Exhaust gas temp (EGT). Advice needed

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Boatbore

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As many of you know I am in the process of rebuilding a 2002 sunseeker Superhawk 50. On the mechanical side I have removed all 3 engines and had them fully overhauled. They are now back in and purring perfectly (47 knots on sea trial ! ). However I have read a lot about EGT recently and especially on here, and can see the wisdom in being able to monitor this simple yet highly informative datapoint.

There is a an opportunity to mount the sensor after the turbo but before the water injection point which I think is perfect, however I am looking for advice on how to display the data. In theory it should be relatively simple to “send” the data to my new raymarine kit (axiom 12, and i70s) and then set it up to be easily read from the helm....... but I am struggling to get advice on how to do this, what sender to use etc etc.

All that I have read on here historically implies an independent gauge or read out for the data, and I wondered if anyone knew of a way or perhaps a particular sender that would relay the data to my Raymarine displays ?

All comments and advice welcome
 
Boatbore,

you could get NMEA2000 EGT sensors (well, not the sensor per se, but the h/w box that the nice ss metal shielded wire of the sensor terminates into)

Then, if your plotter supports PGN130311 or PGN130312 NMEA2000 sentences (and supports them fully!) then you'd be able to show EGT on it.
Else, you just get a full kit from Maretron as in sensors, black box in the e/r and a display to fit on your helm. Fully configurable to present what you wish. JFM is the resident expert on Maretron, I'm just a cheapskate hacking my way through NMEA2000...

cheers

V.
 
vas said:
Boatbore,

you could get NMEA2000 EGT sensors (well, not the sensor per se, but the h/w box that the nice ss metal shielded wire of the sensor terminates into)

Then, if your plotter supports PGN130311 or PGN130312 NMEA2000 sentences (and supports them fully!) then you'd be able to show EGT on it.

V.
Click to expand...

That’s what I am trying to do, but I seem to be struggling to find the right NMEA fluent black box !!!
 
burgundyben said:
Nice! .
Click to expand...

Well technically it was between 46.2 and 46.7 knots....... but I’m allowed to round up aren’t I ?

She is being copper coated below the waterline and it will be interesting to see if that top speed changes as per various claims....... probably the topic for a later post !
 
vas said:
Boatbore,

you could get NMEA2000 EGT sensors (well, not the sensor per se, but the h/w box that the nice ss metal shielded wire of the sensor terminates into)

Then, if your plotter supports PGN130311 or PGN130312 NMEA2000 sentences (and supports them fully!) then you'd be able to show EGT on it.
Else, you just get a full kit from Maretron as in sensors, black box in the e/r and a display to fit on your helm. Fully configurable to present what you wish. JFM is the resident expert on Maretron, I'm just a cheapskate hacking my way through NMEA2000...

cheers

V.
Click to expand...

Looking at the maretron website...... thanks to you...... I wonder if this would do the job ?
https://www.maretron.com/products/tmp100.php
 
Boatbore said:
Looking at the maretron website...... thanks to you...... I wonder if this would do the job ?
https://www.maretron.com/products/tmp100.php
Click to expand...

yep, but you unfortunately have 3 engines, right? So you need one and a half TMP100, make it two then :p
You also need a DSM* display, some cables, tees, etc. Dunno what else you have in terms of sensors (depth, wind, engine control to NMEA2000, etc) they can also be displayed on the DSM.
Again, if your plotter is NMEA2000 and supports all these, you can present them there with no need for extra displays, but again I don't know how many plotters you have on the helm, if only one, it's not realistic as you may want to have a look at where you're going and not only EGTs...

cheers

V.
 
vas said:
Again, if your plotter is NMEA2000 and supports all these, you can present them there with no need for extra displays, but again I don't know how many plotters you have on the helm, if only one, it's not realistic as you may want to have a look at where you're going and not only EGTs...

V.
Click to expand...

My plotter is a Raymarine axiom 12, and I also have an i70s display...... so between the 2 I should be able to see what I want. Also I can set an alarm range for the EGT so that I have the peace of mind an early warning if something is awry ! What I need to work out now is whether the Maretron will talk to the Raymarine stuff. The maretron datasheet suggests it “speaks” PGN128720.......whatever that means...... so I am going to get in touch with my Raymarine expert and find out of the axiom 12 can receive that code ? I think that all makes sense, But please correct me if I’m wrong.

