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#2449025 - 02/09/18 08:07 AM Re: New Rotisserie and Plymouth frame cut for Dakota sub-frame. [Re: poorboy]
moparx Offline
master

Registered: 09/03/03
Posts: 8278
Loc: north of coder
i don't see why that won't work ray. use grade 8 bolts and steel lock nuts that have the last couple of threads deformed [grade 8 as well] at final assembly. torqued at the proper value for the bolt size, and with as many bolts as you show, the shackles aren't going anywhere. A-bodys had the shackle hangers bolted on from the factory, so if it was good enough then, your solution will be good enough now.
beer

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#2449067 - 02/09/18 10:07 AM Re: New Rotisserie and Plymouth frame cut for Dakota sub-frame. [Re: moparx]
Old Ray Offline
member

Registered: 09/20/16
Posts: 77
Loc: British Columbia, Canada
Thank you Gentlemen, good input. I had to move the spring mount pads on the diff tube so the brackets are off and I will reset the pinion angle (3 deg?) when all done and weld them on. Front spring mounts still need bottom holes drilled in the frame so will look at flipping them as well. I have ordered lowering blocks from eBay, should be here in a week or so. Living in a (beautiful) small town in the hinterlands makes parts sourcing "interesting"!
wrench

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#2449164 - 02/09/18 02:52 PM Re: New Rotisserie and Plymouth frame cut for Dakota sub-frame. [Re: Old Ray]
poorboy Offline
master

Registered: 01/19/03
Posts: 6129
Loc: Freeport IL USA
Set the pinion angle 2-3 degrees down from the angle of the transmission main shaft centerline, with the rear end supporting the weight. If you do it just hanging, the angle will be wrong. I get to buy a set of 6 degree wedge plates to correct my pinion angle because I got in a hurry and didn't have weight on the axle. Yea, it changed that much from just hanging to having the chassis weight on the axle! Gene

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#2450897 - 02/12/18 06:38 PM Re: New Rotisserie and Plymouth frame cut for Dakota sub-frame. [Re: Old Ray]
Old Ray Offline
member

Registered: 09/20/16
Posts: 77
Loc: British Columbia, Canada
I had already decided and built exhaust outlets (kina NASCAR style) in front of the rear wheels, I knew this was going to cause problems and I was right, the frame is in the way and there is no way to work around it, and one of the body mounts is also right there (pix 1) and my new springs are very close but I want IT! So, I think I have come up with this brand new idea, cut a hole in the frame and put a sleeve in, and then put the body bracket back on. Well, not so fast cowboy, after cutting the hole I search google and it turns out this is old hat, look at the cool exhaust passage kit. ( pix 4), Makes me feel better though.

So the question is; what will have most strength etc, the heavy pipe welded into the frame (Plan A no flanges) or two half pieces with flanges per each (tube type) frame rail bolted in like the kit (Plan B)? (or some combination of pipe and flanges “Work in Progress” ) Thanks.

,
,

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#2451056 - 02/12/18 10:32 PM Re: New Rotisserie and Plymouth frame cut for Dakota sub-frame. [Re: Old Ray]
poorboy Offline
master

Registered: 01/19/03
Posts: 6129
Loc: Freeport IL USA
I'm a welder by trade, my vote is for welding the sleeve.
The problem with bolting stuff together on a hollow box (like the frame) is is that you almost have to have a spacer inside the box at each bolt to keeping it from crushing the box frame (like it looks like your shackle bolts are doing). The advantage with adding the extra brackets to the frame is that it spreads out the load to a wider footprint. Bolting the extra plates on was just a way around welding them in place.

That said, after the pipe is welded into place, adding a 2nd plate to the inside and the outside, then welding the outside of those plates (I would weld all the way around the extra plate) would add a lot of extra strength. Your cutting a pretty big hole in the frame, spreading the load a bit more wouldn't hurt. Gene

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#2451110 - 02/13/18 08:01 AM Re: New Rotisserie and Plymouth frame cut for Dakota sub-frame. [Re: poorboy]
moparx Offline
master

Registered: 09/03/03
Posts: 8278
Loc: north of coder
i'm with gene on this. if you look close at the first couple of pics, you can clearly see the front spring mounts are crushing the sides of the frame rails, including the washers used under the bolt holes. this area needs welding of all the components in my opinion. this area of the chassis is highly stressed, especially after the exhaust cut out, so failure in this area must be avoided.
beer

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#2451492 - 02/13/18 09:53 PM Re: New Rotisserie and Plymouth frame cut for Dakota sub-frame. [Re: moparx]
poorboy Offline
master

Registered: 01/19/03
Posts: 6129
Loc: Freeport IL USA
OK. Old ray and I have been communicating by email. But just in case someone is following along and wants to know a good fix for this, I feel the need to include what I would do here. Understand, this isn't the only way, but its how I would do it.

