Off the deep end, for fun

[Atilla the Fun]

Knowing full well what many of you think of me, but not giving a rip, here's a new thread for the new direction I've taken.
I'm doing very well fabricating custom hitches ( who knew there was so much demand? ) and that POS under the back of my T/A just isn't anything I could live with.
Recalling how I towed well over 2 tons with my '91 Camaro RS ( rated to half that with a proper hitch ) and my own towing was done via a half-arse install of a hitch I fabbed for an S-10,
I've started on a class 3 hitch for my T/A. Only that wasn't good enough. It has now morphed into including a gooseneck, and a whole lot of added bracing and other extra structure. Not counting the 1Le brakes, not counting the subframe connectors, and not counting a possible roll cage, and not counting the axle upgrade, I'm adding nearly 250# to the car.
But subtract 100 when I remove the hatch to use the gooseneck.
I figure I'm now good for towing up to 6,000 pounds.
Why? Because I know from experience that I can get a 350 to do 28 MPG at 60 MPH, not towing anything. My black S-10 did 28 at 70, but with a 140-HP 4.3L
Only I expect to do far better. Sure, a 6.0L LS2 with AFM, but not VVT, did 35 MPG in a 'vette. And the idea of towing with a 6-speed Z28 occurred to me in '94. Cruise empty in 6th, use 5th for towing, go to 4th on hills. But the lack of structure...so put the LS1 and T56 in an S-10? Too obvious. And sure, a magazine modified a Ram Cummins dually to 29 MPG, but only once. Also, not much difference between using the T56, versus just combining a custom converter with a 700R-4 and a tall axle gear.
No, I have a wildly different idea.
The 6.2 diesel was a non-starter of an idea, more for fitment problems than emissions laws concerning swapping a truck engine into a car.
But what about the much-maligned Olds diesel? It was used in cars through '85, making it technically legal for swapping into my T/A.
I had Don's C-10 6.2 do 35 MPG, so with less cubes and less drag, the Olds should see 40.
But it hasn't the output to move 10,000 pounds of car and trailer, up a 5% grade, at any speed above 20 MPH. It needs boost. It can't take much, but another 100 ft-lbs, at no cost to MPG when not towing...SOLD!
I've found a few different independent reports of the Olds doing 39-41 MPG in the big cars, with TH350c rather than 200-4R.
And it was made to go under a car hood, clearing a car crossmember, which is what the 6.2 wouldn't do.
I'm going ahead with the gas 350 SBC, because I have most of what I need, while I search for the right Olds survivor. Not many remaining. But there's a guy on the diesel place who has them, modified, in his work trucks, so they can do work under boost.
I haven't totally finalized my axle upgrade yet, nor my rear wheels and tires.
My ideal axle is from a '90-'93 454SS, on a pair of custom wheels, with 295/50R15s. Axle is rated to carry 4200, wheels to 2200 each, tires to 2060 each. But that axle is heavy. Using a regular 1/2-ton axle, rated capacity drops to around 3800, but still heavy from thick axle tubes. But less ring gear mass to try to accelerate.
Alternately, just go massive-overkill with the 10.5" FF 14-bolt from a non-dually 1-ton, get one of those fake-Testarossa body kits, and do a dually on 205/65R16 tires. Use some of those old-school Moon discs to disguise the wheels, and reduce drag. But there goes my MPG. And the gas 350 could pull this, but a turbo Olds diesel?
Maybe just do the dually, but only run the inner pair of wheels when not hitched to a gooseneck, and keep my MPG. Then, to ( mostly ) cover the outers, use the rear half of the wide-body kit from American Sportscar. Dzus them for easy removal when not running the extra wheels.
I'm still researching this, gathering measurements of the axles widths and such.
As for the Highway Patrol, who are sure to take interest, the gooseneck plate can hide under the carpet when I wish, toss an old work jacket over that ball. The rear hitch hides under the stock carpeted-plastic cargo-well cover. Basically, keep the whole deal invisible when not towing, but easily revealed for the Highway Patrol.
The rear hitch is now hidden behind the stock rear license plate, which is now mounted to a bracket that flips up. It does so in such a way that the plate is still centered, still read-able, but about 6" higher. This comes from the early '90s, when everyone was putting roll pans on pickups, and hiding those hitches behind the roll pans.
So, how many pickups, even the mini-trucks, can do 40 MPG empty? How many of them have the stability, killer brakes, and 4 seats? I count zero. None.
I may never actually tow anything with it, but I can't recall being so giddy in the last decade.

[Atilla the Fun]

The 10.5" axle was offered in 4 different widths. Taking advantage, there are off-the-shelf 16x8" wheels that will fit. Probably looking for 255/55R16s if I go that route.

[The Dark Side of Will]

Umm... Good to see you're staying busy.

Everyone here has something going on other than Fieros... Just be cool about it when you share.

I'm sure people think I'm nutz for working on an Eagle... 'tev.

