Frame Swap - And off on a tangent...

[scottystills]

Well looking at some frame strengthening options. Tis the season for contemplating winter projects...

We're all aware how much these frame tend to flex, and I'd like to minimize it as much as possible. Starting to think my winter project might include a power plant upgrade so would likely be a necessity to make sure the frame will handle it. Alternatively would moving to a link/coil front susp take some of the stress off the frame that the leaf springs seem to cause?

The way I see it I have 3 options:

1. Plate/box the existing frame. Pros: easier to source, probably cheaper in the long run. Cons: Seems like a lot of work to work around the existing frame attachments, not sure how much strength it will net compared to other options. Difficulty 2/5

2. Source and modify K30 boxed frame. Pros: Easy to source, fully boxed frame, should be straightforward to move existing suspension from one to the other. Cons: Frame needs to be shortened but I luckily have a buddy who is a welder/fabricator who should be able to manage the job very well. Body mounts need to be moved I'm sure but should be easy enough. Difficulty 3.5/5

3. Build new frame. I blame some of our members for putting this idea in my head as I follow their frame build threads. Pros: All new material, easy to customize during build. Cons: Time consuming and difficult to do properly, very likely the most expensive option. Difficulty 5.5

Tossed up, but probably the first step of the next iteration of my truck. Definitely don't want to go way down powerplant and suspension upgrades just to find the frame isn't up to the job.

Thoughts?

 

[Hogback Fabrication]

The way I see it I have 3 options:

1. Plate/box the existing frame. Pros: easier to source, probably cheaper in the long run. Cons: Seems like a lot of work to work around the existing frame attachments, not sure how much strength it will net compared to other options. Difficulty 2/5

2. Source and modify K30 boxed frame. Pros: Easy to source, fully boxed frame, should be straightforward to move existing suspension from one to the other. Cons: Frame needs to be shortened but I luckily have a buddy who is a welder/fabricator who should be able to manage the job very well. Body mounts need to be moved I'm sure but should be easy enough. Difficulty 3.5/5

The way I read that, you make it sound like 76-91 K30 frames are boxed. They aren't. They are thicker than the rest of the truck line, but otherwise the same deal as the rest.

IMO, crossmembers are way more important than boxing. Via a cage, crossmembers, etc.

 

[scottystills]

The way I read that, you make it sound like 76-91 K30 frames are boxed. They aren't. They are thicker than the rest of the truck line, but otherwise the same deal as the rest.

IMO, crossmembers are way more important than boxing. Via a cage, crossmembers, etc.

Ha! You're right I was thinking one step ahead of myself... Thicker and would plan to box it before swapping in. IIRC the K5 frame is something like .16x" vs the K30 is .26x". Finish the boxing with .25" before transferring everything.

 

[rampage]

IIRC the K5 frame is something like .16x" vs the K30 is .26x". Finish the boxing with .25" before transferring everything.

http://coloradok5.com/forums/showthread.php?t=235499




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[scottystills]

Read that one a couple weeks ago. Got the K5 number right, little off on the K30...

The heart of the question is though, how much is necessary and how much is overkill? Does boxing the existing frame give me the strength I'm looking for or is it more beneficial to put in something stronger while the body's off anyway?

 

[LaRue91]

I bought a diy4x box kit for mine. Will be adding crossmembers and sliders too, should help with my flex issues / cracking in frame

 

[Stomis]

Weld your crossmembers to the frame and then box it IMO.

 

[scottystills]

True enough. Well I'll start putting my parts list together and should I come across a readily available CCK30 I'll think about it, otherwise boxing it is.

The plan is for a mildly built 12v, really don't want the already flexy frame to start twisting up..

 

[Hogback Fabrication]

The plan is for a mildly built 12v, really don't want the already flexy frame to start twisting up..

Not that I think reinforcing the frame is a bad idea, but my K30 supposedly has about 180K on it since it's 12V swap (only about 35K by me) and it's still 100%, totally stock frame.

 

[scottystills]

Not that I think reinforcing the frame is a bad idea, but my K30 supposedly has about 180K on it since it's 12V swap (only about 35K by me) and it's still 100%, totally stock frame.

Ya this is kind of what has me thinking of an upgrade. The front of the frame is already getting beat up enough twisted by leaf springs, steering box, etc. Not sure it's going to love at 12v torquing on it all the time also...

Well hopefully I find the perfect CC K30 to steal a frame from about the same time as I find the perfect W250/350 with a 12V/NV4500.

 

[dyeager535]

The heart of the question is though, how much is necessary and how much is overkill?

I think that is a pretty arbitrary question/answer. Some of the rigs may have worse flex than others due to the wheelbase, how the body is tied into the structure, etc.

Realistically a proper cage is the best answer, but boxing will help. The answer of "how much" is nearly impossible to quantify. I agree with welding in the crossmembers (and IMO everything riveted to the frame that doesn't need to be easily removed, like spring hangers, etc. as you are going to increase the work the suspension must do, loading the mounts more) and where you can fit it, additional tubing that traingulates as much as possible. Unfortunately on the K5, space is limited, the only spot easily braced up is behind the t-case/in front of the tank. Might be able to add some tube (such as extreme front and rear of frame) and the front crossmember (where combination valve is located) can be boxed as well.

I grabbed some spare frames to source the "plating" from, but that DIY4X kit, if pretty close for the later K5s, would save a lot of cutting and grindng over doing it yourself. I don't see paying for a spare frame, or sheet of steel, then spending the time/money to cut and fit it, as being cost/time effective vs. the $210-240 they want for their kit, IF the kit is real close.

 

[scottystills]

So all this being said, while I've got your attention how about I ask about engine/trans/tcase options?

Assume the frame is all done; I'm shopping for a donor truck atm. Liking a 96 W250 or W350 w/ the higher output 12v, NV4500, and NP241DLD/DHD. IIRC though Dodge switched to a driver drop in 94(?).

I'd only take the W350 if I were going to scrap the TC altogether...

Don't want the DHD; no SYE. But I would like the DDX code 4500. Is the 241DLD worth swapping the input onto a Chev version for pass drop, or is there another option to put behind the 23/29 spline 4500 output? The GM 4500s are all 32 spline I believe, so thinking I could use the input from a Dodge 241 on a Chev 241?