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08-15-2017, 08:05 PM
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#1
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TF Site Team/Forum Founder
City: League City, Tx
Vessel Name: Floatsome & Jetsome
Vessel Model: Meridian 411
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Pyro readings on Cummins 6BTA
Ok...I am finishing up my panel project and gotta get some things squared away. One of them is the pyro gauges. What is the "normal range" of pyro readings??? I am talking while in the boost? I cruise in the 2200-2400RPM range.
My starboard engine runs at about 600 degrees at around 2400rpms. The port engine is showing 1000.
I did call Seaboard as that is where I purchased the gauge. One of their techs answered that it should be in the 900-1200 range...putting that 1000 degree right in the wheelhouse and the 600 degree reading a little "cool". He handed off the phone to Tony. Tony said the normal range is more like 350-750....putting that 600 reading right in the wheelhouse and the other engine a little on the hot side.
On the engine spec sheet it shows 905. It does not give a range or a max. But it is annotated that figure is at rated power....basically assuming WOT is what they mean.
Just wondering what kind of reading y'all are getting for people that have B series Diamonds with pyro gauges???
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Prairie 29...Perkins 4236...Sold
Mainship Pilot 30...Yanmar 4LHA-STP...Sold
Carver 356...T-Cummins 330B...Sold
Meridian 411...T-Cummins 450C
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08-15-2017, 08:44 PM
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#2
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Grand Vizier
Join Date: Jan 2010
Posts: 3,815
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Quote:
Originally Posted by Baker
Ok...I am finishing up my panel project and gotta get some things squared away. One of them is the pyro gauges. What is the "normal range" of pyro readings??? I am talking while in the boost? I cruise in the 2200-2400RPM range.
My starboard engine runs at about 600 degrees at around 2400rpms. The port engine is showing 1000.
I did call Seaboard as that is where I purchased the gauge. One of their techs answered that it should be in the 900-1200 range...putting that 1000 degree right in the wheelhouse and the 600 degree reading a little "cool". He handed off the phone to Tony. Tony said the normal range is more like 350-750....putting that 600 reading right in the wheelhouse and the other engine a little on the hot side.
On the engine spec sheet it shows 905. It does not give a range or a max. But it is annotated that figure is at rated power....basically assuming WOT is what they mean.
Just wondering what kind of reading y'all are getting for people that have B series Diamonds with pyro gauges???
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1000 degrees seems a bit too high. Prior to adjusting my prop, I could get to around 800 degrees at near WOT on a CAT 3306, which the prop guy thought was an indication of over propping. Now with a flatter wheel, it is around 700 degrees. Do you reckon both wheels have the same pitch?
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08-15-2017, 08:53 PM
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#3
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TF Site Team
City: Brisbane
Vessel Name: Insequent
Vessel Model: Ocean Alexander 50 Mk I
Join Date: Mar 2012
Posts: 4,260
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JD's here, but before that Cummins 555's. Readings about the same for both brands, and doubt that it is engine brand specific. Assuming everyone is using °F then I only see 900 when near full power. At my low speed/eco cruise its more like 400-450.
Try swapping your senders between engines. I suspect one of them at least is dodgy, perhaps both. I think the senders are quite cheap, so suggest that you replace both anyway.
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Brian
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08-15-2017, 08:57 PM
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#4
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TF Site Team/Forum Founder
City: League City, Tx
Vessel Name: Floatsome & Jetsome
Vessel Model: Meridian 411
Join Date: Oct 2007
Posts: 7,332
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Quote:
Originally Posted by Delfin
Do you reckon both wheels have the same pitch?
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Props were redone 3 months ago... I gotta assume they knew what they were doing. Also, there is absolutely no other symptom...no black smoke on that side....no excessive fuel burn on that side.
I ask a theoretical question. Heat does not come out of nowhere. I would think heat in a diesel engine can only come from one thing....FUEL!!! Is there anywhere else it could come from?? In a gasoline engine, actually leaning the fuel can cause an increase in EGT. Can the same be said for diesel???