[Atilla the Fun]

Dare to be different is great if it's for some real purpose other than just novelty. I love the Eagle build, even if I do differ on a few aspects.
This mutant of mine has made me feel a bit younger. I wake up looking forward to it like nothing else in recent memory.
I have a pair of 2.31" hitch balls for it, a 1" shank version, rated to 6K, for the rear, and another version with the 1.25" shank, rated to 10K for the gooseneck.
The rear of the roof is plenty far forward for steep driveways or other dips, even if I put the ball directly above the diff, which is at the front of the plate. I'm thinking I'll move it back a bit, to center it between the rear springs. These are the challenging decisions I struggle with in pioneering this idea that I expect noone will ever buy.
I knew I'd have issues with putting a ball directly above the fuel tank's sender access hole, and at present I'm leaning toward clearancing the tank with a big hammer, omitting the lock washer from the ball, welding the nut to the plate, and maybe welding the ball to the plate.
I hope to have it ready in time for the July 4th weekend car show, but I'm not holding my breath.
I don't have pics yet, only of me putting a bigger trailer behind my own pickup.
I'm pleased to discover that this hitch opens up more options for the exhaust tail-pipes. To match the legal ZZ4 conversion that GM developed, I would have to use Flowmaster's American Thunder cat-back, but I expect to find something else.
Still undecided on the axle, but I have researched the bearings. The '88-up C1500 8.5" has better bearings than the pre-'88, which is the same as the Ford 8.8". Good thing the yards always have plenty of '88-up C1500s in case I decide on this option. Crying shame I didn't save the 8.625" from my '06 Sierra. Only had 50K miles on it, too.

[CincinnatiFiero]

Are you going to build this, or is this purely mental masturbation?

[The Dark Side of Will]

I wouldn't weld the ball down... But do what you have to do to keep the nut in place.

I prefer hitch balls with female threads instead of a stud, but those are difficult to find these days.

Use the 12 or 14 bolt axle with stock F-body springs and airbags to bring the ride height back up once the tongue weight is over the axle.

The put ball over or even slightly forward of the axle centerline. If you put the ball behind the axle centerline, then the tongue weight is going to tend to lift the front end of the car.

I'm sure if you think about it enough, you can design a removable structure that will still allow you access to a fuel pump door. It would be a shame not to put one of those in with all the cutting and welding you'll have to do to the car.

[Atilla the Fun]

Thanks for the food for thought.
There's no in-tank-pump in this tank. Never was, never will be. Just a brand-new strainer I installed a few months ago. Carbureted '84, remember? '87 was the only year that the carbureted 305 F-body twins had an electric pump in the tank. The ZZ4's legality isn't affected by what style of pump is mounted where, just so long as the pressure doesn't flood the engine via the carb. I actually had that happen to me once, playing with my '88 IROC-Z. That one was factory-built with the base TBI V8. Like an idiot I used a dead-head style pressure regulator. Ever since that, I've gone to the extra trouble of rigging in a bypass-style pressure regulator whenever putting a carbureted V8 in anything having an electric pump.

[Atilla the Fun]

I checked again; putting the GN ball directly over the axle center won't work. It has to move back at least an inch. The spring centers are more like 2.5" back.
Maybe the solution is to use a much shorter torque arm? Jegs offers one, with or without an optional adjustability feature.

[Atilla the Fun]

Progress!
Removed the bumper cover and cut it, cut the plastic between the cover and the steel bumper, started cutting the steel bumper, ran out of blades, scraped all the glue over the seams everywhere I wanted my additions to touch the car, chiseled some spot-welded brackets off, and basically I can now attach the end brackets, test-fit the cross-tube and test-locate the GN plate.
I have pics, I'll upload when I can.

[Atilla the Fun]

Here are the first 3 pics. I'll upload more when my phone is re-charged.
In this first pic, I'm standing on the left side of the car, near the rear, looking down on the top of the sub-frame-rail. Notice how I've scraped away all the glue so that the new steel can sit flat

Now leaning in, standing a bit forward, looking toward the rear

Now same thing, but looking at the passenger side instead

[Atilla the Fun]

Notice I have the deck all scraped, hammered, and smoothed flat for the GN plate

[Atilla the Fun]

Here's as far as I got before I ran out of blades ( and drill bits )

and here's a close-up

[The Dark Side of Will]

I'm not sure the stock structure will be adequate for that.

I think everything between the springs and 5th wheel ball should be designed for this application. The vehicle structure was not. I would be looking to weld in new frame rail sections to take the tongue weight coming down from the ball into the axle.

There are removable 5th wheels for pickup trucks, right? IE, some mounts permanently installed in the bed that accept a removable structure which carries the ball. Are you thinking of using one of those?

