Towing with a Powerstroke 7.3L (expectation/realistic)

BigToe wrote:

shartflhs wrote:
Unsubscribing from this topic. It is so far off the original topic and not of interest. People need to learn7-to open new one. Thanks for wasting my time.

You are most welcome. Come back anytime, and we will be quite happy to waste some more. We'll always be here for ya!

BTW, speaking of time, when I compare your 11 total posts, which incudes your complaint above, to Glen's 21,078 posts that he has contributed to the RV.net community over his 13 years of membership, where he has added content that is not only of value to RV'rs around the world, but that is also of value to RV.net in the form of attracting reads and hit counts that generate ad revenue which sustains the kind of member participation that maintains the business case for this forum, where Glen has taken a lot of TIME out of his life to answer questions that folks have had, as well as share his own experiences (including his evolution away from the 7.3L), all of which creates continuing conversation that remains of interest long after the OP has abandoned the thread... then maybe you are the one who should "learn how to open up a new thread" on whatever specific topic interests you.

Perhaps if you spent more time contributing to the forum, rather than just complaining about the forum (at least 10% of your posts are a complaint, a mathematical fact determined without having read any of your other posts), then perhaps you'd feel less like your time was wasted.

Glen... thank you for the thorough evaluation of the reasons you estimate you find the rear deflection in your 4x4 International. Your specific observations regarding spring hanger placement, rear blocks, and front drive axle to oil pan clearance are very relevant to towing with the Powerstroke 7.3L, because the Ford Super Duty trucks that the 7.3L is fitted in have the exact same issues.

Obviously, an engine cannot tow a trailer by itself, not even the vaunted 7.3L. Even the most revered Powerstroke of all time can't pull a trailer from an engine stand. Towing still requires a truck to accompany that engine to get the work done.

The Ford Super Duties of the 99 up era are notorious for excessive rear suspension deflection relative to the overall level trim height of the vehicle. There was even a Ford TSB issued in 1999 that provided a factory approved means of changing the rear blocks from 2" to 4", and vise versa, due to the noticeable rear deflection under load.

The chassis cab F-450/550 trucks had a factory "low deflection" package, where different blocks and U bolts, and in some wheelbase configurations, driveline cardan joints are used, all to address the issue of the rear suspension deflecting to where the truck appears overloaded with the headlights pointing toward the sky, even while the load that causes the deflection is well under the capacity of both the axles and the springs suspending the axle.

So if choosing to tow with a 7.3L equipped Super Duty, one "realistic expectation" to keep in mind is that the rear suspension may deflect more than visually pleasing, even when the loads are well within the rear GAWR. For those unfamiliar with Fords, it may help you to know that there are some Ford approved parts that mitigate this deflection.

And for those why such parts may help or are even necessary, Glen's excellent post regarding his International truck offers an illustrative template toward understanding some of the issues involved.

Big Toe ,how many give a **** about these 14-18 year old antiques . The OP just wanted some real world towing with a 7.3 Superduty . He's overloaded with the weight he wants to tow, he didn't need any info about welding trucks or whatever you guys wandered off to.

I love some of you guys, and your good old boy club ,talking about these vintage relics. I got a clue for you this is 2016. We got out of the 80's ,and 90's long ago.

shartflhs wrote:
Unsubscribing from this topic. It is so far off the original topic and not of interest. People need to learn7-to open new one. Thanks for wasting my time.

You are most welcome. Come back anytime, and we will be quite happy to waste some more. We'll always be here for ya!

BTW, speaking of time, when I compare your 11 total posts, which incudes your complaint above, to Glen's 21,078 posts that he has contributed to the RV.net community over his 13 years of membership, where he has added content that is not only of value to RV'rs around the world, but that is also of value to RV.net in the form of attracting reads and hit counts that generate ad revenue which sustains the kind of member participation that maintains the business case for this forum, where Glen has taken a lot of TIME out of his life to answer questions that folks have had, as well as share his own experiences (including his evolution away from the 7.3L), all of which creates continuing conversation that remains of interest long after the OP has abandoned the thread... then maybe you are the one who should "learn how to open up a new thread" on whatever specific topic interests you.

Perhaps if you spent more time contributing to the forum, rather than just complaining about the forum (at least 10% of your posts are a complaint, a mathematical fact determined without having read any of your other posts), then perhaps you'd feel less like your time was wasted.