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Prairie 29...Perkins 4236...Sold
Mainship Pilot 30...Yanmar 4LHA-STP...Sold
Carver 356...T-Cummins 330B...Sold
Meridian 411...T-Cummins 450C
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08-15-2017, 08:58 PM
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#5
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TF Site Team/Forum Founder
City: League City, Tx
Vessel Name: Floatsome & Jetsome
Vessel Model: Meridian 411
Join Date: Oct 2007
Posts: 7,332
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Quote:
Originally Posted by Insequent
Try swapping your senders between engines. I suspect one of them at least is dodgy, perhaps both. I think the senders are quite cheap, so suggest that you replace both anyway.
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They are brand new. BUT, I will switch the gauges...not the senders....since that would be easier.
__________________
Prairie 29...Perkins 4236...Sold
Mainship Pilot 30...Yanmar 4LHA-STP...Sold
Carver 356...T-Cummins 330B...Sold
Meridian 411...T-Cummins 450C
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08-15-2017, 09:07 PM
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#6
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Moderator Emeritus
City: SEWARD ALASKA
Vessel Name: DOS PECES
Vessel Model: BAYLINER 4788
Join Date: Feb 2011
Posts: 6,263
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I have a pair of those same engines
A bit less than 900 is normal for my properly proper boat at a cruise of 2500
At displacement speeds I see about 600
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08-15-2017, 09:14 PM
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#7
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TF Site Team/Forum Founder
City: League City, Tx
Vessel Name: Floatsome & Jetsome
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Quote:
Originally Posted by ksanders
I have a pair of those same engines
A bit less than 900 is normal for my properly proper boat at a cruise of 2500
At displacement speeds I see about 600
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Hmmmmm....very interesting. Mine actually decrease to 900 at WOT.
__________________
Prairie 29...Perkins 4236...Sold
Mainship Pilot 30...Yanmar 4LHA-STP...Sold
Carver 356...T-Cummins 330B...Sold
Meridian 411...T-Cummins 450C
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08-15-2017, 10:05 PM
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#8
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Grand Vizier
Join Date: Jan 2010
Posts: 3,815
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Quote:
Originally Posted by Baker
Hmmmmm....very interesting. Mine actually decrease to 900 at WOT.
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Boy, that just doesn't sound right. More fuel + more work should mean higher exhaust gas temps, not lower. Have you checked air filters? You're an aviator, right? Reduce the fuel to air ratio, higher EGT, increase fuel to air, lower EGT. But maybe that only applies to gas engines? Just for kicks, perhaps remove the air filter on the engine with the higher temps to see if there is any effect?
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08-15-2017, 10:06 PM
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#9
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Moderator Emeritus
City: SEWARD ALASKA
Vessel Name: DOS PECES
Vessel Model: BAYLINER 4788
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Posts: 6,263
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Quote:
Originally Posted by Baker
Hmmmmm....very interesting. Mine actually decrease to 900 at WOT.
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I never really looked at that too much.
I can say with mine I cant get the EGT above 900 even fully loaded at WOT.
EGT seems to be based on load not RPM. If at WOT your boat is decreading in EGT then your load muct be going down.
At your cruise RPM are you on the "hump" of bow up, maximum drag, or are you over the "hump"
I run my boat at 2500 fast cruise, not because I like that RPM, but because I like the speed of 1415 kn ots which puts me "over the hump"
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08-15-2017, 10:20 PM
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#10
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Guru
City: League City, TX
Vessel Name: Pelago
Vessel Model: Wellcraft 3300 Coastal
Join Date: Aug 2011
Posts: 1,069
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Quote:
Originally Posted by Baker
Hmmmmm....very interesting. Mine actually decrease to 900 at WOT.
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That is not uncommon with Cummins BTA's. Part-load can often produce the highest EGT's. The condition of the turbos, aftercoolers, air filters, exhaust backpressure, engine loading and many other factors I'm sure can all contribute to higher/different EGT's.