And yes, you are correct that I will need 2x maretron TMP100, And 3x the high temp thermo probes, cable ties, a load of patience and probably a lottery win ! But I am trying to avoid the need for an extra screen...... it will play havoc with my fantastic new dashboard design !!! Lol.
 
Boatbore said:
My plotter is a Raymarine axiom 12, and I also have an i70s display...... so between the 2 I should be able to see what I want. Also I can set an alarm range for the EGT so that I have the peace of mind an early warning if something is awry ! What I need to work out now is whether the Maretron will talk to the Raymarine stuff. The maretron datasheet suggests it “speaks” PGN128720.......whatever that means...... so I am going to get in touch with my Raymarine expert and find out of the axiom 12 can receive that code ? I think that all makes sense, But please correct me if I’m wrong.

And yes, you are correct that I will need 2x maretron TMP100, And 3x the high temp thermo probes, cable ties, a load of patience and probably a lottery win ! But I am trying to avoid the need for an extra screen...... it will play havoc with my fantastic new dashboard design !!! Lol.
Click to expand...

boatbore,

too tired to do anything useful, so I did something useful for you :D

You DONT want/bother with the Maretron propriatary PGNs cause it's what it says, only for them!
You care about the PGNs that are periodically transmitted and within the standard (== viewable by other devices!)
so

TMP100 does transmit PGN130310, PGN130311 as well as PGN130312. Specs on Maretron sheet are a bit odd, I'd have thought that the first two are slower refresh on the bus compared to the 312, dunno and tbh doesn't make that much of a difference!
i70, installation and operation instructions two pages from the end (p.113) tells us that PGN130310 and 11 are supported.

So job done, no need to ask Raymarine experts on that.

What you need is:
2XTMP100
3Xthermocouples (I'd get 4 as it easy to damage them, take it easy on tightening them, don't ask how I know...)
one device to program/configure the two TMP100. Don't need to buy the DSM, get the USB100 or the IPG100 and use your laptop.
You obviously need a NMEA2000 bus, don't know if you already have one, if not get 3 Tees a long enough cable a power supply and you're done. That is assuming the Raymarine kit has proper NMEA2000 ports at the back, no idea! Well it has a port that accepts NMEA2000 according to the manual, but you obviously need an adapter as it's not proper NMEA2000 plug there.
So you need an adaptor cable for the i70 as well.

cheers

V.
 
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jimmy_the_builder said:
Where's Portofino when we need him... :D:D:D
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Sorry I can,t help with the electrotwackery stuff - connecting up etc .
Sounds like B.B. has sussed the importance anyhow .
Just to confirm with a 2 speed gearbox and high pitched (Rolla ? ) props if ever there was a need to see EGT,s then it’s this .
Getting that baby up and into top gear and settling on a none engine life shortening ( aka big bill territory) rpm is important.
Prop hygiene is paramount along with NOT adding Lardy extras .
Dirty props and the EGT,s for a given rpm rise - tells you they need a scape or need to ease off .

Hope the CC idea works in minimal drag too .Intersting to see how it works out on a plus 30 knot all day cruise boat .

Did you have to trim it @ 47 knots - flap down drag ? What rpm did they pull ?
Broshure / Broker talk is over 50 knots irrc ?

When’s it’s being sent back to SoF ?
 
Portofino said:
Sorry I can,t help with the electrotwackery stuff - connecting up etc .
Sounds like B.B. has sussed the importance anyhow .
Just to confirm with a 2 speed gearbox and high pitched (Rolla ? ) props if ever there was a need to see EGT,s then it’s this .*
Getting that baby up and into top gear and settling on a none engine life shortening ( aka big bill territory) rpm is important.
Prop hygiene is paramount along with NOT adding Lardy extras .
Dirty props and the EGT,s for a given rpm rise - tells you they need a scape or need to ease off .

Hope the CC idea works in minimal drag too .Intersting to see how it works out on a plus 30 knot all day cruise boat .

