OBS F250 slow adventure build

[amgvr4]

I really appreciate all the complements. The build has turned out pretty much the way I wanted it to. I use the truck to pick up a couch today in Seattle and it worked great. It is a little floaty on the freeway but I think some of that is the 4" of rake that the truck has at the moment. I have done a little looking into sway bars but I will deal with that later. First I want to get the back done and see what difference that makes. Having good shocks on the rear will definitely help. Tomorrow I will figure out what is up with the limit straps as that is the final piece of the puzzle for the front suspension. Once those are on I can really flex it out to see how it does. I took some before pictures flexing on a little dirt hill by my house prior to removing the old axle. When I get a chance I will take some with the new setup to post side by side as a comparison. I did a little test on that hill last night and I can say the preliminary results were amazing compared to the D50. I don't have a front drive shaft in yet so with only 2wd and no rear locker the biggest limitation was the rear traction.

Here are some daylight pictures from today

I need to find some F350 badges now


Since I last filled up with diesel it has come down over $1 per gallon! I'm loving this!

 

[BeenThereDoneThat]

Loved that bumper design...lookin good!

 

[java]

Looks great!

 

[underdrive]

I need to find some F350 badges now

No you don't - need to de-badge it completely and leave people confused Excellent work by the way! And yes sway bars will help a lot at higher speeds, front one will be more noticeable than the rear so go for that first.

 

[amgvr4]

I got a chance to flex the truck out a little. I didn't push it to the limit since I don't have limit straps on yet. Sure beats the 1" of articulation from the d50.

 

[snowaddict91]

Man combined with the frame flex you have some serious articulation now! Lol but seriously, wanna do my truck next?

 

[Seabass]

Just....WOW! Such a great job on that swap.

 

[IdaSHO]

Looks great.

Though Im a bit concerned about that track bar mount to the frame.

OE Superduty rigs with the factory coil sprung front end has a track bar mount that ties into the cross member as well IIRC,

Other than that, looks great. I swapped in a KP D60 under my OBS a few years ago. Just running big block leafs.

By far the best mod Id done to this truck.

 

[underdrive]

Ugh, that poor frame... do you dare open your doors when twisted up like that? For what it's worth, some medium-duty trucks have essentially three cab mounts, the two front ones are in their usual location outboard of the frame rails but the two rear ones are pretty much right next to each other in the middle of the crossmember. Frame twists rather impressively, yet entry/exit of cab is still easy. Something to maybe consider, especially with such a long cab.

 

[amgvr4]

Man combined with the frame flex you have some serious articulation now! Lol but seriously, wanna do my truck next?

Lol! OBS fords wouldn't have any articulation with stock suspension if it wasn't for good old frame flex! I have thought about doing this again for someone else, mostly because it would be so much faster and better a second time around, but also to help fund a plasma table!

Seabass;
Thank you, I am really excited to get the rear done and drive shaft in so I can go wheeling in the mountains. I forgot to take measurements when I took those pictures today, so I went back after work and tried again. At the spot in those pictures I still have 4" of extension on the passenger side and 3" of compression on the drivers side. My bushings are definitely starting to bind at this point, however I was able to skirt the dip in the wall my tire was in and make it up another foot. At that point I still had 3" extension and 2" compression left. If I was to remove the top link on the passenger side I would easily be able to use the full stroke of the shocks and probably make it to the post at the end of the wall. The rear shocks and shackle flip should help as well.

 

[amgvr4]

Ugh, that poor frame... do you dare open your doors when twisted up like that? For what it's worth, some medium-duty trucks have essentially three cab mounts, the two front ones are in their usual location outboard of the frame rails but the two rear ones are pretty much right next to each other in the middle of the crossmember. Frame twists rather impressively, yet entry/exit of cab is still easy. Something to maybe consider, especially with such a long cab.

It always bothered me that domestic manufacturers took so long to switch to fully boxed frames that have some rigidity to them. The only real solution I know of is to plate the inside of the frame and add some more x-braces to help with the terrible torsional stiffness these rigs have. I will go that rout later on when I get more of a chance to pull the bed and do it properly. The doors are actually very easy to open and although not the same as when level, they do not bind hardly at all. I do need new cab mounts, and it would be super easy to add some extras inbetween the factory ones. I had never though of that before, thanks for the suggestion.

