1952 B3b with Cummins 4bt

[Dave72dt]

I know________? , I keep______________?  I don't text, A little lost on the acronym.

[ggdad1951]

Comedian, not text...basically " I kid, I kid", but with an accent

Edited December 3, 2013 by ggdad1951

[1952B3b23]

I've been trying to get at least a couple hours in each night after work to do stuff on the truck. I was able to get the drivers side shackle frame mount mounted in the frame so now both sides are done. I also filled a few holes on the side of the frame rail to give it a cleaner look. There's still more to fill in but these three came out pretty well. I'm going to leave a few holes in the bottom flange of the frame rail so that after boxing plates are added if any water gets in there it'll be able to drain back out. Feels good to be making bits of progress on this, gives me more motivation to keep on truckin'. Next step is to box the frame rails in the engine/tranny area. Going to need to get more argon/CO2 mix for the MIG before that can happen. Stay tuned!

-Chris

[1952B3b23]

So I got some work done on the truck this weekend. I mounted the front leaf springs and axle just to see how things are fitting and it went together nicely. I also worked on filling extra holes in the frame that won't be needed anymore.

I also realized that I'm going to have to remove the cross member seen in the pic below. The new tranny cross member is going to have to go there. So I'll remove the old one and then start boxing the rails. Stay tuned for more updates.

-Chris

[1952B3b23]

Did some more welding and grinding on the frame today. Almost done filling and smoothing out all the unnecessary holes. I also removed the unneeded crossmember. But before I did that I welded in two cross bars to hold the frame to make sure it didn't move when the cross member was removed.

I made a sketch of the frame stands that I use to easily rotate the frame. My computer is dead so I can't scan it and post it up that way so I took a picture with my iPhone and I'll post up that for now. Hopefully the pic will be clear enough so you guys can see the sketch. As a side note the schedule 40 black steel pipe in the drawing was bought from Home Depot as were the casters. The metal tubing was stuff I had laying around the garage. Hope this helps someone out if they're interested in building a set for there truck.

-Chris

[Jeff Balazs]

Hi Chris;

Will you be able to replace this cross member with something that has a similar C section shape? I believe that one of the main purposes of this member is to limit..... but at the same time allow a bit of frame flex to occur at this spot. The shape and construction of this member seems to be well suited for this purpose.

 

As you may remember I had to go through an extended exercise to straighten the frame of my truck. During this period I had several fabricator friends of mine involved and our conclusion was that these frames were designed to have a certain amount of flex in them. It seemed to us that most of this flexing occurs within a foot or so either side of where this cross member is placed.

You can in fact see how this cross member works by introducing some twist into the frame by placing the front and rear axles on opposing planes. The member itself will start to twist a little bit in one direction or the other depending on the forces applied. It is actually pretty well engineered to allow for this movement and to limit it at the same time....almost like a perfectly sized torsion spring.

 

Jeff

Edited December 15, 2013 by Jeff Balazs

[1952B3b23]

Hi Jeff,

Thanks for the reply. I didn't know that the cross member functioned in the manner that you described, very interesting. I haven't given much thought to the type of cross member that I was going to replace it with. I was more focused on removing the old one because it was going to be in my way. I could use a piece of channel iron, kind of like what the frame is made out of except thicker gauge as the new cross member. I would have the wide flat portion of the channel facing up so that I can mount the tail of the tranny to it.

As you may know I plan on boxing in the frame rails to add strength. which will also decrease the amount that the frame flexes. I've had several discussions with folks on another forum and they don't think boxing is a good idea because it takes away this flex. I disagree because the frame is still going to flex, maybe not as much but it still will. The boxing will greatly reduce the amount that each frame rail will twist under load but I think the entire frame as a whole will still be able to move. Another driving force for boxing is that this frame is over 60 years old and I'm adding a motor and tranny that are significantly heavier than the stock set up. To add to that it's a diesel so it will produce a good amount of torque. I don't plan on turning this into a pulling truck but I'd like to be as cautious as I can. I'd rather beef it up to much than not enough and have my frame start to develop cracks from the added vibration/ flex and torque. Thanks again for your input, I really appreciate it.