Like you, my owner's manual shows 905° F as max at WOT. I'm comfortable with anything below that number. The most important thing I look for are the temp and boost trends. Significant or sudden changes require investigation.
IMHO, you just can't have too much accurate information on these little white monsters.
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Larry
M/V Pelago
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08-15-2017, 10:41 PM
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#11
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TF Site Team/Forum Founder
City: League City, Tx
Vessel Name: Floatsome & Jetsome
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Quote:
Originally Posted by LarryM
That is not uncommon with Cummins BTA's. Part-load can often produce the highest EGT's. The condition of the turbos, aftercoolers, air filters, exhaust backpressure, engine loading and many other factors I'm sure can all contribute to higher/different EGT's.
Like you, my owner's manual shows 905° F as max at WOT. I'm comfortable with anything below that number. The most important thing I look for are the temp and boost trends. Significant or sudden changes require investigation.
IMHO, you just can't have too much accurate information on these little white monsters.
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Larry, you speak like you have pyro gauges. What do yours read at various RPMs?
__________________
Prairie 29...Perkins 4236...Sold
Mainship Pilot 30...Yanmar 4LHA-STP...Sold
Carver 356...T-Cummins 330B...Sold
Meridian 411...T-Cummins 450C
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08-15-2017, 10:43 PM
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#12
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TF Site Team/Forum Founder
City: League City, Tx
Vessel Name: Floatsome & Jetsome
Vessel Model: Meridian 411
Join Date: Oct 2007
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Quote:
Originally Posted by Delfin
Boy, that just doesn't sound right. More fuel + more work should mean higher exhaust gas temps, not lower. Have you checked air filters? You're an aviator, right? Reduce the fuel to air ratio, higher EGT, increase fuel to air, lower EGT. But maybe that only applies to gas engines? Just for kicks, perhaps remove the air filter on the engine with the higher temps to see if there is any effect?
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I asked that question above. I honestly don't think leaning out a Diesel engine would cause EGTs to rise. And after research, it is somewhat common for a drop in EGT at WOT. Maybe more airflow...who knows.
__________________
Prairie 29...Perkins 4236...Sold
Mainship Pilot 30...Yanmar 4LHA-STP...Sold
Carver 356...T-Cummins 330B...Sold
Meridian 411...T-Cummins 450C
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08-15-2017, 10:45 PM
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#13
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TF Site Team/Forum Founder
City: League City, Tx
Vessel Name: Floatsome & Jetsome
Vessel Model: Meridian 411
Join Date: Oct 2007
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Quote:
Originally Posted by ksanders
I never really looked at that too much.
At your cruise RPM are you on the "hump" of bow up, maximum drag, or are you over the "hump"
I run my boat at 2500 fast cruise, not because I like that RPM, but because I like the speed of 1415 kn ots which puts me "over the hump"
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Yeah, well over the hump. My hump is about 13 knots. 2400 yields about 18-19 knots. It seems to be a pretty happy spot.
__________________
Prairie 29...Perkins 4236...Sold
Mainship Pilot 30...Yanmar 4LHA-STP...Sold
Carver 356...T-Cummins 330B...Sold
Meridian 411...T-Cummins 450C
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08-15-2017, 11:52 PM
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#14
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Guru
City: League City, TX
Vessel Name: Pelago
Vessel Model: Wellcraft 3300 Coastal
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Posts: 1,069
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Quote:
Originally Posted by Baker
Larry, you speak like you have pyro gauges. What do yours read at various RPMs?
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John,
At WOT, 3,025 rpm and 29+ kt, about 825°. At high cruise, 2,550 rpm and 25kt, just under 900°, and at econo cruise, 2,200 rpm and 21kt, I see 575° or so. I'm propped very lightly and the boat is not heavy. It is fully on plane about 13-14kt and is very sensitive to its large tabs. Good trim and running angle makes a big difference. Full-auto Bennett ATP's are next
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Larry
M/V Pelago
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08-16-2017, 07:55 AM
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#15
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Guru
City: Northport
Join Date: Aug 2015
Posts: 2,046
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I do not have Cummin's engines but I have run pyro & boost gages on the last 3 boats with 6 cylinder 4 stroke turbo diesels. I have found them to be more valuable than any other gages on the boat. The EGT senders were always mounted immediately after the turbo outlet and the boost was read after the intercooler in the intake manifold area.