Glen... thank you for the thorough evaluation of the reasons you estimate you find the rear deflection in your 4x4 International. Your specific observations regarding spring hanger placement, rear blocks, and front drive axle to oil pan clearance are very relevant to towing with the Powerstroke 7.3L, because the Ford Super Duty trucks that the 7.3L is fitted in have the exact same issues.

Obviously, an engine cannot tow a trailer by itself, not even the vaunted 7.3L. Even the most revered Powerstroke of all time can't pull a trailer from an engine stand. Towing still requires a truck to accompany that engine to get the work done.

The Ford Super Duties of the 99 up era are notorious for excessive rear suspension deflection relative to the overall level trim height of the vehicle. There was even a Ford TSB issued in 1999 that provided a factory approved means of changing the rear blocks from 2" to 4", and vise versa, due to the noticeable rear deflection under load.

The chassis cab F-450/550 trucks had a factory "low deflection" package, where different blocks and U bolts, and in some wheelbase configurations, driveline cardan joints are used, all to address the issue of the rear suspension deflecting to where the truck appears overloaded with the headlights pointing toward the sky, even while the load that causes the deflection is well under the capacity of both the axles and the springs suspending the axle.

So if choosing to tow with a 7.3L equipped Super Duty, one "realistic expectation" to keep in mind is that the rear suspension may deflect more than visually pleasing, even when the loads are well within the rear GAWR. For those unfamiliar with Fords, it may help you to know that there are some Ford approved parts that mitigate this deflection.

And for those why such parts may help or are even necessary, Glen's excellent post regarding his International truck offers an illustrative template toward understanding some of the issues involved.

Unsubscribing from this topic. It is so far off the original topic and not of interest. People need to learn7-to open new one. Thanks for wasting my time.

Bedlam wrote:
The other steps I have seen take a cutout from the deck and a stair well is welded in place that does not extend sideways beyond the deck rub rail. You see these more on bucket trucks.

Yes, I've seen those too.

Because I'm limited on the max length of the truck, so I can fit it into my shop at night, I couldn't build a low deck extension platform and steps on the back of the flatbed, like the bucket trucks have. It would be nice though.

One idea I have is to build a bi-fold, fold-down stairway, that can also act as a tailgate when up, to keep stuff from falling out the back of the truck. It will make it more difficult to haul over-length items in the bed though, unless I can swing the whole stair sideways out of the way. I have to do more thinking on the design.

Another idea is to get one of those rental box truck loading ramps and mount it under the bed, where that storage box is seen in the pic above. There are benefits and drawbacks to a ramp, which I need to do more thinking on.

I looked at the Glow Steps. They appear very similar to the aluminum folding accordian steps I already have. I think I'll pass on those, for this application.

The other steps I have seen take a cutout from the deck and a stair well is welded in place that does not extend sideways beyond the deck rub rail. You see these more on bucket trucks.

I'll have to look at the Glow Steps.

I do have a set of the aluminum accordian steps for my camper, on the other truck. I don't like them as much as another set of steps I have.

These plug into a receiver tube I welded to the rear bumper. They stay on the truck all the time. The steps' tube is long and has 2 pin positions, so they slide out about 6 or 8 inches and are easier to use.

Attach a set of Torklift GlowSteps to your truck deck so it is easy walk up and down instead of having to climb. It's not any different than people with rear entry TC's which have tall basements.

Big Toe, Thanks. The lack of intercooler would explain some of the lower rated power output of the van 6.0. Also thanks for explanation of the inter/after cooler issue.

Big Toe, Thanks. I really like the new truck (International).

The International looks overloaded, but it is actually way underloaded. It weighs 13,000 lbs less than it's 33,000 GVWR and is using only about half of it's 21,000 lb rear axle weight rating. The rear springs are rated more than the axle, with 23,500 lb main packs, plus overloads, according to the factory build sheet I got with the truck.

The truck was ordered by the Forest Service with the extra heavy rear springs. I don't know why they didn't order it with the 23,000 lb axle too. The 23K axle was available with an air operated locking differential, which was not available in the 21K axle.

The reason the truck sits low in the rear and high in the front is because of the way International builds their 4x4 trucks. They have to use very tall front springs, for the axle and engine oil pan to clear each other. The 4x4's appear to sit about 8" higher in the front than the 2wd's, from what I can tell by comparing with other 2wd 4000 series trucks I run across.

