98 5.9l Cummins 12V vs. 99 7.3l Powerstroke

[JSUnlimited]

I've read up on the KDP issue with the Cummins, and am aware of the 5 speed Dodge stick trani issues.

Best Rgds, D.

I think you have just answered your own question.

 

[RobertN]

Totally have to disagree, as in above post.

The 4x4 3/4 and 1 ton Twin ibeam are not a very good front end. They are a weaker front end to begin with; Dana 50 as compared to the standard Dana 60 up front.

The Twin Ibeam rides marginally better than the solid axle. that is about it.

I never busted a solid axle, but did a job on an inner ujoint on a twin Ibeam. The ujoint did not fail, the end of the axle shaft, that hold the ujoint popped. During pretty easy 4 wheelin, something a typical truck would see on a ranch or weekend hunting.

The Twin I-beam setups are saggy front ends, with resultant tire wear. After having had it, I notice it all the time in the older Fords. I had to fix mine twice(new springs, and a couple bushings) before I switched out the axle. Looking at the front of the trucks, you can see the tires leaning in at the top. Mine was stock too; no lift kits or anything...

The leaf springs sag. The Twin I-beam pivots in the center of the truck, so the axles moves up and down in an arc, not primarily straight up and down like a straight axle. The leafs just do not wear well in that situation.

It is easy to fix; new springs are not too hard to put in. But, it will wear again.

After switching to a straight axle, the first thing I found is the truck turned significantly tighter. Since mine was a long bed xcab, that really made a difference to me.

In the end, my second F250, after switching to a Dana 60 straight axle:
1 - turned much tighter
2 - springs quit sagging
3 - was a much stronger beefier axle
4 - tires wore more better
5 - Handled load much better, with 11' cabover camper, and/or trailer or bed full of oak firewood.

Both of my F250's 4x4 were gas; I'd hate to put a diesel on top of that twin-ibeam. Even with an extra spring in the pack, it would wear worse from the weight.

I like Ford trucks, even though I have a Dodge. Both of mine were good trucks, except that IFS front end.

The only way I would buy another F250 with twin ibeam is if the sale price was really cheap so I could spend the money saved on a replacement front axle. It is pretty easy to swap the axle, although a Dana 60 for one is pricey...

The "twin I-beam" front suspension has been a stalwart design and is TOUGH, especially true in the 4x2s.

 

[Egon]

The 4x4 3/4 and 1 ton Twin ibeam are not a very good front end. They are a weaker front end to begin with; Dana 50 as compared to the standard Dana 60 up front.

I'll second that. The twin I beams did not seem to hold up well on the working trucks I saw or drove.

 

[Diamondpilot]

I'll second that. The twin I beams did not seem to hold up well on the working trucks I saw or drove.

How long has it been since they used the Twin I Beam? I can not remember them in any trucks we have owned other than a 1986. All my Superdutys, a 99, 04, and a 06 all had solid front axle.

Chris

 

[RobertN]

My '80 an '89 had them. I know they went a few years still after my '89.

How long has it been since they used the Twin I Beam? I can not remember them in any trucks we have owned other than a 1986. All my Superdutys, a 99, 04, and a 06 all had solid front axle.

Chris

 

[om21braz]

I had a 94' F250 with the solid front axle and presently a 97HD (old body) with the IFS.

 

[RobertN]

It was optional. In '89 they came both ways. I think the straight axle was the super duty version.

I had a 94' F250 with the solid front axle and presently a 97HD (old body) with the IFS.

 

[flusher]

Thnx guys.... that is exactly the general feedback that I was looking for.

Specific points are well appreciated..... I hadn't considered that nuance for the Boat/Tow site before. Will get the tow rating from DC tomorrow, and will chase the F250 specs too.

I tend to think of checking consumables pricing for printers.... good point flusher ! I'd suspect the wear/tear (engine wise) pricing for the 7.3 will be higher. Flusher - did you conclude anything concerning annual mileage vs. payback on a diesel vs. gas ? Also, thnx too... I was scratching
my head late last night as to what the HPOP was on the 7.3l.

. D.

