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".

 

[RobertN]

Are you referring to F150 with the coil springs?

I have never seen a F350 or F350 4x4 twin ibeam with leaf springs, that kept the tires square to the road. As I noted above, not the two I had. Have seen some that were not as bad, but not many.

Great trucks other than that though. I guess the rear tires stayed square to the road.

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.

 

[Dmace]

They are both "medium duty" engines

You should tell Ford you think their Powerstroke is a "medium duty" engine because even they don't think so and use the Cummins engine in their "medium duty" class 6 and 7 trucks. :laughing:

The Powerstroke is NOT a medium duty engine, and does NOT like much more then about 50% more HP at most. I've seen plenty of failures.

If the truck were to double as a daily driver then I would go for the Ford, more comfortable ride and larger, newer interior but if it's mainly a tow truck and work horse then Dodge Ram all the way.

 

[ModMech]

You should tell Ford you think their Powerstroke is a "medium duty" engine because even they don't think so and use the Cummins engine in their "medium duty" class 6 and 7 trucks. :laughing:

:laughing:

Really? Do you know WHY? Obviously not, or you would not have posted that....

Ford BUYS the 7.3L PSD (and 6.0L and 6.4L) from International, the contract between Ford and International says Ford CAN'T use the engines they purchase in the bigger trucks because International does not want their engines in competotor's MD trucks! Ford WANTS those engines in the MD lin-up, but they can't have them.

You do realize, well I guess you don't, that the T444E (7.3L PSD) is the most common of all engines in the School Bus and wrecker Medium Duty market right? I guess by definition, that makes that engine a MD product.

The Powerstroke is NOT a medium duty engine, and does NOT like much more then about 50% more HP at most. I've seen plenty of failures.

I've been working on and owning the T444E/7.3L PSDs since 1994 when they were first offered in Ford pickups and International MD Trucks. There goes your assumption that it's not a MD engine again btw. I have not yet pulled a stock engine because of any "failure" of the engine. I have been responsible for maintenance on fleets running HUNDREDS of these engines and outside of a couple exploded from Ether use, never have seen a major engine failure. Does that mean they never fail, no way, but it does take a lot and there is no weakness in them like the KDP. They also DO wear out, like any engine. The better you treat them, the longer they last.

The T444E/7.3L PSD makes 230 HP and 620 lb-ft of Tq in Medium Duty Truck and Bus applications. That is DOUBLE the HP and Tq of the standard "MD" engines of 20 -30 years ago. HP is not an indicator of LD/MD/HD, GVW of the vehciles they are used in is however. In these applications, the engine can be expected to last 200k -300k miles w/o a major component failure. Your BBC and BBF can't do that. No one is arguing that the hop-up potential of the B5.9L isn't better, in fact I stated it WAS better and a lot less expensive. That really has nothing at all to do with the OP's question or wether the engine is "MD" or not.

On the flip side, and it's a good product, I have replaced 5 B5.9L blocks. Two from the KDP, two from cracks between the core plugs on the RH side and one Cummins wouldn't repair under warranty when it smoked #1 cylinder at 23,000 miles and tore up the block.

I have replaced a number of B5.9L engines, mostly I think, from poor maintenance and not an engine issue. The HGs on the other hand, that's an engineering mistake, and I have done dozens of HGs on them, mostly in "MD" trucks.

So, if failing HGs means an engine qualifies as "MD", then the B5.9L is the only one of the two that would qualify. If, OTOH, being good for 200,000 - 300,000 miles in a MD truck w/o any fear of a catastrophic failure (like the KDP) qualifies an engine as "MD", then only the T444E/7.3L PSD qualifies.

Don't get me wrong, BOTH are good products and have their distinctive "nich" market, but it's just plain wrong to say the 7.3L isn't a "MD" engine. It's got more displacement and has sold more units in MD trucks than the B5.9L.

 

[WH401]

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 ?

Stock filtration is more than adequate on both trucks. Free'er flowing intakes tend to give less filtration, unless you use ones that come with a layer of oil in them. The problem with the oil layered filters is you have to get just the right amount of oil on the filter after you clean them or they either won't filter well enough or the excess oil will get sucked into the intake tube and foul up sensors.

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 ?).

Exactly. While the 7.3 is the best diesel engine Ford ever put in their trucks, the injection system is overly complicated and can be a PITA when it doesn't work properly.

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 ?

Running an additive in any engine that was built to run on pre-ULSD fuel is a very important practice. The problem with ULSD is that they took all the sulfur out of it, (went from 500 ppm in the old fuel to 15ppm in the new fuel). The problems that are encountered because of this are the lack of fuel system lubrication from ULSD (in any brand of diesel engine), a higher clouding point (meaning that now it doesn't have to get very far below freezing before the fuel starts solidifying), the fuel is prone to growing algae if sat you long periods, and it produces lower fuel mileage numbers in on road vehicles.

To answer your question, no, the Cummins fuel system isn't more sensitive to ULSD, they're all more sensitive to ULSD.