The truck has spacer blocks under the rear springs to lift it up. The rear spring hangers are also mounted lower on the frame than the 2wd trucks, with drop brackets that allow the lower portion of the spring hangers to bolt on below the bottom of the frame rails.

Despite their efforts to increase the rear suspension height, it is not enough to make up the full height difference in the 4x4 versus 2wd front suspension. Possibly that's as far as they could raise the rear, due to driveline angles, or some other issue... I don't know.

I should have taken very accurate before-build and after-build rear height measurements, to know exactly how much the truck squatted. Unfortunately, I didn't do that. However, from all that I can notice from before and after pics and from working on the truck, climbing up and down it 100's of times, relationship between the overloads and their bump stops, etc, it doesn't appear to me the truck sagged more than inch in the rear from what I loaded on it, if it even sagged that much.

I would prefer if the truck did not sit nose-high. It looks stupid. However, I really don't want the rear to sit any higher than it does, even if it can be lifted. It's difficult enough to climb up and down the rear of the bed as it is. Any higher would just make my job harder.

So far as I can see, there is nothing I can do about lowering the front, without risking the axle hitting the engine. So, it is what it is and I accept it...

For size comparison, here is a pic of the other 4x4 F350 parked next to the new truck (I was using the crane to pick the welder off the F350). The F350 has 33" tires and aftermarket heavy rear springs on it.


The spacer block under the rear springs is visible here, as well as the drop brackets for the spring hangers, underneath the frame rail.


Here are seen the upper 2 bolt locations in the frame above the spring hangers at both ends of springs, where the spring hangers would mount on a 2wd model.

SoCalDesertRider wrote:
I heard the vans have a smaller intercooler than the pickups too? Could barely see anything in front of that van.

Ford vans did not have a factory installed intercooler at all.

Edited to add: Wow, that's a big, bad, green machine you've got there. It almost looks overloaded (judging solely by rear deflection in the photo). I can't imagine all that equipment being handled by an F-350. Clearly, you've brought along a few more toys to work with.

Thanks for posting the pics of your new to you truck. They help in visualizing the size and scale of rig you are now working with.

SoCalDesertRider wrote:
A long time ago, Detroit Diesels had aftercoolers. I know the TA stood for Turbo Aftercooled.

I assume the aftercooler was placed after the turbo on the intake side? It seems intercoolers must have proven to work better than aftercoolers at cooling the intake air going into the engine? Does anyone use aftercoolers anymore?

Glen, I think there is just a semantics issue here. I'm not sure how you are interpreting my previous post, so let me clarify.

The intercooler on the 7.3L is an "inter-mediary" cooler, hence the name "inter-cooler". It installs in-between the turbo and the engine, "inter-connecting" those two air pumps (the compressor, and the engine).

In my earlier post above, I discussed how the intercooler cools the intake air of the engine. And I meant just that. The engine pump. Not the compressor pump.

The compressor pump heats up the ambient air it compresses, significantly. Then this hot, pressurized air enters the intercooler, which cools down the super heated air. This "cooled" air is still hotter than the ambient air that entered into the compressor, but without the intercooler the air would have been 100 degrees hotter, and thus less dense with oxygen molecules per unit volume that is available in the cylinder.

It sounds like the DD style TA "aftercooler" you are looking for is indeed the self same "intercooler" on the 7.3L. There does not appear to be any difference between the two, from your description.

To understand the semantic difference between intercooler and aftercooler, I'd have to use a non engine example, like my two stage Ingersoll Rand Type 30 air compressor. The two cylinders in the air pump each serves as a separate stage. Air enters into the first cylinder, and gets compressed. Then, before this compressed air is routed to the second cylinder to get even more compressed, it is first routed through an intercooler (a roll of finned copper tubing surrounding the flywheel fan).

After being intercooled, the air enters the second cylinder for the secondary stage of compression. Then, this highly compressed, high pressurized air would normally fill the 80 gallon tank, but instead, the final compressed air is routed to an aftercooler (a radiator like core mounted to the belt guard). So, in the case of this two stage air compressor, there is both an intercooler AND an aftercooler, and they are not the same. One cools the compressed air between stages, the other cools the compressed air AFTER all compressing stages are complete.

This is not the case with the turbocharged diesels having just a single turbo. Whether a manufacturer chooses to call it an intercooler or an aftercooler, in the case of cooling the compressed air for the engine's consumption, the terms (or at least your meaning of the terms as expressed above) are interchangeable when it comes to the 7.3L. Most call it an intercooler.