Readings are always within 950 max on the EGT with the gages beginning to move in the 1500 rpm area and builds to about 900 between 2200 and WOT of 3100. ON a really hot and humid day readings will rise to about 925 and when towing a larger RIB and maybe with a little bottom growth on a hot day readings will rise to 950 at max.
The gages always move in tandem with the boost gages so that they are just about equal at engine rpms that are within 25 or so.
I have always swapped gage sender lines at eth ages upon any installation to know that they are reasonably calibrated at the start.
Some things that will cause an EGT variations:
- sender not centered in exhaust flame kernel
- sender wires/connections not secure
- prop variances
- ambient heat and humidity
- a dozen barnacles on the prop or shaft
- air intake or boost
- exhaust restrictions due to design or condition
- Fuel or valve timing
- Poor injection patterns
IMO EGT and boost gages should really come on every marine turbo diesel 4 stroke.
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08-16-2017, 07:57 AM
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#16
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Guru
City: Northport
Join Date: Aug 2015
Posts: 2,046
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"My starboard engine runs at about 600 degrees at around 2400rpms. The port engine is showing 1000."
At this point when your EGT is really well out of balance what are your corresponding boost readings?
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08-16-2017, 08:00 AM
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#17
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Guru
Join Date: Jun 2008
Posts: 5,034
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I had a single 6BTA 270 (I repowered with it) in my previous boat.
My max EGT was around 925 F at WOT which was 2650 (50 over).
From my Dodge/Cummins pickup truck experience, leaning the fuel lowers EGT, while accelerating (or pulling a hill with a load) with black smoke (unburned fuel) increases EGT.
__________________
Jay Leonard
Ex boats: 1983 40 Albin trunk cabin, 1978 Mainship 34 Model 1
New Port Richey, Fl
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08-16-2017, 08:32 AM
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#18
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Guru
City: LI or Fla
Join Date: Jul 2013
Posts: 1,148
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I think the biggest thing out of all this is the large delta difference between the two, really need to sort that out and some OP's gave some good info on it.
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08-16-2017, 08:46 AM
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#19
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Technical Guru
City: Wilmington, NC
Vessel Name: Louisa
Vessel Model: Custom Built 38
Join Date: Jan 2014
Posts: 6,194
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I suspect a gauge issue or sensor issue. 1000 sounds a little high, 600 way low for a 330 running at 2400.
Are you monitoring charge air pressure (boost)? EGT and boost should track each other closely between twins at same load
Are your tachs accurate and you know engines are in fact sync'd?
What rpm do both engines reach at full power?
Normal on lots of engines for egt to rise a bit at part load. At full load there is lots of boost and so the excess air in the cylinder, beyond what is needed for combustion, rises on a percentage basis. So more air going out that was not involved in a burn.
Also some boats settle at slow planing speed and that raises load.
You should swap gauges. Then if no change swap probes. Hopefully that is possible without making a hash of your cable routing job.
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08-16-2017, 09:38 AM
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#20
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TF Site Team/Forum Founder
City: League City, Tx
Vessel Name: Floatsome & Jetsome
Vessel Model: Meridian 411
Join Date: Oct 2007
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Quote:
Originally Posted by smitty477
"My starboard engine runs at about 600 degrees at around 2400rpms. The port engine is showing 1000."
At this point when your EGT is really well out of balance what are your corresponding boost readings?
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Boosts are relatively low and within 2 psi of each other. 2400 is in the mid teens on boost.
__________________
Prairie 29...Perkins 4236...Sold
Mainship Pilot 30...Yanmar 4LHA-STP...Sold
Carver 356...T-Cummins 330B...Sold
Meridian 411...T-Cummins 450C
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