 

[underdrive]

It always bothered me that domestic manufacturers took so long to switch to fully boxed frames that have some rigidity to them. The only real solution I know of is to plate the inside of the frame and add some more x-braces to help with the terrible torsional stiffness these rigs have. I will go that rout later on when I get more of a chance to pull the bed and do it properly. The doors are actually very easy to open and although not the same as when level, they do not bind hardly at all. I do need new cab mounts, and it would be super easy to add some extras inbetween the factory ones. I had never though of that before, thanks for the suggestion.

See I actually like the C-channel frames, much easier to route stuff inside them (harnesses, air/fluid lines, etc.), and, what's even more important, super-easy to clean - with boxed frames once the dirt gets inside good luck getting it out, and once said dirt mixes with moisture, or even worse, that liquid devil some states spray on their roads for deicing purposes, it's a recipe for disaster in the long run. Something else to consider is the material used for the frames: C-channel is usually just your regular mild steel you can cut and weld day in and day out, boxed got some after-treatment that makes them funky about additional welding and prone to develop cracks afterwards. I think the advent of boxed frames has more to do with passenger comfort than brute strength, as medium- and heavy-duty trucks have no problems with C-channel frames, and some are even aluminum. Those are designed to twist something fierce though, as a matter of fact most HDTs have the rear suspension set up in such a way that the axle also functions as a swaybar, there is next to no articulation there and instead it's the frame that takes care of that. Hence the odd cab-mount setup on the MDTs with light-duty-sourced cabs, their frames are designed to twist a whole lot more than the pickup trucks so the cab mounts are arranged to accommodate that without causing the cab to rip apart.

So with a twisty C-channel frame I'd not only avoid adding more cab mounts, but, as mentioned, consider rearranging the rear mounts MDT-style. On the other hand, if this were a newer hydro-formed boxed frame, then adding the extra cab mounts may be worth it. There is a build on Pirate where someone is dropping an early-'90s cab on a '06 or '08 frame, maybe worth going through his thread and seeing how the newer Ford frames are set up in comparison to how your cab sits, IIRC he has to move his rear mounts outboard of the frame rails so that may be an easier solution for you instead of adding another pair midpoint under the B-pillars. But again, his is a very torsionally-stiff frame, so he can afford outboarding the mounts, so not something you wanna be considering till your C-channel has been boxed and x-braced and whatever else you have planned for it.

 

[snowaddict91]

Lol! OBS fords wouldn't have any articulation with stock suspension if it wasn't for good old frame flex! I have thought about doing this again for someone else, mostly because it would be so much faster and better a second time around, but also to help fund a plasma table!

.

Yeah in my truck with the worn out stock springs I just watch the frame flex in my mirror when I go over a dip in the road! Would love to put a 60 in the front, maybe someday...just can't justify the $$ when everything works fine.
But once again awesome fab skills on this thing! I still really like your back bumper too.

 

[Seabass]

As far as frame flex..... That's correct, semis and heavy trucks pretty much use c-channel frames. There's nothing wrong with them. Does it look good to see the twist like that? No. But ford knew that it would flex. The rear cab mounts on these crew cabs are pretty close together- in the ball park of two feet (I've never measured them). They are also REALLY soft and flexible. Aftermarket rear cab mounts can be really stiff. I've heard of guys actually taking aftermarkets off and putting factory ones back on. So the frame flex isn't really hurting much. I've drove these trucks for years and have never had any frame related issues from flex. I have had to glue a windshield in a couple of times- and it was due to excessive flexing of my frames: coffee drink. But even that wasn't a big issue. I'm still lovin on the truck. I'll likely just keep rockin the pile of leaf springs- but it's mostly cause I'm to lazy to do something this cool.

 

[amgvr4]

I guess that is the great debate, is there anything detrimental about frame flex or is it part of the engineered function of the frame? If it doesn't cause any real problems then I am fine with it. My full length sliders I want to build will help and once the rear is done it won't put so much of the load on the frame since the suspension will move more freely.

I really need to fix the rubbing on the radius arms. It is limiting my already lack luster turning radius more than I want to put up with. First quick fix will be some .250 slip on wheel spacers and it that isn't enough I will have to notch the arms themselves. I really wish I would have decided to switch to coilovers before welding everything in place. If I would have mounted the main brackets inboard 2" I would have been in the clear. I will also most likely make an add on brace that goes from the frame side track bar mount to the crossmember just for added piece of mind. My limit straps should show up tomorrow. After I get those on I might take off the passenger side top link and let it flex as far as the travel will let it.