoke now. I have dealt with a burned valve before but this doesn’t look burned. Looks like it’s fractured, likely with the detached piece floating around somewhere. Any thoughts on what would cause this? I want to look for causes before I start disassembling things. Injector tip appears fully intact. All other cylinders are really nice looking with clearly defined injector spray pattern and light gray color throughout and minor carbon on valve faces. I would like to lap in one new valve and call it a day. I’ll bet when these heads were rebuilt I got used valves. These aren’t the original heads to the engine btw. Around 500 hours on these heads since installed and after rebuild. Engine ran fine previous to this, made full rpm under load and acceptable oil burn and oil in catch can.

 

[bostonhatteras]

Another pic of bad cylinder and a pic of a representative good cylinder Also all rings throughout engine are shiny with good spring.

 

[Captain Ralph]

Yep, rust spot on the valve seat got hot and all went down hill from there.

The blower should have pushed out any debris out the exhaust. Your piston and liner should be fine.

 

[bostonhatteras]

Yep, rust spot on the valve seat got hot and all went down hill from there.

The blower should have pushed out any debris out the exhaust. Your piston and liner should be fine.

Rust spot on valve seat? Never would have imagined that. Care to elaborate ? How would something like that be prevented ? I suppose it can’t get much worse. If scheduling is an issue maybe I’ll bypass the injector and run it on seven cylinders

 

[scottinsydney]

I am intrigued ... can you actually remove an injector / cylinder from the normal operation of a motor? I would presume this would be a very short term solution prior to the head/valves repair?

 

[Captain Ralph]

I have warned about this before on dock queens.
Open weather up the exhaust pipes.
Have made many repairs because of this. New seats and valves required.
Pull the head and with the correct tools, repairs can be preformed on board.

The debris is usually blown out but inspect the injector tip well just in case.

I would not try to bypass the injector. Run her if needed but get her fixed promptly.
The smoke is un-burned fuel getting ignited from the other exhaust ports in the exhaust manifold.

 

[bostonhatteras]

I am intrigued ... can you actually remove an injector / cylinder from the normal operation of a motor? I would presume this would be a very short term solution prior to the head/valves repair?

remove the fuel jumper lines to the injector/bypass the injector. Its short term but it can be done

 

[bostonhatteras]

I have warned about this before on dock queens.
Open weather up the exhaust pipes.
Have made many repairs because of this. New seats and valves required.
Pull the head and with the correct tools, repairs can be preformed on board.

The debris is usually blown out but inspect the injector tip well just in case.

I would not try to bypass the injector. Run her if needed but get her fixed promptly.
The smoke is un-burned fuel getting ignited from the other exhaust ports in the exhaust manifold.

Thanks Ralph Fixing is the way i intend to go.

 

[bostonhatteras]

Reading the 1969 edition of the DD operators manual under 30 days or longer storage gives this interesting piece of advice (see picture). A rust preventative throughout the fuel and exhaust system after 15 minutes running. The valvoline product is still available

 

[whoover]

I ran a cocktail in my boat for winter layup. I filled the racors with a mix of 1/2 gallon of fuel, 2 quarts of SAE 30 oil and 2 quarts of Lucas. It's smoked like crazy but was well lubricated.

Walt Hoover

 

[Timeless72]

Are you going to work with Mango again? I remember you mentioning he rebuilt these in a thread a while back.

 

[bostonhatteras]

I ran a cocktail in my boat for winter layup. I filled the racors with a mix of 1/2 gallon of fuel, 2 quarts of SAE 30 oil and 2 quarts of Lucas. It's smoked like crazy but was well lubricated.

Walt Hoover

This tactyl product isn’t expensive I think I’m going to rig up an auxiliary tank I can place before the primary filters. Hell of a lot more convenient than pulling heads and losing sea time

 

[bostonhatteras]

This tactyl product isn’t expensive I think I’m going to rig up an auxiliary tank I can place before the primary filters. Hell of a lot more convenient than pulling heads and losing sea time

Pics of the offending valve and seat Full valve job on that side just to be sure. Hopefully up this week

 

[Captain Ralph]

Yep..

 

[bostonhatteras]

Going to one of those summers it seems. New injector seizes two hours in. I'm going to keep an injector aboard with timing tool and new jumpers from now on.

 

[rustybucket]

Ouch! Would be worth pulling the injector apart and see what seized it. May also be worth taking a look at your fuel and fuel filters? Algae/debris/water can be hell on injectors.

 

[bostonhatteras]

Ouch! Would be worth pulling the injector apart and see what seized it. May also be worth taking a look at your fuel and fuel filters? Algae/debris/water can be hell on injectors.

I think its simply low quality assurance. Filters were only a few hours in when the burned valve occured and tanks were emptied and washed with oxalic acid, flushed with water a few times and air blower dried three years ago. I did start with the basics when engine shut down, check tank level, swap filters, run on external fuel source, open governor and see if rack rods move, lastly take off valve cover and see bad injector. Who knows what Interstate Mcbee would come up with to deny warranty / refund if they see it taken apart.

 

[Captain Ralph]

Was the new injector(s?) pop tested before you plugged it in or rite from the shelf/supplier?
I have always recommended getting your injectors pop & matched before plugging them in.

 

[bostonhatteras]

Was the new injector(s?) pop tested before you plugged it in or rite from the shelf/supplier?
I have always recommended getting your injectors pop & matched before plugging them in.

only one, and to replace the injector from the damaged cylinder. Right out of the box.

How long does the test operate the injector?

 

[Captain Ralph]

My injector shop sees me coming.
Usually with a box or two of donuts, coffee and treats.
AND up to 12 injectors.
They are for warned I'm coming so they can drag out the pop/test machine, blow off the dust and rig it for Detroit injectors.
While one tech is popping, matching flow and checking spray patterns, the rest of us are talking about the old days and calling each other names.
If I'm there when they open, Worse case the next morning ready for pick up.
Every injector starts with about 10 minutes and up to 20 minutes run time. Amp meter helps on plunger draw. If repairs or adjustments are made probably more run time.
The tech could tell witch injector had the problem clean, adjust or rebuild and test again.
I request to repair injectors, rarely replace.
By the end of the run, All injectors are tested well and matched.
Every lung gets the same fuel, same pattern at the same rack position.
Never (NEVER) had an injector issue after these extra steps.

I have had piles of issues from off the shelf/out of the box injectors near every time.
I remember one was perfect until it was clamped down. Minutes later it was hung up.
Even for a single well rebuilt injector by some child in another country, there is no way it will flow near what is already in the engine. I pull them all and have them tested and matched.
Did I mention; Never (NEVER) had an injector issue after these extra steps.

Yes, It cost extra bux. But when it is together and delivered, you know it is absolutely the best it can be.