 

[mlauk]

Ford BUYS the 7.3L PSD (and 6.0L and 6.4L) from International, the contract between Ford and International says Ford CAN'T use the engines they purchase in the bigger trucks because International does not want their engines in competotor's MD trucks! Ford WANTS those engines in the MD lin-up, but they can't have them.

This is why the engine is rated as light duty versus medium duty.

The Cummins Turbo Diesel engine is renowned for its durability, being used in commercial medium-duty and heavy-duty applications worldwide. The simple inline-six cylinder design has up to 40 percent fewer parts than competitive V-8 diesel engines. And the Cummins engine has an average life to overhaul of 350,000 miles, compared to 250,000 for competitive engines. Because of its longevity, the Cummins engine is rated as a "medium-heavy duty" engine, compared to the "light-heavy duty" designation for GM Duramax and Ford Power Stroke diesels.

 

[RobertN]

In the bigger cousins to the two motors mentioned, are any of the manufacturers using "V" configuration motors in big rigs, large trucks ect?

The older engines at our fire station have Cat 3208's(an '86 Ford F8000 buildup), and a Detroit(late 80's GMC Topkick watertender with a 92 series Detroit).

All our newer stuff has in-line motors(mostly 8.9l Cummins).

Is there an advantage to a "V" motor in a light pickup? Would guess a "V" is shorter in length.

 

[3930dave]

Good discussion guys, thnx !

Lost the Ram, it sold yesterday. I stumbled across it last week, not really
knowing what I was looking at. I was trying to verify the tow rating with Chrysler, but couldn't hold the cell call on my way cross country on Friday (it's too old for the Canuck dealers to pull up specs electronically). Some guy bought it yesterday.

This is why I don't buy lottery tickets... it had been listed with the dealer since Dec.!

Snooze/Lose.... it happens......

Not that I ever expect to see that combo again, but did finally confirm the tow rating today with Chrysler Canada - they tell you to use a 5th wheel above 10k#, up to 12,300# for fifth wheel. Would have done the trick for me.

I started using the Stanadyne P.Formula when I got my 3930 (used), firstly to help (long term) with the lubrication issues. It may do other things to the fuel properties well, but the next thing that caught my attention was that it demulsifies (I tend to relate to the term "coagulates" better, but realize that may be a less correct description) very tiny droplets of water into larger ones, so the filter can do a better job.

I get the impression that newer generation diesels/injectors may be more sensitive to this water issue (or maybe more so to the alternative approaches to mitigation ?, ie. alcohol), but figured anything that extracts (w/o any other side effects) more water BEFORE hitting the active fuel components, should help any era of diesel.

At least, where I live - Canada.

Debating checking out this recommended 7.3L.... I would be using it for runs 5+ hours from home, so I'm thinking I'd have to at least carry a spare HPOP and IPR with me. (That comment is me just thinking out loud, not a slag against this 7.3. Corollary to Murphy's law is that with me carrying the spares, I'll never need them.... but that is the way it goes. The other
factor.... parts here in Canuck land are 2x+$ south of the 49'th, so this would be my other main reason for have these critical parts on hand......).

I've also learned to ask the present owner to contact the manufacturer for the Build List, as I'm now hearing some song/dance here in Ontario that dealers can't give out vehicle info based on a VIN, due to new Privacy Laws. I value personal privacy myself, but I'd say they just have badly set up IT systems (Vehicle data is locked to the personal data at a guess).

Been learning lots, thnx again all. D.

 

[ModMech]

This is why the engine is rated as light duty versus medium duty.

How's that??????

International sold hundreds of thousands of T444E (7.3L PSDs) in MD trucks and would not sell then to Ford for use in the MD lineup (competition for International in that market). So, if I get your claim, the B5.9L can't be a MD either because you could not get it in a GM MD truck. Ok, if that's your logic....

The Cummins Turbo Diesel engine is renowned for its durability, being used in commercial medium-duty and heavy-duty applications worldwide.

Sorry, 100% false, the B5.9L is NOT sold in any HD truck and they have sold a very limited number in even MD trucks. Most of the "MD" trucks where the B series is offered, the C series is opted for because it IS a true MD engine. But even that isn't available in any HD application.

The simple inline-six cylinder design has up to 40 percent fewer parts than competitive V-8 diesel engines. And the Cummins engine has an average life to overhaul of 350,000 miles, compared to 250,000 for competitive engines. Because of its longevity, the Cummins engine is rated as a "medium-heavy duty" engine, compared to the "light-heavy duty" designation for GM Duramax and Ford Power Stroke diesels.

Sounds like marketing material, not born out by facts gathered in the field.

 

[R_Walter]

The KDP fix in the older Dodges is a $55 kit plus about two hours of your time. It's pretty simple.

 

[Dmace]

International sold hundreds of thousands of T444E (7.3L PSDs) in MD trucks

Which MD trucks had the T444E? Besides School buses...?

The majority of International Medium Duty trucks that I've seen have the DT466, not the T444E.