-Chris

[Jeff Balazs]

Chris;

Let me just say that I am basing what I said primarily on observations I made while working on my own frame. That with a bit of wisdom from guy's who do nothing but modify vehicles all day and some supposition on my part regarding the dynamics of the frame design. I have no hard facts or much in the way of documentation to back me up on any of this. My initial knee jerk reaction was that it all seemed really weak. It took a lot of discussion with my fabricator buddies to get over this assessment. Now that I have had some time to re-evaluate it and actually drive it I have to say it all works very well together.

 

The single most significant thing in the observations and alignment measurement I made was just just how much flex and what I will call controlled twist is present in the original frame design. I believe that these features were actually built into this frame design. And that they help preserve the integrity of the various suspension and steering components by allowing and controlling the amount of flex and twist. I guess if I had to put my gut feel about this into one statement it would be to be very cautious about how and where you beef the frame up as it could have detrimental effects on how the truck handles and how the frame itself holds up to the mods. In other words will a frame mod like boxing that eliminates twist in one section actually amplify other conditions to produce a problem in another area? .... like a suspension mount? Or create a dangerous steering condition like over steer under certain conditions?

 

I know you are going to be very cautious in all that you do......I am just bringing this up because it is something to consider as you go through all the steps to build this truck. As I understand your project you will still be using the basic suspension and steering components of the original design. If that is still the case then some effort to allow for controlled flex and twist should I believe be made in order for it all to work correctly.

 

Jeff

[1952B3b23]

Jeff,

I as well am certainly no expert on this. This is the first swap that I have done and it's been quite the learning experience. With that said I am basing my decisions on things that I learn from people who have done this type of stuff before. also by trying to educate myself and making the best guesses on what will hopefully work.

I believe you are correct that the original frame design was made so that it would have the controlled flex and twist. This design was made to handle the power trains of the day. I believe that these flat heads made about 90hp and 175 ft-lbs, that's off the top of my head estimate. I'm sure some of the larger motors made a bit more power. I'm thinking that even by boxing the frame rails. the addition of the new power train and considerable amount of torque will still cause the frame to flex and twist. I'm afraid that without any additional reinforcement this will be far to much and start to cause damage.

I can see that how in your truck it handles relatively well and you see no issues with it. With a stock power train I would not even think of boxing the frame as it very well could adversely impact handling. When I first bought my truck and test drove it I was so surprised at how well it handled for being 60 years old. It was a bouncy ride as expected but other than that I was impressed.

Like I said before I'm no expert custom car builder just a mechanically inclined guy who isn't afraid to tackle a big project. I don't expect the truck to come out perfectly the first time around. If I need to do some further modifications after it's " done " then I will. They will make for good winter projects when I'm not driving it. I guess the proof will be in the pudding as they say. My gut feeling tells me it will turn out decent.

-Chris

[48Dodger]

Flex was built into the frame design to deal with the crappy roads trucks were used for. Think of a truck as a tractor, wagon, and ox....all in one. Gotta keep your feet on the ground to get the work done. Ridgid frames that most hot rodders build today are for the modern roads and offer better response at higher speeds...BUT...if you're gonna mix and match old and modern suspensions...I'd leave some flex.

 

48D

Edited December 17, 2013 by 48dodger

[1952B3b23]

Flex was built into the frame design to deal with the crappy roads trucks were used for. Think of a truck as a tractor, wagon, and ox....all in one. Gotta keep your feet on the ground to get the work down. Ridgid frames that most hot rodders build today are for the modern roads and offer better response at higher speeds...BUT...if you're gonna mix and match old and modern suspensions...I'd leave some flex.

 

48D

 

Thanks for the response Tim. I am going to keep the stock suspension and steering just rebuild it all with fresh components. The more i think of it i'm starting to sway my opinion to the point that a full boxing of the frame may indeed be overkill and actually hurt me instead of help, since i am going to run the stock suspension and steering. I am now leaning more to boxing a smaller portion only where i plan to have the motor mounts and then again a small portion where the transmission cross member will go. This will give the frame more rigidity in those higher stress areas but the rest of the frame will still be open so that it can undergo its "controlled twist/ flex."

