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DD 671 TI,Heavy smoke at idle. Cant figure out?? help pls.

Shamsul hasan

New member
Need Help!! I have a Trojan 12 meter with 671 TI,s. Since rebuilt my port engine gives white smoke on Idle and oil seeping from two exhaust ports of manufold, it gives black smoke on load max RPM 1800. Starboard engine no issues max RPM on load 2600 and no smoke. Have tried rack adjustment, governor, injector timming etc, nothing works..Need help please​
 
Hi, make sure air shutdown (between blower and intercooler) is open. If it smoked from day one i'm guessing cam shaft or gear train timing is wrong. Let us know what you find.
Charlie w.
 
Charlie, Tks for replying... I think may have a bigger problem? oil is seeping from the sump breather and Turbo exhaust also. The problem was from day one. Now it has increased. engines have not done more than 100 hrs. I guess, piston or rings? Air shutdown was the first thing i checked.
 
Remove inspection covers on side of engine block. You can check rings and piston top and sides. Doesn't sound good!! Don't run it till you find the problem. Could self destruct. Liner kits are easier to replace than engine blocks!
Charlie w
 
Only cylinder 4&5 leaking oil. The builder tells me, that i have not run the boat on load, should run it hard for 10 to 15 hours, oil will stop.. sounds strange to me?? He says; carbon will deposit and rings will set in.. I dont think its logical?? Blower and Turbo are fine...
 
I doubt that the engine is 800rpm off the WOT rpms of the other engine because it 'isn't run-in'. I assume that the prop on that side is perfectly clean? Is there a lot of blowby in that engine? Have you put a boost gauge on that engine to check the boost? It sounds like you might have a couple of bad cylinders, but there could be other causes and those are some simple checks that I would do.
 
The props are good.. I spoke directly to the mechanic about builders suggestion.. He disagreed and requested me not to start the engine.The blowby is lot more than ordinary. He inspected the engine, will open up the head after the weekend and inspect. Issue, most likely, rings or piston.
 
If the "white smoke" is raw fuel in those two cylinders washing down the cylinder walls then the rings would never seat and compression wouldn’t come up as a result. Agree that engine should not be operated until the cause of white smoke is foumd. This engine should be compression tested before doing anything else.

Just MY opinion.
 
If the "white smoke" is raw fuel in those two cylinders washing down the cylinder walls then the rings would never seat and compression wouldn’t come up as a result. Agree that engine should not be operated until the cause of white smoke is foumd. This engine should be compression tested before doing anything else.

Just MY opinion.
White smoke at start, but grey on 1200RPM without load. On load Black smoke. Anyways i am not starting the engine, till all tests are completed and cause identified.
 
"White smoke" IS raw, unignited fuel. Gray smoke is likely oil and black is partially, (poorly) burned fuel either suggesting low compression or over fueling. Or both.

Since each cylinder to be compression tested requires the injector to be removed, the injector tip can be examined and the the injector can be either bench tested or, at the least, the spray pattern can be looked at. So, I stand by my suggestion to compression test prior to any other procedures.
 
"White smoke" IS raw, unignited fuel. Gray smoke is likely oil and black is partially, (poorly) burned fuel either suggesting low compression or over fueling. Or both.

Since each cylinder to be compression tested requires the injector to be removed, the injector tip can be examined and the the injector can be either bench tested or, at the least, the spray pattern can be looked at. So, I stand by my suggestion to compression test prior to any other procedures.
Sure thing!! will get the compression test done first thing...
 
I don't think a valve guide seal could cause all the symptoms you have described with this engine. I will be very surprised if the low power complaint is remedied by replacing the seal.
Was the engine compression tested prior to tear down?
Here's hoping I'm wrong.
Good luck.
 
I haven't seen blockage in the fuel return line mentioned as a possible cause. Just tossing it out to see what others think.

Dan
 
I don't think a valve guide seal could cause all the symptoms you have described with this engine. I will be very surprised if the low power complaint is remedied by replacing the seal.
Was the engine compression tested prior to tear down?
Here's hoping I'm wrong.
Good luck.
I was surprised too. However, only cylinder no 5 piston was wet with oil.The liner, rings and pistons are ok. No oil in the blower. No oil in turbo intake, but turbo exhaust wet with oil. Cylinder 5 valve guide seal was busted and unseated. Guide completely free. Will let the mechanic know of your input. Really thankful.
Regards
Shams
 
Well, I suppose the oil flowing freely into the combustion chamber could have set up a situation that had the #5 piston doing all sorts of vertical velocity antics. It might light the oil as uncontrolled fuel and accelerate and then misfire a stroke or two later due to over fuel. This might get the governor into "playing catch up" and oscillating the weights in a very inefficient manner. Wouldn't happen with electronic control but with the mechanical governor I guess anything is possible.

We will see when you get it back together. Good luck and let us know what happens.
 
Well, I suppose the oil flowing freely into the combustion chamber could have set up a situation that had the #5 piston doing all sorts of vertical velocity antics. It might light the oil as uncontrolled fuel and accelerate and then misfire a stroke or two later due to over fuel. This might get the governor into "playing catch up" and oscillating the weights in a very inefficient manner. Wouldn't happen with electronic control but with the mechanical governor I guess anything is possible.

We will see when you get it back together. Good luck and let us know what happens.
Thanks!! have replaced all seals cylinder 6&5 as both had oil. Putting the engine together. Will test run Monday and post and update.
 
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