Volvo D12 series

[jfm]

Yup VP have ploughed there own furrow with unit injectors , the same principle s modes of failure apply , just the terminology.
Unit injectors that VP use have smaller cannuli and multiple events ( like CR ) .
Perhsps the 775 Hp ( D12 800 that Novanta ^^^ reffering to is just a step too far with UI pressure / tech ? In every day life in a boat susceptible to $hitty fuel ?
Agree the 715 is good un , buts that’s not what Novanta is asking .
CR pressure is from 1500 to 3000 psi , VP UI injector Pressure is 2500 psi ,
But as said there are a lot out there and folks needs to do there own DD

Have you any thoughts on VP UI injector failure btw ?

@ JRudge — re post # 18 , nah that’s a bit harsh , just shooting the breeze , where did the make of my current boat get a mention in this thread ?
D12 is a common engine a popular one in the 50 ftr / 60 ftr+ , this should develope be an interesting thread , let’s stick to the subject D12 .
Actually it would imho be nice to de drill a bit deeper in the world of UI.s ( in a nice friendly manor ps ) — but no worries if folks have no appetite , It is winter and the nights are long

Porto you must dream all of this stuff or something. 3000psi for CR sytems? Are you kidding? You're a whole order of magnitude incorrect. And VP ploughing their own furrow? Pretty much all the big makers have non CR unit injection engines in their line up. Obviously the trend/direction is to CR because of emissions regs, but to say VP ploughed their own furrow with non-CR fuel pressurisation is just nonsense when the other majors have made unit injected engines for years.

 

[Portofino]

Porto you must dream all of this stuff or something. 3000psi for CR sytems? Are you kidding? You're a whole order of magnitude incorrect. And VP ploughing their own furrow? Pretty much all the big makers have non CR unit injection engines in their line up. Obviously the trend/direction is to CR because of emissions regs, but to say VP ploughed their own furrow with non-CR fuel pressurisation is just nonsense when the other majors have made unit injected engines for years.

Bar not psi , my mistake . Senior moment recalling - here’s the source .
http://nordicblog.volvopenta.com/unit-injector-vs-common-rail-marine-vessel-industry/
I mean,t ploughed there own furrow with the Delphi units made for them ,to handle high pressures through small cannuli , apparently the early Delphi units for VP had a ball that corroded , I think this was upgraded eventually , after a huge number of failed injectiors on VP stuff .

I think VP still use a copper sealing ring ,while others have moved away

Others use Bosch units which seem to be less problematic -
Rarther than nick pic
Do you acknowledge a VP injector problem with the Delphi units ?

You don,t find much stuff about Bosch injector s
Here’s a thread from here ,there are loads on VP injector failure - take you pick ,this is boaty —- there’s loads from the truck guys as well
http://www.ybw.com/forums/archive/index.php/t-161523.html

 

[Portofino]

Looks here as if the EUI may have even higher pressures ( numbers not relevant ) than CR .

https://www.dieselnet.com/tech/diesel_fi_ui.php

So by “ ploughing there own furrow “ with Delphi EUI,s multiple events with smaller cannuli if that’s so , then along with the leaky injector cups that’s a plausible answer to the 775 D800, injector failure .

The part numbers for the Delphi units are all different too for the various D12 derivatives , that in it’s self opens up the possibility that they are designed for different pressures , my monies on the greater the Hp the greater the P . Less robust with $hit fuel ??

I wonder VP they have resisted to go down the CR route with the D12 ?
While the Competition went down the CR route years ago with seemingly no hassle Bosch re injector s ?

 

[MapisM]

I've had 4 of these, 715 and 775

J, do you remember what max speed your two Sq58 were capable of, respectively with the first vs. the latter?

 

[jfm]

J, do you remember what max speed your two Sq58 were capable of, respectively with the first vs. the latter?

yep. When both brand new in cool U.K., loaded with tender and about half fluids, 33.5-34kts. You never get perfect accuracy because ok uk tides. I never got any meaningful difference, even a knot, between 715 and 775 and there was no significant spec difference to cause any weight difference afaik. In warmer med and with a bit more gear loaded both were consistent 31.5-32, with some but not much fouling. Fwiw there is also no measurable diffference between cat c32 in the 1572 non acert version and the 1622 acert

 

[MapisM]

Interesting, thanks.
That confirms my doubts on the test made by MBY back in 2001, where they achieved 33.3kts with the 800hp Cat 3406, BUT with the engines spinning at 100rpm above their max of 2300.
In other words, it's reasonable to guess that with longer props the boat could have made a tad more than 34kts, with the Cats.
Regardless, a good performance indeed - particularly with the 715.

Your final sentence is making me curious also about the 78.
I suppose that also between M1 and M2 the specs/weight differences were not so relevant?