 

What do you guys think?

 

Since i was planning on boxing the entire rails i went ahead and welded small patch pieces of steel over unnecessary holes in the frame and filled them in and ground smooth to give a better look. Now that the entire rails will not be enclosed i may need to weld some "cover" plates to the inside of the rails to hide all of these ugly little patches. This will still leave most of the C-channel open, just act as a covering to hide the ugly little filler pieces. It will also give me a good place to attach brake and fuel lines to when the time comes.

 

Thanks to Tim and Jeff for giving me advice on this. Its one of those things that can really make or break the way the truck handles.

 

-Chris  

[Jeff Balazs]

Hey Chris;

I hope you didn't mind me butting in. When I was looking at beefing my frame up some similar considerations were pointed out to me. What kept coming up was how we were going to have to compensate if we stiffened it up too much. This prospect seemed like I might end up chasing endless problems that did not exist within the original design.

Certainly what you are doing will require specific mods and reinforcement. And I don't know if the extra power will make as much difference as the added weight and vibration? My guess is that the frame will handle the extra power just fine. You don't seem like someone who has a tendency to get too crazy. Of course I suppose there is always the temptation to stick your foot into it?

 

Jeff

[1952B3b23]

Hey Chris;

I hope you didn't mind me butting in. When I was looking at beefing my frame up some similar considerations were pointed out to me. What kept coming up was how we were going to have to compensate if we stiffened it up too much. This prospect seemed like I might end up chasing endless problems that did not exist within the original design.

Certainly what you are doing will require specific mods and reinforcement. And I don't know if the extra power will make as much difference as the added weight and vibration? My guess is that the frame will handle the extra power just fine. You don't seem like someone who has a tendency to get too crazy. Of course I suppose there is always the temptation to stick your foot into it?

 

Jeff

 

Hey Jeff,

 

Not at all, i appreciate the comments and all the thought and input you are putting into this to help me out . I think with boxing the rails only where the motor mounts will go and tranny cross member this will be adequate to handle the load and vibration of the motor. That'll give me a good balance between added support and allowing the frame to flex as it was designed to do. Theres a guy over on the 4bt Swaps forum that put a 4bt into a 60's Dodge town wagon and didnt box the frame in at all and has been driving it for years now without any problems (according to him). I am going to use hydraulic fluid filled motor mounts that i have heard cut down on the vibration of these 4bt's a great deal. The step van that my Cummins motor is out of came with these installed so i figured it'd be a good idea to use them. If i still think that the vibration is a lot i can put a harmonic balancer on there thats made by Fluidampr which i have also heard works well, they are just pretty darn expensive. Im certainly not going to get to crazy with this thing but im sure ill have my foot to the floor at times... maybe more than i should haha. Im not building the truck to be a racer just a fun ride that will hopefully get decent MPGs too. 

 

Thanks Again,

 

-Chris

Edited December 16, 2013 by 1952B3b23

[1952B3b23]

Well guys here i sit on my lunch break at work on this snowy New England day... ive decided how i am going to proceed with the frame boxing, im not going to do it yet. I will get the front suspension re-assembled, install "Old Daddys" disc brake conversion kit and put the front end on the ground. Then i'll set up the rear axle to go in, weld up the spring perches/ set the pinion angle. I want to run the pinion angle at 5 degrees up so that i can run the motor at 5 degrees down and give myself more clearance between the transmission hump and the bottom of the cab. I wanna minimize how much i need to cut out of the floor of the cab to save myself some work and keep the cab inside looking clean. Then i'll put the cab back on the frame and start mocking up how the motor and tranny will fit between the rails, make motor mounts, tranny mount, etc. This will give me more time to consider the boxing and allow me to see how all the different components are working together. 

 

What'd you guys think?

 

Thanks,

 

-Chris

[Dave72dt]

Pinion angle needs to be set with the vehicle at ride height.  That means you'll have to load the front and rear suspension with the weight it would normally have on it. Where will the suspension be  with the full drivetrain, sheetmetal and box on it.  If you can clear at 3 degrees instead of 5, your driveshaft and joints will be happier or you may want to consider a CV joint on one end.

