Cummins in a ferd (let the hate begin)

[Eddyj]

It looks like I am the proud new owner of a 1999 F550. It has an auto and a high mileage 7.3
I'm not really looking to dump a bunch of cash in a abused 7.3 and thinking about doing a swap.
Anyone have any first hand experience?

Also any meme's about mopar or dodges sucking, invisible trailers, or fords sucking are welcome. Feel free to derail or talk about anyone who drives a different brand of truck than you their sexual preference.

 

[Zjman]

How many miles on the old 7.3. Don't bail on the old girl yet, they're a cheap hooker that will surprise ya with a little cash


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[lowbudgetjunk]

How many miles on the old 7.3. Don't bail on the old girl yet, they're a cheap hooker that will surprise ya with a little cash


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The hooker will surprise ya? Like with herpes?

Eddie knows Cummins. He also just wants his truck not to fall apart around his engine/tranny

 

[Beerj]

I support that swap. Hate to see someone get hurt.

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[Bronco72]

I put a 12v in a 04 i thank we ruint both trucks. The one the moter came out of and the one we put it in. We bought the conversion parts and it did fit and run really good. That toqure shift never has liked that cummins. We used a sct tuner to tune the trans. Honestly we probly had 25 custom tunes wrote for that white pice of ****. Never could get it to shift right. We just got it to were you can live with it. Still ended up putting a trans in it in less then a year. New one is still odd. Idk how that 4 speed auto would do. But id never do another one in a auto truck. And the damn truck has some odd vibrations and is very loud in the cab. We has to change the gov spring in the pump to get any speed out of the truck. I than 71 or 72 is all it woud do with a stock gov spring and it 3:73's that 550 proby wouldnt brake 50 stock and 70 with the rpm's turned up. At 80 you can not hold a conversation in the cab comfortably. It was a king ranch so it had nice interior. Honestly it was a better truck even with that junk ass 6.0. Maybe a 24v or the newer common rail **** would be better but that **** is expensive. We swapped injectors and turbo also just to get some power back. That stock 12 felt like a 4 cyl in that truck compared to the stock 6.0 that i pulled out. But on the flip side it is very reliable now and gets 19 mpg with that old fart drivin it like he is mad at it everyday

 

[Bronco72]

The only pic i have of it. Sadly that cummins looked right at home in there when it was all done

 

[halcat]

Carry on guys, I'm listening. I have a 05 f 550 4x4 with 112 k miles and had three 6.0 's. I had a thread about this a while back and everybody talked e out of it.

 

[RustyC]

I think a large part of the decision to swap would be transmission choice. Both the 5.9 and 7.3 are great engines. The 7.3 has the displacement but adds electronic components. The 5.9 can get had in a all mechanical version (which I would guess is why Ed is attracted to it) with less failure points.
I'm a heavy equipment diesel tech by trade and honestly I see machines that are down due to components failing that may not be 100% necessary to operate the machine. Sensors, relays, connections etc.
I fully agree with the reliability of a all mechanical 5.9 P pump and manual transmission. HELL if you can hook a mule to is and roll start it you good to go if needed.

The 1999 F550 7.3 is a forged rod motor which is a plus. Standard 7.3 electronics and turbo etc. The transmission is what would concern me more. 4R100 are not known to handle the power beyond the stock 250hp without upgrades. Mostly converter issues and or heat.

I would check blow by or compression on the 7.3 and make a decision from there. If it checks good. A re-man HUEI pump and injectors and oil changes keep them very reliable. Add a bluetooth obdII adapter and the Torque or Garage Pro apps on your phone and you can check and clear codes whenever you would need to.

All this coming from a guy who owns a 2002 F250 cc4x4 with a 7.3 and auto. The only thing I would consider changing about my truck is to a ZF6 manual trans or a ALL mechanical 5.9 , ZF6, np205 combo.

 

[gottagofast]

I almost did it to my 99.... I still think I maybe should have.... from what I hear 3.55 or 3.31 gears are a must....

Currently strongly considering a cummins for my square body GMC build

 

[Eddyj]

Mileage is 300xxx on 7.3. The last 4 years it has not been maintained well

 

[Sawzall]

from what I hear 3.55 or 3.31 gears are a must....

I am running 4.10 gears and a NV4500 in my Chevy conversion with 245/19.5 tires which are roughly 33" diameter. The 4.10s work great for my 24,000 total weight but a 6 speed would have better gear splits for heavy towing.

 

[Hillbilly Beast]

I put a 12v in a 04 i thank we ruint both trucks. The one the moter came out of and the one we put it in. We bought the conversion parts and it did fit and run really good. That toqure shift never has liked that cummins. We used a sct tuner to tune the trans. Honestly we probly had 25 custom tunes wrote for that white pice of ****. Never could get it to shift right. We just got it to were you can live with it. Still ended up putting a trans in it in less then a year. New one is still odd. Idk how that 4 speed auto would do. But id never do another one in a auto truck. And the damn truck has some odd vibrations and is very loud in the cab. We has to change the gov spring in the pump to get any speed out of the truck. I than 71 or 72 is all it woud do with a stock gov spring and it 3:73's that 550 proby wouldnt brake 50 stock and 70 with the rpm's turned up. At 80 you can not hold a conversation in the cab comfortably. It was a king ranch so it had nice interior. Honestly it was a better truck even with that junk ass 6.0. Maybe a 24v or the newer common rail **** would be better but that **** is expensive. We swapped injectors and turbo also just to get some power back. That stock 12 felt like a 4 cyl in that truck compared to the stock 6.0 that i pulled out. But on the flip side it is very reliable now and gets 19 mpg with that old fart drivin it like he is mad at it everyday

Ahhh good times. That old fart has it in Drive and standin on the accelerator before the starter disengages.

 

[Eddyj]

Pics of truck that appears to be very similar.

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[truckbroke]

Why in absolute hell would you not just drive the 7.3 go ahead a pickup a descent used one or new long block so when yours dies just swap and go. Seems like your really just going to waste alot of money and ruin a truck doing the Cummins swap.

 

[Eddyj]

To be honest I've been wanting a 450 or 550 for a couple years. Almost bought a kodiak last year. I don't like the extra attention it gets while pulling (DOT) and haven't found a 550 without a flatbed.

This I love the bed. It has a extra 70 gallon tank, airride, 19.5 rims, and was bought cheap.


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[TBItoy]

Why in absolute hell would you not just drive the 7.3 go ahead a pickup a descent used one or new long block so when yours dies just swap and go. Seems like your really just going to waste alot of money and ruin a truck doing the Cummins swap.

That's kinda my thinking.

I could see if it was a 6.0 truck, or a gas burner or something. But I don't see what would be the possible gain of a Cummins vs bolting in a reman 7.3 (after the original 7.3 fails)

 

[gottagofast]

I fn HATE my 7.3.... I'm also sad to say that it pulled big weight (30k plus) better before I did the ZF6 swap....
Used to be a rocketship.... now it's comparatively a slug.

The body and chassis are great but the 7.3 leaves a lot to be desired. IMHO of course

That said.... as stated above.... do a compression test.... if it's good you can get the 7.3 running good for a LOT LOT LOT less than a cummins swap and most people seem to have WAY better luck than me with these engines.

 

[bbone]

Just my .02:

-your are making a simple solution very difficult. give the 7.3 some love, tuning and turbo mods...rock out
-you have a good platform for towing...the gears, axles, tires and fuel capacity are all positives.

 

[broncomike]

I have a 96 Dodge that when the truck falls apart I,m think about finding a f250 to do the same thing.

 

[ridered3]

That's a neat bed! What gears are in the F550?