Builds 86 Xtra Cab Build (4Wheelunderground 3 link front, 4 link rear and 3.4 swap) (4 Viewers)

[aztoyman]

Looks like I need to hole saw THROUGH my engine then. I'll get pics when I'm done. . Give me some ideas BEFORE I drill guys.

 

[ntsqd]

Just make the engine load-bearing and part of the chassis structure.

If there were room, going around the rear would be better than in front, but there's no there, there!

However the overhead view has some good news. The suspension's force acting on the towers can only ever be inline with the shock shafts. The leverage that those forces have on the frame is always 90° to their "Line of Action" (which is along the shafts). The shafts are not very far out from the sides of the frame rails, making their leverage against the frame pretty low as the height of the towers doesn't mean a lot. This means two things, you're less likely to need that tube over the top of the engine, and conversely, the more effective that tube will be.

 

[aztoyman]

I was going to see if I can find some tube made of unobtanium and use that. But, what NT just said tells me maybe I don't have to.

Would what I have made of.250 wall be worth my effort? Or just use nothing?

I APPRECIATE everyone's input as always.

 

[Broski]

I’m guessing you don’t need that brace for what you’re doing with your truck.
Lots of guys running the same kit on a 80 without the it and there much heavier.
What Does 4 Wheel underground say do they recommend the brace ?
That being said what you have has to help some.
What about using .250 Dome that should minimalize the flex .

 

[aztoyman]

@Broski I wasn't told anything about adding it from 4WU. I just remember being told I might have an issue way back when I put the steering shaft through the shock tower. That the flex might bind my steering shaft. That is my main reason for trying to add this brace. Well, that and I like stuff sticking through the hood. A supercharger would be cooler though.

 

[aztoyman]

I took some measurements and even if I put this brace on, it should fit under the scoop I'm considering.

I don't really want to put it on if I don't have to so I'm going to save my parts in case I change my mind. That will be decided if and when I get evidence of contact on the steering shaft once I get it in the dirt.

 

[aztoyman]

I decided rather than buying a new set of OEM style marker lights and modifying them to also be turn signals, I'd just get the cool ones @ToyotaMatt offers. Here's a preview. The grill and lights are just kinda hanging on without screws.

 

[gnob]

I decided rather than buying a new set of OEM style marker lights and modifying them to also be turn signals, I'd just get the cool ones @ToyotaMatt offers. Here's a preview. The grill and lights are just kinda hanging on without screws.

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still can really wrap my mind around why na didn't get these.
wish i could have gotten my hands on some oe ones. it was ghey modding a brand new part to fit the oe bulb holder.
i assume your holder matches the housing properly?

 

[aztoyman]

Matt included the bulb holders and LED bulbs in these light housings. You can see them in the one pic that shows the backside. I don't have the proper connector on my truck harness but Matt has them on the way.

 

[gnob]

i couldn't justify his pp. im in like $55 and an hour.

 

[aztoyman]

Definitely on the pricey side. Plug and play once I get the connectors. ( Included but not shipped with the package by mistake) He got right on it though. My daughter covered it for my Christmas gift.

 

[Broski]

@Broski I wasn't told anything about adding it from 4WU. I just remember being told I might have an issue way back when I put the steering shaft through the shock tower. That the flex might bind my steering shaft. That is my main in in reason for trying to add this brace. Well, that and I like stuff sticking through the hood. A supercharger would be cooler though.

On the 80s you have to make the same notch for steering shaft, the ones I have seen they do the half pipe thing, yours look much stronger boxed out the way you did it. I don’t think you’re going to have any issues.

 

[bkg]

The tube will help - a lot. It may not be ideal, but you have tight spaces to package something. I would absolutely do it.

I used the old panhard from the All-Pro kit on mine. Bolted to the top of the towers. It absolutely makes a difference. Hindsight, I'd skipped the 4WU towers and done tube (i'd also have stayed w/ 12" CO's) as it would have made packaging much easier. Horrible picture - this was when I was trying to figure out if I could make a ibooster work.

 

[Broski]

The tube will help - a lot. It may not be ideal, but you have tight spaces to package something. I would absolutely do it.

I used the old panhard from the All-Pro kit on mine. Bolted to the top of the towers. It absolutely makes a difference. Hindsight, I'd skipped the 4WU towers and done tube (i'd also have stayed w/ 12" CO's) as it would have made packaging much easier. Horrible picture - this was when I was trying to figure out if I could make a ibooster work.