 

Mounting the engine to the frame rails will require boxing.  Because of the flex in the rails,  the weight will twist them without the boxing.   Mounting it from a crossmember does not.

[Don Coatney]

This might or might not help

 

 

 

 

[1952B3b23]

Pinion angle needs to be set with the vehicle at ride height.  That means you'll have to load the front and rear suspension with the weight it would normally have on it. Where will the suspension be  with the full drivetrain, sheetmetal and box on it.  If you can clear at 3 degrees instead of 5, your driveshaft and joints will be happier or you may want to consider a CV joint on one end.

 

Mounting the engine to the frame rails will require boxing.  Because of the flex in the rails,  the weight will twist them without the boxing.   Mounting it from a crossmember does not.

 

Duh, i dont know what i was thinking but i definitely missed that crucial step in my original post, thanks for pointing that out Dave. I can live with 3 degrees if it doesn't clear that's OK I'll just modify the floor of the cab to make it work. 

 

Im running a front sump oil pan and the motor mount attachment points are right at the front of the engine. The front sump oil pan does not allow for a cross member in order to mount the engine to. It sounds like i should continue with the boxing of the rails where the motor and tranny will go so that the additional weight will be figured in when i go to set the pinion angle after. I basically know where the motor is going to mount and the tranny cross member will be so knowing where to box in those areas isnt hard.

 

Thanks again,

 

-Chris

[1952B3b23]

Thanks Don, i've actually seen that before and found it to be helpful.

 

-Chris

[1952B3b23]

I decide to go ahead and box the frame like i originally planned. I talked with a bunch of people who build hot rods for fun or do it for a living and have been doing it for a long time and their opinions where all in favor of boxing. Its a tried and true method of strengthening a frame to allow for the use of a power plant that produces much more power than it was originally designed for. This makes me feel much better about the build as its something that i had a strong gut feeling that needed to be done. I know questions had arose about what kind of effects will it have on handling. The short answer is that im not building a race car here its still a truck with leaf spring suspension and straight axles, its never going to handle that great.  I'm totally fine with this thing handling like a truck, that's exactly the way i want it. 

 

The frame boxing on the passenger side is done. I made a cutout in the plate so the spring shackle can easily be removed. I also welded a piece of angle iron over the hole in the top flange of the frame rail that the bed cross member bolts to. That way when i go to bolt the bed down i'll be able to get the nut on. This also has a benefit over just leaving an opening because it will keep me from dropping the nut down into the frame rail. The inside of the frame rail was primed and painted before boxing. I also primed and painted the inner surface of the boxing plate. The edges where welding would take place were sprayed with weld thru primer on both the plate and rail. I used "Dynaflux AL-OXIDE" that i got at a local welding shop and it seemed to work well. I've attached pictures for your viewing pleasure. 

 

-Chris 

[48Dodger]

If you decide to "heat it up" later on....you're ready to go!

 

48D

[1952B3b23]

Thanks Tim! Yea she should definitely be able to take some "heating up" now. Next is to box in the drivers side rail. Stay tuned for that.

-Chris

[Dave72dt]

Give that angle iron a test run with a bolt and nut to be sure you have room to swing the wrench and tighten it.  That bolt is supposed to be a carriage bolt and you can't tighten them from the top.

[1952B3b23]

Thanks for the heads up Dave. I didn't know it's a carriage bolt, my truck didn't have a bed on it when I bought it. Hopefully a gear wrench will do the trick if it's tight.

-Chris

[Dave72dt]

That's why you should try it now, before you repeat it on the other side. Depending on how many threads will stick out the bottom of the nut, you may or may not be able to get the wrench off later.

Test it with an open end or regular box end and a common hex bolt. Gear wrenches don't normally reverse without flipping them over and if you can't get the wrench off.....

[Young Ed]

That's why you should try it now, before you repeat it on the other side. Depending on how many threads will stick out the bottom of the nut, you may or may not be able to get the wrench off later.

Test it with an open end or regular box end and a common hex bolt. Gear wrenches don't normally reverse without flipping them over and if you can't get the wrench off.....

 

Depends on which type you have. All of mine have a little lever to reverse them.