Big Red Pile 91 W350 Build Thread

[ellis93]

Be forewarned that it takes a while for the engine to get to normal operating temp.... This does however get rid of the excessive temp spike and gauge swing. I also seem to lose that pressure buildup that happens between startup and the thermo opening. Hope it helps

[DodgeFreak]

Dads truck will do that too. It doesn't bother us as long as it blows heat and doesn't peg it lol. You thinking you'll need to rebuild your engine?? Is there blow by?

What if you cut one bleed hole and tacked the other shut that way it will still bleed coolant and air but won't circulate as much.

[bgilbert]

I vote put the old stat back in! Or new parts store unit! I'm done with Cummins stats myself! lol

[CumminsPower59]

If I can find it...I may have pitched it

[Art]

I have seen several trucks do that with the stock thermostat.

Cummins has another thermostat available that doesn't do that (has less hysterisis) , but they say it may cause slightly longer warm-up times. I think it must not close off as well when the thermostat is closed.

[CumminsPower59]

Ok, more nonsense jibberish.

At 55mph, these figures are what the gauges are giving me.

In fourth gear, 1700 rpms, 675 degrees, 2-3 psi.

In fifth gear, 1300 rpms, 575 degrees, 0-1 psi.

Half of my commute is two lane, the other is 65mph interstate, then about two miles of city.

What say you all for best mpg's and what not?

[RCCUMMINS89]

I'd do 5th gear at 1600 rpms for best economy.

[CumminsPower59]

Thats easy enough at interstate speeds, but to turn those rpms at 55mph, I can't use fifth...

[RCCUMMINS89]

Run the lowest sustainable rpm that isn't lugging the motor. That can be hard to do at times.... so I try to explain it like this.

If in 5th gear you are using more throttle than you would be in 4th.... just use 4th.

[CumminsPower59]

What is your definition of lugging? I've heard different numbers, i.e., 1500 etc...

[CumminsPower59]

It'll run happy as can be with just my foot resting on the go pedal at 55mph in fifth, but that's the million dollar question, is 1300rpms too low for sustained periods...

[RCCUMMINS89]

No.... there is no given rpm that is lugging it. For example, in 2nd gear, 1000 rpms is plenty and the engine is not lugging at all.

Oh, and I sometimes run 25 mph in 4th...can't do below 45 in 5th though.

[CumminsPower59]

If I had a Getrag, I doubt I would be running 5th, but the NV doesn't growl like a Getrag does...we for me anyways

I usually drive my truck as Ellis calls it "pa pa" style, but I still flog it from time to time...

But since I've rebuilt the NV, it doesn't shift as "smooth" as a proper rebuilt or non molested one shifts, seems to catch and then go into gear...

[RCCUMMINS89]

Clutch throw correct still? That's how mine shifts and my rod and pedal are CRAZY worn.

[CumminsPower59]

Hell, I dunno. Nothing was worn when I converted my pile, most parts were near new. I didnt know if the 1st gen hydro's didnt have enough throw for the NV...or if I should be using 2nd gen hydro's?