Skip to main content ↑ ↓
Topic: Fuel Cooler on U300 (Read 1432 times) previous topic - next topic

Re: Fuel Cooler on U300

Reply #20 –
My VMSPC indicates that my fuel temps run in the high 130's in the hot summer weather. Its on my list of To
Do's.

Re: Fuel Cooler on U300

Reply #21 –
Quote from: Mark Blain –
Quick question, should I consider this modification on our 45' 2010 ISM500?

Thanks, Mark

On almost all diesels, you might want to monitor the fuel temp but only a Detroit runs the fuel supply and the return in interior cylinder head passages. This means it gets up to almost coolant temp before it supplies the injector/pump and then heads back to the fuel tank.

Mechanical Cummins and CATs use an injection pump that is mounted on the outside of the block so while they do pick up some heat from the excess fuel from the injectors, it's not as much as the Detroit 2-cycle. Later diesels have a common rail injection and will pick up even less heat before the excess fuel heads back to the tank.

Big rig fuel tanks are mounted out in the open and have plenty of air flow to keep the fuel pretty cool.

Pierce

Re: Fuel Cooler on U300

Reply #22 –
Quote from: wolfe10 –
Somewhere in the back of my mind (a fragile place) I recall that most HP and consumptions specs for engines are run at fuel temperatures of 80 degrees F. 
And, as Dave said, hotter is worse from a number of aspects...
I saw an EMD calibration sheet used to check the HP on loco engines.  Part of it was adjusting for fuel temperature.  The slope of the line was linear and it was 1% decrease in power for every increase of 10F.  The cross-over was at 70F but I think that's just arbitrary for how they had their reference engine set-up.  I think this is universal for diesel fuel and not engine specific but I really don't know.  I guess I don't really know the physics of why fuel temperature would affect power.

Re: Fuel Cooler on U300

Reply #23 –
Quote from: Mark Blain –
Thanks Brett, I found it finally and of course, right after I asked what it meant. As a newbie, this forum is a comprehensive course in itself. And, it's addictive, I can't pull myself away from it.
Take care, Mark

Mark, on your rig keep a close eye on the CAC unit. It looks like radiator on the back of your rig (the big one). These are known on the Nimbus 07-11 to split in the seams and thus loosing your turbo pressure. The end caps of the unit are aluminum like the core and seam splits are very common. The new units are steel ends with aluminum core with steel rods across the front and back to hold the ends in solid. We had to replace our on the 07 Nimbus. The change came to these units late 2012. Also, the mounting brackets for the transmission cooler also there will tend to break from road fatigue and rattle. The rattle is caused when the transmission cooler pounds against the CAC unit.
Bob

Re: Fuel Cooler on U300

Reply #24 –
yes, that cooler does cause a problem when bolts come loose and bang into CAC. I had 3 holes in CAC from that so had to repair them so boost came back. Bad mounting design with Rad, CAC and cooler that DOES need to be checked now and again or else!! I am a Scrooge so fixed it rather than buy a new one. Not for the faint of heart to do but it has been good now over 2 yrs and saved mega coach Bucks.
JohnH

Re: Fuel Cooler on U300

Reply #25 –
Wonder if they heat the fuel that hot to start it with normal heating less.

Bunker fuel has 155,000 BTUs per gallon compared to about 134,000 for diesel.

Locomotives used to use bunker fuel but smog regulations made them change over. Remember how they smoked a few years ago.

Pierce

Re: Fuel Cooler on U300

Reply #26 –
Thanks Bob,
Really good to know. I'll add this to the check list, would have been nice to have gotten a note from FT giving me a head's up.
Regards, Mark
 

Re: Fuel Cooler on U300

Reply #27 –
2-stroke oil helps lubing injectors.  pc