[Atilla the Fun]

No, I'm not using anything you can mail-order.
First, on those rear subrame rails, I will put a pair of 12" lengths of 3" x 3" x 1/4" angle iron. Then across the tops of those I will set the 46.5" cross-tube of 3" x 3" x 1/4"-wall square mild-steel tube. This will be spot-welded. Then I will clamp the center-tail-tube under the cross tube, so I can mark where to cut the back wall of the trunk. Cut made, repeat for cutting the bumper. Now fit and spot-weld the tail tube. Pull the whole assembly, all 6 pieces, out for full welding plus gussets. Re-install for drilling. Make sandwich plates and drill those. Bolt the whole deal in place permanently.
Move on to the GN plate:
test-locate, drill 2 locating holes, bolt. Measure for final location of ball. Mark. Remove plate for cutting. Measure for cutting deck to match location of ball. Ball will also sandwich some of the deck. Plate back in, ball in hand-snug, 2 locating bolts in. Get underneath and drill up through car and through plate. Make, drill, and install sandwich plates.
Tie-in:
Install Competition Engineering cage per instructions. Add gussets. Weld to cross-tube, add bars to GN plate at rear springs. Add bars between cross-tube and rear of GN plate. Add bars from front of GN plate to SFCs.

Now the tongue weight, from either / both hitches, gets transferred directly to the tops of the rear springs, while the towing stresses get transferred to the rear trailing arms, which is what the axle pushes on.

[Atilla the Fun]

tomorrow afternoon I'll be stopping on my way home, to pick up a pre-fab tail-tube. The one the ball-mount will slide into.
And I think the cross-tube will be 2.5" rather than the 3" I typed earlier.

[Atilla the Fun]

As per this: http://www.moog-suspension-parts.com/Un ... prings.asp
I've decided on the 5664 up front, and the CC659 out back.

[Atilla the Fun]

I just got this; it's progress:

Tomorrow I'll do something with it.

[The Dark Side of Will]

It sounds like you're going to be adding things on top of the original structure.
I'm suggesting that you *replace* rather than add to the original structure... IE, section the portion of the original frame rails above the upper spring perches and replace with 2x4 (or whatever size is appropriate to mate up to the remainder of the original frame rails) square tubing of at least 1/8" wall thickness.

A lot of tongue weight on your fifth wheel is probably not one of the load cases for which the original structure was designed.

Also, if you have reasonable spring rates, your vehicle will either ride high unloaded or sag when loaded.
If you have unreasonable spring rates, your vehicle won't ride high or sag, but you'll hate life.

I strongly suggest and airbag system to augment the rear springs.

[Atilla the Fun]

I really appreciate you giving this your serious thought, then typing what you think.
Maybe I am setting myself up for failure.
To answer you, let me separate the 2 separate hitches, and just focus on the rear hitch first.
I think you're fully aware that my '84 T/A is practically / functionally / structurally identical to a '91 Camaro.
My '91 RS LO3 towed my mom's camper trailer, by itself well over 4000#, using just a basic class 3 that I fabricated for my first '89 S-10. It was NOT a decent fit in the 'maro, and I bolted it with 3/8" grade-5 all-threads with matching washers and lock-washers and nuts. No sandwich plates like this time. No grade-8 1/2" bolts like this time.
I got lucky with that, but the damage to the car was not obvious to anyone but me, and it was all behind the rear springs. No weight-distributing either, just dead-weight hitched. The sides were just a pair of 4" by 4" by 4" by 1/4" angle iron, as inners. The new is getting 3" by 3" by 12" by 1/4", inners and outers.
The 'maro was rated to tow 2000.
I intend to make and sell copies of my class-3 rear hitch. It must be removable as a unit. Thus no grafting it in to the car's structure as you propose. Besides, what if my car gets T-boned? Finding another F-body is easy. Re-doing all this, versus just transplanting my original? The answer is obvious.

Moving on to the GN, let's consider my '79 C-20 that I bought from my landlord. In the bed I found a GN ball, about 6" behind the rear axle center-line, attached through a plate of 3/8" mild steel. That plate was spot-welded to the fifth-wheel hitch stuff, which was bolted to the bed. There is 1 bracket per side, with a single bolt to the 5er hitch, and a single bolt to the frame. Under the bed there's a 4-foot length of 3" C-channel. The ball goes through that. That channel is actually crooked about 5-10 degrees from longitudinal, and held in place by nothing but the ball / nut. With this Scott towed 20K repeatedly. I'm using 1/2" plate for just 6k, that problem is solved.

So here we have precedent. Recognizing the concerns, I've addressed them.

I listed the Firestone air bags for when I'm hitched. I'm springing for non-hitched.




More progress: I found a free, full-floating, 8-lug, SRW Dana 60 axle for the dually portion of this project! The catch is the work I have to do in trade, and the 4.10:1 gears in it, instead of the 3.54:1 I want. But since Strange Engineering offers their bolt-in S-60, I know this center-section ( differential housing ) is not too monstrously large to clear my stock-style rear suspension, stock-style exhaust, and my stock fuel tank.
These truck tubes are larger than the S-60 uses, so I'll have to contour the brackets accordingly.
As for the torque arm, I discovered I don't need to fight that. Five7kid on TGO tried some trailing-arm deal that eliminated the torque arm. He didn't like it, but he wasn't building for tow-and-show.

[Atilla the Fun]

Progress!!
Today I got the all the steel for the "bumper" hitch. Mock-up pics within 48 hours.