Home Built Body Rotisserie

[kwilford]

A while ago, I decided to build a "body dolly" for my Opel GT, since I had removed the suspension while restoring it, and the lack of being able to move it around was a great big pain in the butt. That thread can be found at:

http://www.opelgt.com/forums/2d-body...ody-dolly.html

At the time, I lamented that what I REALLY wanted was a rolling rotisserie, but I didn't think I had the fabrication skills, nor the room in my garage. A year and a half later, while I found the body dolly to be very handy, I was at a stage in the restoration where a rotisserie was almost mandatory. Frankly, if I was just content with a "good" restoration, the dolly was fine. But when I decided to get the shell media blasted down to bare metal so I could be sure that ALL the rust was properly repaired, a rotisserie is the only way to go.
So, I did a bit of research on the Internet. I also talked to some body-shop types who did restorations. Here is what I found:

1) Rotisseries are commercially available, for about $1500 to $2000 USD (add 15% to $CAD)
2) Some commercial units are more "home-built" than "commercial"; you get what you pay for
3) REALLY good units are big, bulky and take a lot of space, as they usually stick out from the ends of the body
4) A GT is a LOT lighter than a '64 Impala, so the bigger rotisseries are over-kill for what I needed
5) There were a number of pretty well documented home-built body rotisseries on the Internet, some better than others, but none quite fit my order.

That order was (or became, as I educated myself):

1) compact and light-weight
2) mobile, but not so much as to load on a trailer with the body in place (I had the dolly for that)
3) raisable, as I determined that fixed-height rotisseries were pretty limited in use
4) collapsible, or at least unboltable, as it had to be stored SOMEWHERE at my house when I was finally done this car (or until it was attached to the SportWagon!)
5) Cheap, or at least not as expensive as a commercial unit.

Here are some of the commercial units I saw, and some links in case you are interested:

Carotator - The best value in Automotive Rotisseries
Accessible Systems manufacturers of auto rotisserie and accessory tools for vehicle restoration
GTO
Auto Rotisserie Info

[kwilford]

I also saw some pretty neat home-built body rotisseries. Some were pretty simple, and not much more that engine stands with brackets to attach the body or frame to. One of the first I saw, as shown below, was built by my brother Laurie, who has restored a couple of Austin Healey 3000's. This has his recent '65 BJ-8 restoration on it a couple of years ago, and he is now using it for a '56 AH 100-4. Those are pretty darn light, especially until the fenders are centre shrouds are installed, so I wanted something a bit "beefier".

I have also attached photos of a few others I saw on the Internet, and here are some links

Body Rotisserie
MOWOGMAN's Home Page
Rotisserie
rotator
http://www.zparts.com/zptech/article...ley/index.html
New Page 2

As you can see, some of those are pretty sophisticated, while others are less so. A couple even had Opels on them! My search continued...

[kwilford]

Here is another home built rotisserie with a GT in it, and Mathew Newman's GT on Keith Lundholm's Whirly Jig rotisserie, currently being restored and documented elsewhere on this site. Keith provided me some helpful ideas on attaching the rotisserie to the GT body when that came up

[kwilford]

One of my criteria was that the rotisserie be "cheap", so making something as sophisticated as a Whirly Jig wasn't going to happen. One home-built that I liked was the last link above, but it was still too big and bulky to fit my garage space.

One I liked for compactness, and for using a readily available engine stand as the starting spot, is at

Body Tub Rotisserie

with plans at

Spitui!

The photos are below. What I DIDN'T like was the lack of being able to raise it (although I didn't figure that out until I started fabrication) and the inability to fully rotate the body without tipping. I'll get to the raisability thing later, but the full rotation problem was obvious: he didn't have the body balanced at the pivot point, and the base was too narrow.

[kwilford]

So here I was at the starting spot. I made up some sketches of what I thought would work, pulled my engine stand out and bought another one just like it ($40 at Princess Auto), and set it up next to the GT, mounted on the body dolly at the height that I determined to be required to let it fully rotate.

The first thing obvious was that an engine stand is too short. It works if you only want to have the body half-rotate such as the Spitfire rotisserie, but in order to fully rotate, two things are required:

1) the pivot point must be EXACTLY (or very darn close) at the centre of gravity (side to side, AND top to bottom). The first is easy, but the second is harder to figure out. I found I could closely estimate the CofG by "eye-balling", but I was still out two inches. A lot, unless a mechanical rotator and a serious lock device is incorporated, and I wanted simple.

The final balance point was found by trial and error, at about 2 inches higher than the front bumper body seam, and an inch above the licence plate bolts. This is with the body shell pretty bare, except I still have the doors attached (for now). I don't think it will change much with the doors removed. If you have left some pieces attached (interior, glass, differential etc.) the balance point will be in a different place. Better commercial rotisseries incorporate a sliding adjustment to set this after the car is set on the rotisserie. Mine uses a couple of vertical bolt hole choices.

2) that pivot point must be at least 40 inches above the ground, otherwise the body sides hit the cross bar. That height works for a GT (they're narrow, in case you hadn't noticed), but anything wider (even the aforementioned Ascona SportWagon) needs the pivot higher. I finalized my maximum height at 48 inches.

