Detroit to Cummins

[Bandit102]

Well, its time to dump the detroit in favor of a N-14 Celect Plus. The N-14 is coming out of the same year Freightliner as the one the Detroit is coming out of. Anyone done a swap like this? Any suggestions?

[heavyhaulerss]

imo... you'll not get better fuel mileage with the cummins

[Bandit102]

Well, I'm not looking for better fuel milage. The Detroit did 5.5 anyway. I'm putting in a 13 double overdrive trans. so it may after all improve a bit anyway. I'm just after a dependable engine. My Detroit evidently has some issues with the block. It has blown 4 head gaskets in 200,000 miles. Last time, I majored the engine and it blew another one at 71,000 miles, so I'm through with it.

[heavyhaulerss]

no joke? wow. I dont blame ya. i would switch too. good luck..

[enobeenob]

I am getting 7.4 mpg with a 500hp N-14 Celect Plus with a 13spd and 3.43 rears.

I say that will beat any Detroit on Mpg.

[allan5oh]

It depends on the load, and how fast you're going. Basically how much horsepower you need to go down the road.

The engine that uses less fuel to make that same amount of horsepower, will get better MPG.

Saying that, I do think detroits are a little more efficient then n-14's

[Bandit102]

Yeah, my damn truck has 3.73 rears. So, I'm gonna try the double over 13 and who knows, I may have to slow down. Besides, 80mph just doesn't pay any more. It'll be damn nice just to be able to go down the road and not worry about how many months the damn engine is gonna hold together like I did with the Detroit. I've always liked the N-14 much better than the Detroit anyway. It'll do much better at a much lower rpm than that stinkin Detroit ever would.

[enobeenob]

It depends on the load, and how fast you're going. Basically how much horsepower you need to go down the road.

The engine that uses less fuel to make that same amount of horsepower, will get better MPG.

Saying that, I do think detroits are a little more efficient then n-14's

I doubt it, had a Detroit before in a Freightshaker, nothing but problems, blew a head gasket at 550,000 miles and got rid of it.

Best mpg was 6.7, doesn't compare to 7.4.

[pdm]

Just wondering how many total miles were on the detroit. & how the swap went & how its working, fuel mileage etc.

[heavyhaulerss]

I am getting 7.4 mpg with a 500hp N-14 Celect Plus with a 13spd and 3.43 rears.

bobtail mpg does not count.

[enobeenob]

I am getting 7.4 mpg with a 500hp N-14 Celect Plus with a 13spd and 3.43 rears.

bobtail mpg does not count.

I think not. I am talking about loaded mpg, 7000lbs to 44,000lbs loads. Actually mpg went up to 7.5 two weeks ago.

[bob h]

Well, its time to dump the detroit in favor of a N-14 Celect Plus. The N-14 is coming out of the same year Freightliner as the one the Detroit is coming out of. Anyone done a swap like this? Any suggestions?

this will not be a straight swap, the oem harness (cab bulkhead connector to ecm) will be quite different and you'll probably hope one came with the engine. the cab side of that oem harness (inside the cab to switches, etc) might be different as well (but, possibly not). The low pressure fuel system will require some modification, but that again will depend on what they give you with the n14... is the cummins dressed, what's on it (or not) air compressor, starter, ecm, etc??

[Bandit102]

Well, its not in yet, but ready to go in. I went ahead and majored the Cummins first. I bought the entire truck, Bob, so I have everything, harnesses, everything. The Cummins did not have Jakes, so I O/H a set that I had for an N-14 and put them on. I'll have to figure out the wiring there. The bulkhead connectors that come through the firewall in into the dash appear to be identical.

To answer another question posed, the Detroit had 980,000 with NO problems, then blew a head gasket. Replaced the head with a Detroit reman, lost the gasket again, replaced the gasket, lost it again. In majoring the engine, the counterbores are in poor shape and the block has a .013 sag in the middle and .007 with a jack under the middle. I knew it wasn't going to run as long as it did originally, but only 71,000 miles on the major and it did it again, so out with the Detroit and in with the Cummins...

[Bandit102]

bump

[Bandit102]

Well, I have about 10K on the Cummins 525hp N14 now. Sure makes that Detroit seem like a turd of an engine...I'll never have another one.

The swap went really well, actually. Fuel lines were a bit different in length, a/c lines are some different, due to the compressor mounting on opposite sides of the engine, but they did make the stretch. Had to take her in to the Cummins shop to have TPS wiring and Jake wiring changes made. Other than that, everything else was gravy.

[smith1979]

does anyone know how to check the flash codes on a 99 frieghtliner it dont have an engine override switch and that is how im used to checking them cause going down the road after bout 150 to 200 miles my oil pressure gauge will go to 20 psi and stay there stopped or moving and I was wanting to check the flash codes on it the truck has the ISM cummins in it

[Maniac]

In majoring the engine, the counterbores are in poor shape and the block has a .013 sag in the middle and .007 with a jack under the middle. I knew it wasn't going to run as long as it did originally, but only 71,000 miles on the major and it did it again, so out with the Detroit and in with the Cummins...

Never seen a Cat block do that, must be why the Cat engine weighs so much.............LOL

Glad to hear the swap went well

[Bandit102]

131,000 on the Cummins now. Man, she's a ground pounding son of a gun. That Detroit would never hold a candle to the Cummins. Now, in a 40 mph headwind pulling a 14 wide load, keeping 75 mph at 35 psi of manifold pressure (something the Detroit would have never dreamed of doing) this big Cummins will turn in 3.4 mpg! But other than that, about 6.2 is the average - which is some better than the Detroit.

I'll never have another green engine. Hell, them yellow motors aint so bad, for a rich man, I guess. Just can't figure how they sell them when a guy can have a Cummins.

[Windwalker]

Had an N-14+ in my truck too. Originally, I was getting 7.5 with 3:43 rears. Cummins sent me a recall to have the ECM reprogramed for less NO emissions. That dropped me down to 6.5. Rear end ratio has a whole lot to do with MPG. Had a CAT back in 2000 that got good fuel economy too. That ratio was also 3:43. But, I'll take a Cummins over a Detroit anyday. Just a better engine in general.

[heavyhaulerss]

DETROIT'S are better! put up your DUKE'S!