I am less concerned with the siz of the steel than with the geometry. I weas hoping someone could tell me where the center of gravity is so I can set the center of the pivot. I want to make sure it doesn't try to rotate on me when I don;t expect it.

Thanks in advance,

How's this?
http://www.roadglue.com/wiki/index.php?tit...r_a_Porsche_914

Those are fantastic!

Automobile Atlanta sells some plans too. I have seen them and as I recall they involve the use of two engine stands modified into a rotisserie.

Yep and they charge you 16.95 for photo copies of it and the picture is quality is excellant

Here's the AA plans. There are on the AA website.

And now for something completely different.... The Octisserie

http://forums.pelicanparts.com/porsche-911...rotisserie.html

And I was thinking a 7 pound pork roast ..............................

The Cap'n

Hmm, Boston butt/ pork shoulder/pulled pork!!!!

Thank you everyone! From the looks of it the center of gravity is about the centerline of the bumpers. Thats a big help!

Mine is based on two extended engine stands, and it is very easy to rotate the car. I made mine relatively low so that it could roll into the garage with the car in a vertical position -- and I only have about 1/2" from the outside of flares that I just finished installing (whew, I measured correctly oh so many moons ago!!!). However, I cannot rotate it 360 degrees, because the windshield corners would hit the connector. See post #17 in my build blog for details:

http://www.914world.com/bbs2/index.php?sho...by++rustoration

You can see the car in my avatar, too. Good luck with your rotisserie project!

Geoff

Exactly. That is the CG. And they are easy to make. They make a great "learning to weld" welding project - so long as you have done some practice first and your welds are sound. You can get the engine stands from Harbor Freight cheaper then you could buy the steel parts to make it.

I bolted mine directly to the 75/76 bumper shocks mounts. Making a mounting plate for early bumpers would not have been hard at all to do.

The cross beam down the middle is critical for stability. It ONLY has the be tall enough for the car to clear the cross beam at the bottom for the full 360 rotation. Higher then that and it starts being difficult to work on.

You can see pretty easily where I used the engine stand, and where I used steel stock. I asked the same questions you are asking now, and looked at the same plans. IN the end, I discovered it was easier to just make it.
I put mine on casters, and there were several times where I rolled it out of the garage for whatever jobs needed to be done. It was very sturdy. And when I did not need it any more I sold it for a small profit.




Zach

The plans/directions on Road Glue are excellent!

Those weren't there 10 years ago when I built mine. Here is my drawing. The drawing was never was completed, but it was good enough for me to build mine from.


Click to view attachment

Thanks!

I put those up there because when I built mine I had the same problem as everyone else. There were no published plans. Well the AA plans were published, but if I remember correctly (haven't looked at them in years), they were a bit thin on details.

I am glad people find the plans workable. I am still using mine. And I have received a few emails from people who have built using the info on the wiki.

PS: My plans are simple but the CG is not exactly through the axis of rotation on my setup. It is pretty close and it's pretty easy to rotate. But the car wants to lie upside down. So you do need to lock it into position (which I think you would need to do with any rotisserie even if the CG is through the axis of rotation.

On the one that I built, it would hold any point in the rotation without using the locking pins, and turned very easy w/o pulling at any point in the rotation. This was not designed, it was a happy coincidence. But I used it all the same.

It MAY be just a 75/76 thing, as I am not exactly sure where the early bumper mount. I just laid the beam on top of the bumper mounts and bolted it on, and that happened to be so close to the axial CG was that the car was stable at any point of rotation.

What I can say, though, was that it was SO handy to be able to put my car on its side and push it out of the way when I needed space in my shop for another project. I wish I could store my fully built car that way over the winter!


Zach

Thats interesting about yours Zach. I hadn't thought about the early/late bumper mounts (I know the bumpers are different, but how different are the mounts?) Anyhow, mine is a 72 and the center of rotation is right through the bumper mounts and it seems top heavy, but not by much. I am missing some metal on the lower part of the body (still doing some body repair) so that might account for some of it.

You are absolutely right about it being nice to rotate it onto it's side and then slide over to make space.

It may be as simple as whether you take out the windshield or not...

Zach, do you have some close up shots of where you attached to the bumper mounts?

I don't. It was so easy that I never thought to document it.
all you need to do is picture the 75/76 bumper shocks. The attach to the bumpers with a C bracket. I filled the bracket with washers for strength and just bolted the arm of the rot right to it. Here is a little MS paint that I just drew up to explain it better.
Click to view attachment

If you look at this picture, you can see that the cross arm is just bolted directly on top of the bumper mounts. Its is just that simple. The shiny bits under the arm are the reflection off the washers I used to support the C bracket. Also you can see that it is perfectly happy sitting where it is without the locking pin in place on the engine stand


On this picture you might be able to see it a little more clearly. This is while I was test fitting.


One more. This one shows the attachment from the side. Wish I had remembered this picture before I made the little graphic.


If you have an early car, you can't mount it this way. But on the late cars, the shocks are long enough that mounting is dead simple.
Zach

Thanks, Zach! I have a late (76) car with early bumpers. I will have to score some bumper mounts again, as mine went bye bye.