I discovered that the Spit rotisserie had "cheated" by installing the pivoting castors (replaces the side "fixed" castors so it can be moved sideways) to overcome the "lean" built into the engine stand. I tried to see if I could use it like that, but I didn't like 1000 pounds of steel balanced on a leaning device. I also didn't like how narrow the standard stand was. It was only 30 inches wide, and I decided anything pivoting at 48 inches needed to be 48 inches wide. See the photos below

[kwilford]

First thing was to straighten out the leaning post, and to incorporate some kind of extension capability. The first photo shows the chop saw about to sever the standard engine stand post from the base. I then straightened out the angled post base.
The next photo shows the replacement cross bar, 48 inches wide, with swivelling castors lifted just enough to level the stand, and details on how I raised the castors.
Next is a 2"x4" piece of rectangular tubing about to be welded as the new fixed post. The old post would slide inside this post. I pulled this 2x4 from the metal shop's scrap bin (a tenth of what it would have cost), so it wasn't QUITE what I wanted; it only had 1/8" walls, rather than the 1/4" I wanted. The standard engine stand post is 1 1/2" x 3 1/2", so the inside dimensions of the fixed post were a bit too large. I will show how that was overcome in the next post.
I considered fabricating a brand new base (and even a new post), but I had decided I still wanted to use them as engine stands when the GT wasn't pivoting around the garage. I even left the stands set up so I could use the old 30 inch wide base rail, rather than the new 48" rail. As a result, I went to a bit more trouble than I might have just to save me $80 on two new engine stands. Oh, and the space to store them...

[kwilford]

I had already figured out that a couple pieces of 1 1/2" by 1/8" angle iron would nicely fill in the space between the sliding and fixed post. They would also strengthen the sliding post. Fortunately, the way they installed also alleviated a problem with the new 2x4 fixed post: it had an internal weld seam sticking into the inside, so the space between the angles allowed the seam weld to clear.

So, I had now figured out how to slide the pivot up and down. I had planned to just do it manually, as in set it to the height I wanted by either an engine hoist or just mounting it at the desired height. The final photo shows the posts extended and retracted, but I decided I didn't like the "manual" method of raising and lowering.

[kwilford]

OK, now I had to do something I DON'T like doing, which was to engineer a new design feature (adding a device to raise the pivot post) into an existing design. I looked at a number of options, including a similar trailer screw jack as I had used for the body dolly. Instead, I found a suitable hydraulic cylinder at Princess Auto (3000 lbs, 22 inch lift), and for pretty cheap ($59 CAD). But I had already finished the major design, and I hadn't incorporated a spot for the cylinder.
My preference would have been (and still is) to mount it at the front of the stand as shown in the commercial rotisseries, so the car body weight is directly and squarely supported by the cylinder. But I didn't have enough height at the front, and the pivot tube for the engine stand was too short, so I compromised and attached the cylinder to the side. It actually works VERY well, once I got it perfectly straight and true. At first I had the cylinder a bit slanted, and it jammed as it extended so it wouldn't easily retract. In some ways, it works better, as the jack handle is at the back, instead of at the side. The following photos show the mounting details.

[kwilford]

Once I had the basic rotisserie built, I had to figure out a way to attach it to the GT body.

The front was actually pretty easy, at least for my GT, since it is pretty rust free and the frame rails for the front bumper were in good shape. I wanted a longer attaching rail than the standard bumper mount, so I extended it as far into the front, under the headlight bucket, as I could.

The front rails started off as 1x2 rectangular tubing, but I realized that they weren't strong enough when loaded sideways. I could have replaced them with 2x2 tubing, but instead I doubled the 1x2 up and welded them at the seams. This was only 0.095" wt tubing. so the doubled-up inner wall helps make them stronger than if they were 2x2 x0.095". I really should have used 2x2x0.125" or even 0.188" (I think 0.25" is overkill for the GT's weight), but I used what I had. I used 2x2x0.188" tubing for the cross bars on each end at the rotisserie, but most of the 2x2 is 0.125" thick. Except the bar that runs lengthwise from front to back, which is 0.095" wt. Again, I got this cheap (from the scrap bin) but I used proper hitch 2x2 material, which has a smooth (no internal weld seam) 2 inch internal diameter, to connect the two pieces to the stands.