Did you have to trim it @ 47 knots - flap down drag ? What rpm did they pull ?
Broshure / Broker talk is over 50 knots irrc ?

When’s it’s being sent back to SoF ?
Click to expand...

*
https://www.thehulltruth.com/boating-forum/267549-yanmar-self-destructs.html
 
Hi Porto, I don’t want to go too far off thread here, but I have the original sunseeker delivery note that shows 47 knots flat out so getting pretty close 15 years later is reasonably good news I think. If the cc improves that further then that will be worth writing up on here and I will do that in due course.
In terms of weight, I removed the old generator (200kg) from inside the bathing platform and also the passarelle on the transom (100kg). I put in a modern generator (100kg) in the same place as the old one, and I have also added a seakeeper (250kg) but much further forward and closer to midships. This weight distribution seems to have been effective and my WOT top speeds of between 46.2 and 46.6 knots were with zero trim and the boat running straight and level. So far so good. RPM still needs some fine tuning, as there was some variation between the 3 engines between 3000 and 3200 revs. 3200 is the ideal WOT speed for these engines but Certainly at least one of the cables is stretched and I am going to replace all 3 throttle and all 3 gear cables and will be able to make a more accurate observation after that. It may be that my repair and re-pitch of the props is marginally over pitch....... more on this in due course.
The “up and onto the plane” is smooth and faster than pre refit. Gear change smooth and straightforward. I used full trim tab to get up and onto the plane most effectively but that is reasonable with a surface drive installation.
Your points about clean props and stern gear is completely correct, as is the EGT being an excellent indicator of all that is well or not well with the engines at any given speed...... hence my desire to be able to see that info !
 
Boatbore said:
If the cc improves that further then that will be worth writing up on here and I will do that in due course.
Click to expand...
I for one am looking forward to hearing about the results with/without CC in exactly comparable conditions, thanks in advance for posting your findings! :encouragement:

Ref. max rpm, according to an old Yanmar datasheet which I have in my files (and which I can send you, if you wish), actually it's 3300 for the 420hp flavor of their 6LY engine...
 
I,d be happy if BB s boat has matched ( well near enough ) the build data sheet after all theses years , at 3200 rpm .
There’s some tinternet chat about reliable rpm guages with the 5.8 L Yanmars .
Are those rpms guages or something from a screen via a nmea widget ? Or better have the engines ( difficult in the packed ER while running) been gunned ?
Just trying to get an accurate handle on the real rpms .Where the 3200 has come from .
Indeed there should be a plate on the engines with the “rated “ rpm as MapishM says 3300 .

How ever stuff like dirty / fouled airside intercooler s etc can take a bit out possibly or as said throttle cable issues for the last few % .
Anyhow because of the ambiguity of the rpm reading and the apparent matching the build data then I would not worry .

It’s just a case of settling for a cruise , Infact two , fast cruise and normal .
Fast in my book as fast as you want rpm them and stay within a notional engine longevity zone , from a EGT pov , which is the point of the thread ,
A very sensible upgrade indeed .
It’s just a case of finding and benchmarking the downstream EGTs , with other 5.8 L performance Yammers 370 / 420 / 440

FWIW I try and keep my EGTs south of 600 degrees downstream anywhere between 550 - 600 - different engines though different circumstances.I may do a short burst over 600 say 625 ish if somebody is 8issi g me off and want to blast them off .:) boys toys after all :)
How ever we also have “ load “ with the MMDS and I just stick em on 80% .
So use a combo of load and EGTs , There is a almost direct linear relationship between the two so you could use EGT,s if you know the calibration to set around 80 % ish load , for sustained long distance cruising 77-84 % ish ballpark.
My engines are 2003 and get a fresh correct spec oil change every year . Do about 80 hrs / year .

Here a quite recent article about Yanmar EGTs and note Tony Athens post — a respected marine engine guy from Seaboard Marine
https://www.sbmar.com/community/topic/interpreting-yanmar-egt/

Just to be clear not a big believer in X wot rpm less y % = cruise .
Or x wot minus 3/400rpm = cruise .

