temp boost guage

[Dominic Maionchi]

I would like to install your SMX Marine Boost / Pyro (EGT) Turbocator Gauge Kit on my yanmar 4jh3-hte.

questions before i order:

1. please confirm that I can install on this engine.

2. where do i install the pyrometer? do i drill and tap the stock exhaust mixing elbow? if so is there a preferred location?

3. where do i install the boost sensor? intake manifold? is there a place i can install it without removing the intake manifold?

4. if i order extra lengths of wiring and tube, please confim that i can trim lenght to fit.

Topic

[Tony Athens]

Keep the diameter as large as possible– Drop the pitch.

Tony

[Dominic Maionchi]

ok im starting to understand

ill order new blades. ill get flexofolds recommendation, even though they recommended this size in the first place.

off the top of your head, do you think its better to adjust by making the diameter of the prop smaller, or changing the pitch?

i’ve read that changing the pitch makes the prop less efficient.

[Tony Athens]

You just now moved the goal post another 300 RPM.. That’s a big move..

Prop down to get your 3800+… Yanmar designed to engine to do that.

Tony

[Dominic Maionchi]

about 1.5 gallons per hour.

yes im only using about 30 hp.

So I’m not hurting the engine cruising at 2500 to 2800 rpm depending on sea state, even though i’m overpropped across all rpms, right?

i can change the 4 blades on the propeller hub with blades with less pitch to get to 3850 at wot. what advantage would i get in doing so?

dom

[Tony Athens]

DM,

#1————Agree with ROB–Yes, he said based on your “numbers”, you are over propped across the board per Yanmar requirements.. Per Yanmar, you should reach the minimum rated RPM of 3800..

#2—I will add an IMO though.. Yes, on paper you are 300 RPM over propped on a 3800 RPM diesel that is conservatively rated (about 50 HP per liter on a turboed/aftercooled engine that is very well made).. But, you are happy at 1000 RPM off the top.. Where does that put you as to load ??– IMO, NO ISSUES as you are probably only asking about 20-25 HP max from the engine at cruise..

What do you think your burn per hour at 2500 RPM in GPH? Any idea?

Tony

[Rob Schepis]

Dominic Maionchi wrote:

do you agree with rob that as long as i cruise at 2500 at 8 knits im not damaging the engine through overload?

Where did you get that? Re-read my replies.

[Dominic Maionchi]

prop

tony
i ordered the pyro/boost guage last night.

any thoughts on the prop sizing?

do you agree with rob that as long as i cruise at 2500 at 8 knits im not damaging the engine through overload?

dom

[Rob Schepis]

t-stat opening temp = putting enough load on the engine that it comes up to and maintains normal operating temperature.

[Dominic Maionchi]

i dont understand.

you wrote: but if you stated that you cruise the engine just over thermostat opening temperature, something like 1,200 or so then you’d probably be safe as is.

I cruise at 2500 rpm as per the guage at about 8 knots. How does this equate to therostat opening temperature?

[Rob Schepis]

Yes, overpropped across all rpms but if you stated that you cruise the engine just over thermostat opening temperature, something like 1,200 or so then you’d probably be safe as is. But for sure check the tach 100% and then re-evaluate your current propping.

[Dominic Maionchi]

accuracy of tack

im going to check ccuracy of tach again. my eyesight may have failed me in the bilge. it must be 50 rpm off across the range. two of the readongs must be mistakes. so at 2500 on the tach must be 2450.

so i can do approximate hull speed at 2500. However, after reading the articles on overpropping if the engine is overloaded at wide open throttle wouldnt it be over propped across all rpms?

dom

[Dominic Maionchi]

2500 rpm at 8-8.5 knots

i posted the accuracy results above

[Rob Schepis]

As to the propping, Tony already asked this but you have not answered:

Assuming your tach is accurate, at what RPM do you cruise at in average sea conditions? What is the average vessel speed at that cruise RPM?

[Dominic Maionchi]

great. thank you. ill order the guage tonight on your website.

any thoughts on the prop?

[Tony Athens]

Look at the pics.. The pyro probe is easy–Pull that plug and drill and tap it 1/8″ NPT..

Boost— Can’t tell for sure it these spots go into the intake manifold.. If so, either one in fine–Pull the plug and drill & tap 1/8″ NPT..

Tony

[Dominic Maionchi]

overloaded?

is the prop overloading the engine? i have a 4 blade folding flexofold prop. if its oberloaded can i ask flexofold for different pitch blades?

where do i install the boost and temperature sensors?

thanks

dom

[Dominic Maionchi]

accuracy of rpm

Instrument tested with LED instrument on cranck

1000 1030
1500 1350
2000 1985
2500 2350
3500 3450

seems accurate

[Dominic Maionchi]

testing results

Here are the results:

Wide open throttle in neutral: 4,400 rpm

Wide open throttle in gear: 3,500 rpm

Engine rating: Maximum output 100 hp at 3800 rpm (see attached for Yanmar 4jh3-hte)
https://www.simplicity-marine.com/pdf/Yanmar/JH.pdf

Test results with clean bottom.

RPM Speed over Ground measured by GPS

1500 5.9
1750 6.4
2000 7.0
2250 7.3
2500 8.7
2750 9.1
3000 9.4 with very light white smoke
3250 9.7 with light to moderate white/grey smoke
3500 9.7 with moderate darker white/grey smoke smoke

[Dominic Maionchi]

pictures

mixing elbow looks like it has a plug in it. 3rd picture

exhaust manifold looks like it has a plug on it. 4th picture.

intake manifold looks like it has a plug on it. 6th picture

can i use any of these?

if so how do i go from metric to your 1/8 npt?

dom

[Tony Athens]

Are you sure the “white smoke” in not steam?

Assuming your tach is accurate, at what RPM do you cruise at in average sea conditions? What is the average vessel speed at that cruise RPM?

When engine is is “stone cold and has not been run for a few days, how easy does it start?

Tony

[Author]

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