Then I added a key element, in the form of an additional mounting bolt on each side. I drilled it from inside the engine compartment (there isn't an engine in there, of course), and then through the attaching rail. I used 3/8" inch Grade 5 bolts and heavy washers. Here are some photos

[kwilford]

I had an idea for mounting the rear, using the rear bumper mounts similar to the front. But the internal frame rails don't really properly connect to the bumper mounts, and because they are flush to the tail panel, I was concerned about vertical loading.
I used 1/2" Grade 8 bolts inside heavy wall 3/4" tubing as spacers. It worked, but not to my satisfaction. I wanted the cross rail to be further away from the body to be able to media blast and paint the tail panel, but longer spacers and bolts flexed too much.
The following photos show my first design, but the second method in the next post is much better

[kwilford]

Here is what I finally did, thanks to Keith Lundholm's suggestion. The 1x2 cross rails inside mount to the spare tire shelf mounting brackets, and the 2x2 rails stick out the tail-light holes. I reinforced the factory welds from the shelf brackets to the unibody rails, and added small welds to the inside wheel well panel to make it stiffer in side load.
I used the factory front 8 mm bolt holes, but drilled new 1/2" holes for 1/2" bolts at the extreme rear of the shelf brackets. I am still a bit nervous about only using the 8 mm bolts for the front mounting holes, but I used grade 8.8 and bumper washers to give it maximum strength.
Virtually all of the other mounting bolts in this design are 1/2" grade 5 or grade 8, and I used grade 8 nuts almost everywhere. I think a 1/2" Grade 5 bolt has a tensile strength of 5000 lbs, and the Grd 8.8 8 mm is something like 1500 lbs, so I shouldn't worry. And I don't as much, now that I have done the strength calculation

[kwilford]

Here are a few other design details. I added angle iron braces to the fixed posts on the stands, and used the aforementioned trailer hitch 2x2 internal diameter square tubing with 1/2" clamp bolts to mount the lengthwise bar. To mount the lengthwise bar to the end stands, I moved the castors on the engine stand bar back one set of holes to allow the tubing to slide over it a few inches.

There are a few designs out there without the lengthwise rail, and a few with dual rails (such as the Whirly Jig). I wouldn't even THINK about not having the length-wise rail, as it equalizes the bending load placed on the body. When I first lifted the car on the end stands, they tipped up a bit, indicating that the body was the only thing keeping it all from folding up like a cheap kite.

The dual lengthwise rails are nice, as they support the load much better and are stiffer in sideways bending than the single rail. If I wanted to move this around more, such as onto a flatbed trailer for transporting, I might add a pair of side rails. But for moving it around the garage, the single rail is fine.

[kwilford]

And here is the final product. It mounts up very easily with the body only about 18 inches above the ground (about the mid-point of my body dolly height) and then raises another 22 inches if I want. I find that a comfortable height is about 45 inches at the pivots, and it could be even 6 inches lower and still clear the length-wise bar. I lubricated the sliding post and the pivots with "Fluid Film" after painting it all with TremClad aluminum paint. I drilled 1/2" holes every 2" in the sliding post and use "hitch pins" to lock it at height. I also used 1/2" pins to keep the engine stand tube from sliding out of the pivot tube. The hydraulic cylinders lift it easily, and it slides down smoothly when the valve is opened. I can rotate the body easily with one hand. To secure it at a certain tilt, I welded 5/8" nuts on top of the stands (where the lock pins normally go), so I can either use the pins at the pre-drilled holes (about every 30 degrees), or use a 5/8" bolt to lock it at whatever angle I choose.

I hope that you found this informative and please ask if you have any questions.

[Rino]

Very Impressive! I have been contemplating building one of these for few months. And you have answered the few questions I had been running up against. Thanks for taking the time to post your build up.

[saxybiker]

When I have to do another body restoration, I really wanted a rotisserie. This looks like something I could build myself. Thanks Keith for sharing your expertise. I even have the requisite 2 engine stands to start with. Now all I have to do is to finish the rebuild of both the engines that are now on those stands!

Thanks again!

Allen

[ftl]

Very nice Keith. And very nicely written up. Keith was showing his invention off to members of our local car club on our spring garage tour today and everyone I saw (including me) was impressed.

[maglinjosvinn]

i'm back to working on my GT after a 2 month 'distraction' and i got a slight problem... my stock for building my rotisserie is at my work, while the car is at home... i really want to get this 24 ft bar of sq tube cut down, but i don't want to screw myself by cutting too short... is there any dimensions on the peices that ... 'fork' into the front and back? i need lengths because i have great cutting solutions here at the shop and none to speak of at the house. i reply here because of the rotisserie in the 4th/5th replies that was home made... thus far i'm modeling my own after those images.

[Sparky73]

I am thinking about building one of these myself. I've just got to pull the motor on my GT before I start body work.. and this will help a LOT.

I should be able to get SOME free supplies from either the shop I work at, or my dads. For anyone who has built one, about how much money was put into it?

[2 Fast 4 U]

......For anyone who has built one, about how much money was put into it?

It only costed me the money for the paint that I used, for the materials, I was sponsored bij my boss [he didn't know], for the welding, I got that done by my brother at his work, and the bearing houses with axles [the things on top to rotate the car easier], my father had those lying around for years, maybe decades. here some pic's

[kwilford]

For anyone who has built one, about how much money was put into it?

In my case, I had to buy most everything. In no particular order:

1) Engine stands: two at $40 ea
2) Hydraulic jacks: two at $50 ea
3) steel: about $150
4) Casters: four at $10 ea
5) Welding wire (flux core): about $60
6) Hardware (bolts, etc): about $30

So all in about $460 CAD, which at the time was about the same in $USD.

HTH