It’s your EGTs lads —— that you should set your speed (s) at in a planing boat .
Speed varies depending on sterngear hygiene and how much Lard you have accumulated.
 
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With a 370 the guys getting @2750/2800 rpm 925 F which is 496 C . Downstream.
So yours are 420 s same block ,
Extrapolating if your WOT is 3200 As is now - clean bum and gear , then I think 550 / 570 C is a good zone to be in .
So , s there a bit of headroom on the 2750/2800- to get the 496 up into 550 / 570 territory.
Estimate 2950 rpm / 2900 rpm
However your 420,s May produce more heat than the 370,s at 2750/ 2800 rpm and allready be in the 550/570 zone ?

Interesting to really find out when it’s up and working the EGT instrument s
Hope it all works out and ps keep us posted .:encouragement:
 
PF

what does downstream mean? Is it that the probe is AFTER the turbo?
Where are the probes on your MAN engines? before or after?
and how far back (well, cannot be that far back as you have the elbow and then the mixer at the end of it...)

I'm asking as the placement of the probe affects a lot the temps you register.

From my car modding days, they wanted it before the turbo but they were registering (iirc) 900+C there on WOT on the rolling road

cheers

V.
 
vas said:
PF

what does downstream mean? Is it that the probe is AFTER the turbo?
Where are the probes on your MAN engines? before or after?
and how far back (well, cannot be that far back as you have the elbow and then the mixer at the end of it...)

I'm asking as the placement of the probe affects a lot the temps you register.

From my car modding days, they wanted it before the turbo but they were registering (iirc) 900+C there on WOT on the rolling road

cheers

V.
Click to expand...

Downstream means after the turbo - sorry using constant terminology with Seaboard Marine .
EGT s sensors on my MANs are after / downstream.

We have had the manifold off , it’s a water cooled from the closed side . 6 into 1 .Theres no sign of any sensors or any other electrical stuff .

After the turbo there’s a short pipe then elbow then the exhaust riser .The first water injection point for the raw to start cooling is quite a way away from the elbow .
The turbo casing ,it’s connecting pipe and the elbow are all closed circuit cooled .

Exhaust pipe work is metal a short ish run to underwater boxes .
There’s a fart pipe that has its own water supply from one cooler ( oil coolers ) to the transom.
At low rpm tick over this carries all the gas .
As the rpm and speed increases along with the noise then the underwater water exhaust s proportionally take over .Of course the water pump is going full chat and dumping / cooling the risers to the existing boxes .
Each engine will have its own EGTs but loosely based on correct cylinder temps / pressures for the correct burn of the fuel to minimise sooting and maximise piston ring seal .
Because of the far higher pressure in a diesel head the rings are loose at low temps and need high temps to seal properly- expand etc to fit .
Hence diesel rattle when cold start up .
It’s a fine line - get too hot - excess EGT from dirty props / overloading - then the valves especially the exhaust valve suffer 1 st - hence my link ^^^^ - just happened to be a Yanmar 420/440 .

Petrols don,t suffer from poor cold fitting rings or excessive cylinder temps / pressure that compressing oil to ignite needs .

A simple downstream EGT sensor will help the boat operator get a handle on what’s going on - relative.
Without the hassle / complicated individual or upstream potentially fractures knackering the turbo .
If you run a performance oriented boat it more important you know how far to push it .imho

https://imgur.com/a/gQq9E
 
All really helpful thank you. Especially Porto and Vas for their details and diligence. I will keep you posted.

FWIW I agree with Porto re revs. The counters are not accurate to an nth, so I will be quite happy if all 3 little monsters run roughly to the same parameters after all this time. Things like dirty filters is t really an issue as all has been replaced..... basically every hose, valve, anode, filter etc has been replaced with new, and all ancillary parts reconditioned (turbo, starter motor, alternator, raw water pump, oil cooler, heat exchanger, charge air cooler etc)...... so they’re old engines, but running pretty much on spec. On the bench dyno they did exactly as they’re meant to !

I will report back on EGT project. I am keen to try and find the perfect solution but may settle for the fudge as per Vas’s excellent research! Thank you for that !

And I will have reasonably accurate before and after WOT figs with Andy without CC..... so that will also be interesting.
 
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