Official Caterpillar3116/3126 Thread

[Maybe A Dancer]

THANKS - will do !

these boost gauges are electric......

 

[Strecker25]

THANKS - will do !

these boost gauges are electric......

Which one is the variable, the lower one? What’s the cat spec for max boost on your engine?

The 3126 is internally wsstegated around 27psi, but Im fairly certain the 3116’s don’t have one at all, correct?

Btw those EGTs are fantastic

 

[Maybe A Dancer]

Which one is the variable, the lower one? What’s the cat spec for max boost on your engine?

The 3126 is internally wsstegated around 27psi, but Im fairly certain the 3116’s don’t have one at all, correct?

Btw those EGTs are fantastic

Hey, Thats a good point.

Had'nt considered THAT !!!

Here's some info.

These photos/data taken after a month on the hard for a couple of things including new barrier coat, bottom job & tiny prop tweak.

Just splashed, filled up fuel and water.

please ignore the yard dirt on the gauges.

These two are at 2400 RPM running 23.5 kts/27 MPH

PORT 2400:

Here's STBD 2400 - (Port boost visible at left)

Here's the WOT data, full fuel, full water

32,000 lb boat running 31 MPH WOT



PORT WOT:

STARBOARD WOT:

 

[Maybe A Dancer]

So, what Ryan has exposed is - appears the PORT is fine, running as it has been and throwing data consistent since I installed the boost gauges and the STBD is now showing a significantly higher number that it has been since boost gauges installed.

Wastegate ?

My old Yanmars had this feature clearly visible.

I have no idea on the 3126 - Nothing that I recall external to the turbo.

Anyone have any ideas on this?

BEST !

RWS

 

[techmitch]

Hey, Thats a good point.

Had'nt considered THAT !!!

Here's some info.

These photos/data taken after a month on the hard for a couple of things including new barrier coat, bottom job & tiny prop tweak.

Just splashed, filled up fuel and water.

please ignore the yard dirt on the gauges.

These two are at 2400 RPM running 23.5 kts/27 MPH

PORT 2400:




View attachment 161379

Here's STBD 2400 - (Port boost visible at left)
View attachment 161380



Here's the WOT data, full fuel, full water

32,000 lb boat running 31 MPH WOT



PORT WOT:

View attachment 161381

STARBOARD WOT:

View attachment 161382

Coolant temp looks really low in last pic.

 

[Maybe A Dancer]

Coolant temp looks really low in last pic.

Good catch, but those are the transmission temp gauges.

I have the sensors on the side coming out of the cooler.

Will swap them when I replace the transmission cooler lines later this season as a part of my "get the boat to baseline" process which has been ongoing since I got her in December 2021.

BEST !

RWS

 

[dtfeld]

THANKS - will do !

these boost gauges are electric......

Then they are even more suspect...

Swap senders. If problem follows...bad sender.

 

[Strecker25]

Sorry I assumed you had 3116’s - I do believe all the 3126’s are wastegated (you can see the silicone hose external to the turbo from the compressor housing to the actuator can) but I’d think it’s irrelevant to this problem since your anomaly is actually higher boost on one, versus lower.

I’d swap the sender first like Dave said so you isolate the problem.

One thing I can’t figure out from the pictures since once is in MPG mode - is the higher boost engine also burning more fuel?

 

[dtfeld]

Sorry I assumed you had 3116’s - I do believe all the 3126’s are wastegated (you can see the silicone hose external to the turbo from the compressor housing to the actuator can) but I’d think it’s irrelevant to this problem since your anomaly is actually higher boost on one, versus lower.

I’d swap the sender first like Dave said so you isolate the problem.

One thing I can’t figure out from the pictures since once is in MPG mode - is the higher boost engine also burning more fuel?

 

[dtfeld]

Brings up an interesting point…these are mechanical, so fuel isn’t based on boost. Throttle position dictates fuel? Hence the ability to over fuel if RPM isn’t able to reach WOT specification.

Regardless if youre WOT RPMs are 2600, 2850 or something else, engine is going to fuel it if as it were turning 2800. Lower RPM are overfueled and generate excessive heat, and usually black smoke.

I’d have to think about it, but I’m on a tropical beach and alcohol may or may not be involved!

Happy Easter!

 

[Maybe A Dancer]

Coolant in and out hoses and oil in and out.

No visible waste gate or any mechanical actuator that I can see.

======================================

I ran these Floscans with my Yanmars in my previous 10 meter International and one engine always burned about 3% more than the other.

They're always close, but never truly match exactly.

I've been told this inconsistency is consistent, as one prop may be slightly different than the other and that one side (can't remember which) always works harder than the other, bit the difference is negligible.

IMHO the 2 gallons over the 63 burned is not really significant, but that's just my view.

===============================

No smoke, no soot, transom and sides are CLEAN , REALLY CLEAN !

BEST !

RWS

 

[Strecker25]

Coolant in and out hoses and oil in and out.

No visible waste gate or any mechanical actuator that I can see.

======================================

I ran these Floscans with my Yanmars in my previous 10 meter International and one engine always burned about 3% more than the other.

They're always close, but never truly match exactly.

I've been told this inconsistency is consistent, as one prop may be slightly different than the other and that one side (can't remember which) always works harder than the other, bit the difference is negligible.

IMHO the 2 gallons over the 63 burned is not really significant, but that's just my view.

===============================

No smoke, no soot, transom and sides are CLEAN , REALLY CLEAN !

BEST !

RWS

it would look like this blue hose. Our 350hp variant has them, yours may not.

Even if you have them it’s unlikely to be your root cause unless it was stuck close and not allowing that side to bypass the turbine at high boost.