He has removed the shackles. He will be using lengths of pipe just large enough for the bolts to pass through. If there are threads cut into the pipe, cut them off, start with full thickness pipe or tube. Grind clean all areas that will be welded, at least 1/2" all around the weld area.

Enlarge the shackle bolt holes on the outside of the frame (the non-shackle side), just large enough to insert the pipe through. It is not necessary to enlarge the holes for the shackle side of the frame. Through these enlarges holes, use a punch or a piece of pipe and be sure the shackle side of the frame is flat. It should tap flat pretty easily. You can use a flat plate against the frame to be sure you don't bend it too far.

Insert the pipe through the enlarged shackle bolt holes and be sure the bolts pass through without dragging on the sides. Be sure the pipe is square to the frame surface and bottomed out against the shackle side of the frame. Weld around the tubing for all 4 bolt holes on the non-shackle side of the frame, and grind the surface flat.

Weld the exhaust tube to both sides of the frame, leaving a little of the tube above the frame surface. Cut 2 plates, one for each side of the frame. With the close proximity of the shackle to the exhaust tube, I would at least extend the non shackle side out 1" past the shackle bolt holes. The shackle side either needs to be cut short enough to not interfere with the shackle mounting after its welded, or it needs to extend out far enough for the shackle to mount flat against it. If it extends out far enough for the shackle to mount on the plate, you will need to transfer the shackle bolt holes to the plate (I'll cover that later).


The thickness of the plates should be 1/8" or 11 gauge. Any thicker is a waste of material and is more difficult to work with. The plates need to extend out forward and rearward at least 1" (1 1/2" would be better) beyond the exhaust tube welded to the frame, and should match the top and the bottom of the frame. If it includes the shackle bolt holes, it needs to extend at least 1" beyond the farthest away hole (or however far you need for the shackle to lay flat without encountering the weld seam.

Then cut the hole to fit over the exhaust tube and the existing weld, and trim the plate to match up with the frame. Both plates will have to sit tight against the frame to be effective. If the shackle ends up sitting on the plate, I would do the shackle side first. Position the plate over the exhaust tube, align it with the frame, clamp it tight against the frame side and weld to the exhaust tube. Then weld all around the outside of the plate. With the correct size drill, use the shackle bolt hole spacers as a guide and drill the holes through the shackle side plate from the outside. Make sure the shackle bolt holes line up and you will be able to bolt the shackles on the frame. This is the time to "adjust" the bolt holes.

Once you know the shackle will bolt on the back side, remove the shackle, and follow the same procedure for the front plate, position over the exhaust tube, position the plate to align up with the top and bottom of the frame, clamp tight, weld around the exhaust tube. Weld around the outside of the plate, and drill the shackle mounting holes using the bolt hole spacers as a guide to drill the holes through the front plate from the shackle side. There will be no need to weld either side of the shackle bolt holes to the plates. Bolt on the shackle to the frame with grade 8 hardware.

Repeat the process on the other side. Gene

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#2451612 - 02/14/18 09:04 AM Re: New Rotisserie and Plymouth frame cut for Dakota sub-frame. [Re: poorboy]
moparx Offline
master

Registered: 09/03/03
Posts: 8278
Loc: north of coder
exactly how i would do it. up a little extra work, but well worth it in the end.
beer

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#2452720 - 02/16/18 04:15 PM Re: New Rotisserie and Plymouth frame cut for Dakota sub-frame. [Re: Old Ray]
Old Ray Offline
member

Registered: 09/20/16
Posts: 77
Loc: British Columbia, Canada
Anti crush sleeves and stiffening plate installed, I feel better now, thanks guys. (Bolts are just posed for the photo op!)

,img][/img]


Edited by Old Ray (02/17/18 09:53 AM)
Edit Reason: change pictures

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#2453790 - 02/19/18 01:05 AM Re: New Rotisserie and Plymouth frame cut for Dakota sub-frame. [Re: Old Ray]
poorboy Offline
master

Registered: 01/19/03
Posts: 6129
Loc: Freeport IL USA
That looks great! Good job! Gene

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