Yep, the HPOP provides high pressure oil to operate the injectors on the Ford 7.3L diesel.

My annual towing mileage is only 3000-4000 miles and the load (my parade tractors) ranges from 2500-4500 lb. So it's hard for me to justify the higher initial cost for a 3/4T or 1T pickup with a diesel engine. The fact that the Cummins engine can go 300K+ miles without major overhaul is not a big swinger in my case. After several months of juggling various tradeoffs, I'll go with a 2005 or 06 F250 with the 5.4L gas engine and a 10K bumper pull car hauler.

 

[ModMech]

The trucks I'm looking at are 2wd. While 4wd would be "nice to have" (for me), I prefer 2wd considering how long I hang onto vehicles.

I'm not a fan of 4x4 unless there is a BUSINESS NEED for it. Good.

Thnx for the detailed engine feedback ModMech - makes sense, as a medium duty engine, the 5.9 will have a lot more headroom in the design, if you really want to beat on it (performance wise).

They are both "medium duty" engines, but the B5.9L was designed from the beginning for BIG power in Marine and Industrial applications so the parts are already there for it. The 7.3L PSD is no slouch and can make upwards of 600 WHP, but at about double the cost per HP of the Cummins.

The only upgrades I'd likely do on either truck is better air filtration (if needed), and a freer flowing exhaust. The goal would be efficiency, and cooler running. Any harm (reliability wise) with these mods on the 7.3 ?

I wouldn't EVER mess with a factory air intake system. Getting even a very small amount of dirt into the engine will cause RAPID wear, something only racers don't give a rip about. If the airflow is "easier" or more free, so is the dirt flow, it really is that simple. There are significant gains to be made with mandrel bent CAC pipes and turbo down-tubes

Any "Injectors for Dummies"tm summary on comparing these 2 systems ? I have to admit to being ignorant (and a little confused, esp. re the PSD system - why have a 500psi oil requirement to operate a fuel injector ?).

Sure, this should be easy....

Cummins: Bosch IP, HIGHLY pressurized fuel is supplied ONLY during fuel injection (can be electrically controlled depending on year) by the IP using lobes like on a camshaft thru individual lines to individual injectors. When the line pressure exceedes the VOP (valve opening pressure) of the injector, fuel enters the combustion chamber. Advantages: Simple and well understood.

Ford: HEUI pump pressurizes engine OIL, fed to the injectors at 500-2500 PSI which are turned "on" allowing the HP oil to act on a piston inside the injector (hydraulic ram affect) forcing fuel stored in the injector body into the combusstion chamber. Advantages: Total control of fuel timing, quantiy and delivery profile from one combustion event to the next. Better performance and low emissions.

I'm wondering if the 7.3 HPOP is a dealer only item, couldn't find them at Advance Auto just now, sounds like these do go, and am trying to estimate cost.

They are READILY available in the aftermarket and cheaply. It would cost you more and take longer to change the electric fuel pump in most cars

I use Stanadyne Power Formula year round in my old Ag tractor (just to be kind), and would also use this on either truck.

Did I understand your post correctly - the Cummins fuel system is more sensitive to ULSD than the PSD ?

Thnx, Rgds, D.

I do NOT advocate any fuel addatives unless there is a specific problem (like algea) you are trying to deal with.

I can only say that the 7.3L PSD fuel system has been tested with ULSD and the new fuel will do no harm to the mechanical or electrical components of the system.

 

[ModMech]

How long has it been since they used the Twin I Beam? I can not remember them in any trucks we have owned other than a 1986. All my Superdutys, a 99, 04, and a 06 all had solid front axle.

Chris

That depends......

4x2 was 1997 for the SLA system and with 4x4 depending on GVW, 1999 for the twins.

The BIG advantage of twin I-beam is fewer wear parts over IFS while keeping the tire square to the road. After all, 99% of all 4x4s see very limited actual off-road use, those that do seem to see a LOT of off-road use Therefore, for most customers, on-road stability and ride quality is most important.

For the 4x2, they were a LOT more duarble than the SLA (automotive type) systems used by GM and Chrysler on "trucks" and "full size vans".