Swap the sensors first, not worth troubleshooting further until you know for certain it’s not instrumentation issue

 

[Maybe A Dancer]

The turbos have no wastegate.

Agree on the senders. Will swap out before the next sojourn and report results.

Meanwhile, here's the data from yesterday's run:

corrected>>>>

HOURS RUN = 2.8

STATUTE MILES RUN = 41.3

TOTAL GALLONS BURNED = 51.6

SMPG = .8003

GALLONS PER HOUR BOTH ENGINES = 14.7

These numbers are far better after burning off more fuel.

As FrankW states, these hulls typically are load sensitive.

BEST !

RWS

 

[Magic]

The turbos have no wastegate.

Agree on the senders. Will swap out before the next sojourn and report results.

Meanwhile, here's the data from yesterday's run:

corrected>>>>

HOURS RUN = 2.8

STATUTE MILES RUN = 41.3

TOTAL GALLONS BURNED = 51.6

SMPG = .8003

GALLONS PER HOUR BOTH ENGINES = 14.7

These numbers are far better after burning off more fuel.

As FrankW states, these hulls typically are load sensitive.

BEST !

RWS

Any chance you can post a pic of your senders? Presumably these are custom fit?? How did you do this?

Thanks

 

[Maybe A Dancer]

Will post photos of the boost sending units.

They simply screw into the top of the aftercooler.....

As for the electric pyrometers, they MUST have the correct wire and it must be the correct length.

Back in the 1980's, when I ran a trucking company running MACK Trucks, with INTERCOOLERS (similar to aftercoolers on the CATS, but were air to air. We fitted them with BOOST and PYROMETER gauges, which were indispensable when troubleshooting a problem, or avoiding a failure.

BEST !

RWS

 

[Maybe A Dancer]

With the one boost gauge HIGHER than it has been, I suspect a defective sending unit.

Swapping them out will likely veirify.

Meanwhile, here's the photos as promised:

I have so much additional non-factory wiring between the helm and engine room I planned ahead and installed a wiring conduit under the cockpit seating.

There is an identical conduit running in the ceiling of the engine room.

These are available from WW Grainger or McMaster Carr, and make a HUGE difference in the end result.

BEST !

RWS

 

[Strecker25]

not that its difficult to swap them but is there any troubleshooting the manufacturer provides to test resistance or something? I know my transmission pressure gauges have a spec that can be checked with a MM

 

[Maybe A Dancer]

OK - - Here's the follow up.

Prior to taking the boat out for a weekend at TWEEN WATERS INN on Captiva Island, I was going to swap out the electric sending units.

Found a less than totally tight spade terminal on the engine showing the higher values.

Must have been me when changing the aftercooler zincs.

Tightened up the spade terminal and no more high readings.

THANK YOU ALL for sharing the knowledge & suggestions.

BEST !

RWS

 

[Strecker25]

OK - - Here's the follow up.

Prior to taking the boat out for a weekend at TWEEN WATERS INN on Captiva Island, I was going to swap out the electric sending units.

Found a less than totally tight spade terminal on the engine showing the higher values.

Must have been me when changing the aftercooler zincs.

Tightened up the spade terminal and no more high readings.

THANK YOU ALL for sharing the knowledge & suggestions.

BEST !

RWS

Easy fix! Nice!

 

[Maybe A Dancer]

RE: the posts above regarding fuel burn.

This particular boat, for whatever reason has a verified (Floscan) sweet spot a bit higher than most have reported here.

Once she gets to a 50% fuel load, her efficiencies really improve.

The data shown below are with 100% full water @ 100 gallons and 50% fuel 206/400 gallons.

This boat does weigh in on the heavy side at 32,000 lbs fully loaded water and fuel.

I believe the weight has to do with her two thrusters, 2 additional thruster batteries, Cablemaster, LVP flooring plus my spares & tools and lots of extra wiring

In this case, 2,300 RPM seems to be the magic number.

1996 450DA running 3126 Cats

Heres the data:

2300 RPM

.82 NMPG = .943 SMPG at 26 MPH

Increasing RPM to 2400 yields the following data:

.81 NMPG = .932 SMPG at 27.2 MPH

It should be noted that with full fuel, (same water) efficiencies are not this good.

Same goes for rough water and wind.

Of note: immediately after the required monthly bottom cleaning, efficiencies are better than this data.

Reading through CSR, seems like everyone talks about 2150 as the magic number, however this is not the case for this particular boat.

And yes, she is hitting 2800 RPM WOT.

All data taken with just under full tabs being applied.

Will be doing a run to St Pete Beach next month and will have an opportunity to collect data at several different fuel levels. Let's see how that looks.

Meanwhile, I'm really happy with these numbers.

As a comparison, my previous boat, 1983 Trojan International 10 meter (33') x 13' beam had twin Yanmar 315 turbodiesels that I refitted in 2005. WOT 3800-4000 RPM

Same Floscans (I swapped them)

Her most efficient on plane speed was 2500 RPM 16 SMPH @ 1.4 SMPG, low speed cruise, however we'd typically run 3200 RPM 22-23 MPH at 1.3 SMPG
14,000 lbs

That boat weighed in fully loaded, fuel, water, spares at 18,000 lbs.

If you consider the 450 DA is about 12' longer, 1' wider and 7 tons heavier, it's surprising to get the efficiencies shown at higher speeds.

3-4 miles per hour might not seem like much, but on a six hour run, its about an hour difference in travel time.

Now that boat would regularly run well over 3SMPG at displacement speeds, but let's not go there.....

Anyhow, I believe these are really respectable numbers, and couldn't be happier than I am with the 450DA/3126 combination.

BEST !

RWS