3126 smoke part 2

[DagoBy]

OK. Tachs work better. They showed 2850 at WOT. GPS said 34 mph. 1/2 fuel 3/4 water and 3 normal sized folks on board. I watched as closely as I could and it appears both engines are smoking. smoke is grayish and just hangs in a fog behind the path of the boat. It is not heavy, but it is definately there. I looked back at my survey and noticed that it said the air intake heater(this is probably the wrong terminology) was sticking on after the port engine was up to operating temp,,,,,,could this cause the smoke??

 

[BonBini]

"Air Intake Heater" wont give you smoke. Air Intake heater warms up inlet air to help reduce smoke on start/warm up... Aftercooler and piston oil jets cool the pistons so they won't burn under load. With the air intake heater running all the time you will have some higher than normal cylinder temps, but this wont make your engine smoke. I believe there is a temp sensor that simply shuts off the heater grid.

You posted in the other post you had a short block and turbo put in. Most likely got a remanufactured cylinder head too... Typically cleaned and reusing the aftercooler, fuel system and all the jewelry would be the norm. Including re using the injectors. Do you have 600 ish hours on your injectors in both engines?

 

[douglee25]

Ron - Are you leaning towards a fuel atomization problem? I would think either injectors or something is wrong with the fuel itself. Are you using any fuel additives? Has a dock attendant ever accidentally put gas into the tanks?

Doug

 

[fwebster]

But he's running at rated rpm under load @ WOT and the boat is flying for 30,000 lbs at 34mph ...........Is there a problem and if so, what could be affecting both engines? Remember this boat has under water exhaust outlets.......he could be seeing vapor rising to the surface after the boat passes.

 

[DagoBy]

Ron, yes I have 614 hours on the injectors. I faithfully use the diesel power service fuel additive and also an additive for growth in the fuel system. Never had any gas accidentally put in the tanks. FW- I can see the smoke for a 1/4 mile behind the boat, would vapor linger that long?

 

[JC3]

What was your engine temps at WOT? JC

 

[DagoBy]

Engine temps were @ 180 or just a little over (1or2 degrees)

 

[JC3]

2850 rpm, temps 180, great speed. This doesnt look like an engine thats having trouble.
What did oil anlysis show? JC

 

[BonBini]

Dagoby: It really sounds like your seeing hot unburnt fuel. It would be blacker in color if it were more than just a little bit. 5 - 10 horse power of unburnt fuel out of a 400+ hp 3126 will be a light haze as you describe. It also sounds like a set of scored injectors... Ie: The 3126 has no fuel timing advance mechanism and relies soley on the extremely high injection pressure to get a good/complete burn within the cylinder. With a little scoring, the injector takes a bit longer to build enough pressure to start a spray. With a delayed spray, the burn is cooler and takes longer. Once past the sweet spot in the cylinder, the burn is done and the smoke exits.

With the reduction of sulfur in fuel, Cat seen an awfully lot of injector and injection pump scoring. Ultra high efficiency fuel filters and a lubricity additive for fuel came out to combat the problem. Some pumps for older engines have even been redesigned with lubrication lands cut in the plungers… I don’t know if Power Service has a lubricant in it or not. You may even have a ton of air going through the fuel system causing slow timing.

If your 3126’s are getting good non aerated fuel flow, good fuel and boost pressure, and your still seeing unburnt fuel smoke, then your injectors are shot.

It was impressive to see your turning 2850 wot under load. I’m assuming your hp ratings are at 2800. What are your engines ser #’s? I’m just a little curious on your ratings!

 

[Turtlesboat]

hell, i don't run that well. I also have a ton of weight on the butt with the TNT and dink. Those are some good stats.