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Your tube has hardly any bend to it

 

[bkg]

Just make the engine load-bearing and part of the chassis structure.

If there were room, going around the rear would be better than in front, but there's no there, there!

However the overhead view has some good news. The suspension's force acting on the towers can only ever be inline with the shock shafts. The leverage that those forces have on the frame is always 90° to their "Line of Action" (which is along the shafts). The shafts are not very far out from the sides of the frame rails, making their leverage against the frame pretty low as the height of the towers doesn't mean a lot. This means two things, you're less likely to need that tube over the top of the engine, and conversely, the more effective that tube will be.

the frame will still twist. It's not a huge issue for the purpose of this build, but it certainly won't hurt to add the bracing. Could possibly go in front of and behind the intake manifold to add more tube...

 

[bkg]

Your tube has hardly any bend to it

It's doesn't have an large bend, but it's also not mounted as "correctly". Plus, I had to hack out 1/3 of the tube to clear the center hood brace.

Neither truck has ideal bracing. I'd still not hesitate to do what the OP designed.

 

[aztoyman]

@bkg Thanks for your input. I realize that my cross brace is not ideal. I'd have to think it would offer SOME support regardless.

 

[ntsqd]

the frame will still twist. It's not a huge issue for the purpose of this build, but it certainly won't hurt to add the bracing. Could possibly go in front of and behind the intake manifold to add more tube...

I don't see it helping as much as you seem to think that it will because all it does is make a square structure. Anchor the two bottom corners of the square and push on one of the top corners. It will still distort from the push. If the tube could be straight then it would essentially double the strength of the structure because now both towers are resisting that push, but because the tube has to have two large bends with long legs below those bends the tube itself will flex before the rigidity of the opposite tower comes into play.

And all of this assumes a lateral push, which is not possible because the forces on each tower can only act along the length of the coil-overs. Being that they are nearly vertical, the only forces that can be applied to the top of each tower are also nearly vertical. If we want to get into Vector Math we can break down just how tiny any horizontal component of that nearly vertical force will be.

So then look at those vertical forces. The tube isn't oriented in a direction to be of much help there either. The ends are pointed down, so maybe that would do something, but then there's those large bends that will flex under that loading. We're back to it being a parallelogram structure where the only way to make it really stiff would be a diagonal thru the engine block. Push on any corner in any direction and the whole thing distorts. Building those lower corners to be as rigid as possible is the best bet. I'd sooner put in structure under the oil pan, if even possible, to further tie those lower corners together.
Or build an engine cage so that these forces can more easily be routed around the engine.

 

[bkg]

I don't see it helping as much as you seem to think that it will because all it does is make a square structure. Anchor the two bottom corners of the square and push on one of the top corners. It will still distort from the push. If the tube could be straight then it would essentially double the strength of the structure because now both towers are resisting that push, but because the tube has to have two large bends with long legs below those bends the tube itself will flex before the rigidity of the opposite tower comes into play.

And all of this assumes a lateral push, which is not possible because the forces on each tower can only act along the length of the coil-overs. Being that they are nearly vertical, the only forces that can be applied to the top of each tower are also nearly vertical. If we want to get into Vector Math we can break down just how tiny any horizontal component of that nearly vertical force will be.

So then look at those vertical forces. The tube isn't oriented in a direction to be of much help there either. The ends are pointed down, so maybe that would do something, but then there's those large bends that will flex under that loading. We're back to it being a parallelogram structure where the only way to make it really stiff would be a diagonal thru the engine block. Push on any corner in any direction and the whole thing distorts. Building those lower corners to be as rigid as possible is the best bet. I'd sooner put in structure under the oil pan, if even possible, to further tie those lower corners together.
Or build an engine cage so that these forces can more easily be routed around the engine.

I think you're kind of correct, but only on paper. Unless the shock is 100% vertical... and in line with the center of the frame... (which is not possible in this situation). there will be a lateral force on the tower... And the frame can twist.

Likely will never be enough to worry about, unless there's some high-speed activities involved, but it still happens.

 

[bkg]

@bkg Thanks for your input. I realize that my cross brace is not ideal. I'd have to think it would offer SOME support regardless.

IMHO, there's zero reason to not do it. Even if it's only for peace of mind or because it looks cool.