Perkins HT6-354 (145HP) fuel consumption.

[seamaster30]

Hi, I have searched the internet, but without luck (OK - I know they are old)
I would like to how much fuel my engines use per hour throughout the rev range.
I have logged my speed at 1000 rpm intervals, and would like to know the costs and range at different speeds.
It's a twin engine installation in a semi displacement cruiser.
It tops out at 16 knots (SOG) at 2500rpm and reaches 13 knots at 2200rpm max cruising speed.

Anyone have the fuel/power curve data for these engines?

 

[Andrew_Fanner]

I dont have the curve or anything like that, but at river tickover its betweem 1/2 and 1 gph depending on yuor tickover settings as much as anything else. At full chat its about 8 gph. This is in a Coronet Oceanfarer 32 on V drives.

Hope this is of any help at all.

 

[seamaster30]

Thanks for that - I had seen figures of 1GPH (per engine) at 1200rpm (my tickover is around 800 when warm) to 7GPH at 2400rpm so that seems to fit.
My tests with speed per 1000rpm seem to indicate the most economical progress is at 1200rpm which is about 7.5 knots.
After that it climbs quite steeply, then flattens out at the cruising rpm of 2200rpm when she is doing about 13 knots.
My 'very basic' measurements also show a 'Rev's per Knot' (no idea how valid a measurment this is /forums/images/graemlins/smile.gif) of 163 at 1200rpm and 169 at 2200rpm in the space between it climbs to 190 which I guess is the least economical.

 

[Andrew_Fanner]

Your S/D cruiser will have a pretty much straight line ratio between revs and knots until you reach hull speed, at which it goes all pear shaped. Being SD when you get over the hump you will get a meaningful proportional change again, but not while going up the bow wave, big throttle movement and lots of noise but not much change in speed!

Per the (dodgy) rev counters tickover is about 650rpm, which is fine going with the stream, not enough at times for serious steerage way but then I drive on the sticks if I need to be precise, otherwise the speed limit is breahced too far! Upstream is more likely to be 1200 or so rpm giving 4-5 knots over the ground

 

[seamaster30]

I have put my data into a graph, and it shows exactly what you say - straight line up to around 7.5 knots, then the hump, and then over the hump at 2200 rpm - I think I have bigger props than you - 800rpm gives 5.5 knots and 1200rpm reaches just about 7.5 knots.
I think the actual consumption is based around power used rather than just the rpm, but I have a reasonable idea on costs now.
When I service the engines, I will look at the throttle linkages (dual helm) as I am not quite happy with the settings, and I also want to reduce my tickover a bit too.

 

[forgotmyfrekinuserid]

Off at a tangent...does anyone know the consumption a Volvo an MD7A...?

 

[Andrew_Fanner]

Must 'fess I have no clue about my prop size, but my V boxes will mop up some grunt, up to 20% or so:-(.

Need to find an expert who likes to be paid in beer for advice and support when I get down to the boat at Easter, high time I sorted out a smokey engine, and indeed got it to turn over and start!

 

[seamaster30]

You won't sort out a smokey 6-354 - that's what they do /forums/images/graemlins/smile.gif
Mine start up smokey and clean up nicely while on a reasonable run, but the smoke returns very quickly at tickover speeds - from what I understand it's the norm for these engines and you are unlikely to stop it.

 

[Andrew_Fanner]

True, but this is acrid white/grey clouds, probably something horribly wrong with overfuelling or bady pump or iff cylinder...

I need to try cracking open a fule pipe to each cylinder in turn to check for duff one. Should not be the injectors as they were all done <2 years ago. Having said that, I guess I may have put them back wrong as they were done to cure smoking and didn't really.