Frame connector install on a 2 post car lift

Posted By: Kern Dog

Frame connector install on a 2 post car lift - 01/24/15 11:28 AM

I've read before that it is advised to install frame connectors with the car either on a 4 post-drive on type lift or on jackstands with the weight of the car bearing on its tires.
I have also seen bare shells on rotisseries with frame connectors being added.
Soon I am going to begin work on a 65 Valiant Convertible. The owner wants some handling improvements including chassis stiffening. It currently is a roller with no engine/trans or interior in it.
I'm curious of any troubles I might encounter by doing the chassis stiffening while elevated on a 2 post lift. I'd think the lack of engine and trans would reduce flex with the car in the air as compared to a complete car. My thinking is that if the door gaps are consistant with the car in the air, it should be safe to install the connectors.
I plan to use 3x3 .120 wall tubing cut and boxed to sit against the floor, similar to those that I made for my brother in laws 72 Duster.

Attached picture 8406260-1-10.JPG

Posted By: FASTBACK340

Re: Frame connector install on a 2 post car lift - 01/24/15 02:29 PM

NEVER weld in sub frame connectors on a 2 post. Never.....

The load must distributed equally across the structure by either, as you stated, using a drive-on ramp lift or leveling and cross-squaring the rails and using 4 STURDY stands.

Once correctly installed you'll notice the difference. They really tighten-up the unibody.

Posted By: Copper Dart

Re: Frame connector install on a 2 post car lift - 01/24/15 02:42 PM

Quote:

NEVER weld in sub frame connectors on a 2 post. Never.....

The load must distributed equally across the structure by either, as you stated, using a drive-on ramp lift or leveling and cross-squaring the rails and using 4 STURDY stands.

Once correctly installed you'll notice the difference. They really tighten-up the unibody.

What troubles do you expect to encounter if you do it on the lift as he mentioned?

If you put the car up on the lift and the doors open and close properly I would say you should be fine doing it on your lift. I think it really depends on where you place the lift arms as to how much body flex you'll encounter. I did mine on the lift and the door alignment and gaps couldn't be better. They open and close just fine.

I did make sure the car, when lifted, was perfectly level before any welding took place.

Posted By: dvw

Re: Frame connector install on a 2 post car lift - 01/24/15 03:18 PM

During the 90's I worked at a GM dealer. We had a door hinge recall on Berretta's. If you did them on the hoist the door match would be off by 1/2". I can remember trying to open convertible doors on the hoist as well. They might open but seldom did they close. I wouldn't install them on a hoist.
Doug

Posted By: Challenger 1

Re: Frame connector install on a 2 post car lift - 01/24/15 03:24 PM

Quote:

I've read before that it is advised to install frame connectors with the car either on a 4 post-drive on type lift or on jackstands with the weight of the car bearing on its tires.
I have also seen bare shells on rotisseries with frame connectors being added.
Soon I am going to begin work on a 65 Valiant Convertible. The owner wants some handling improvements including chassis stiffening. It currently is a roller with no engine/trans or interior in it.
I'm curious of any troubles I might encounter by doing the chassis stiffening while elevated on a 2 post lift. I'd think the lack of engine and trans would reduce flex with the car in the air as compared to a complete car. My thinking is that if the door gaps are consistant with the car in the air, it should be safe to install the connectors.
I plan to use 3x3 .120 wall tubing cut and boxed to sit against the floor, similar to those that I made for my brother in laws 72 Duster.

IMO like you suggested. I think if your door gaps are good on the lift and good after the welding, then your good.

Like you said the motor and trans is out minimizing any flex to begin with, I would do it just as long as the car don't flex when you lift it off the ground, watch it closely as you begin the lift.

I did mine with the bare shell(coupe) sideways on my rotisserie and that was really easy. Everything fit on the car perfect when it went back together.

Posted By: 71rm23

Re: Frame connector install on a 2 post car lift - 01/24/15 03:54 PM

Quote:

Quote:

I've read before that it is advised to install frame connectors with the car either on a 4 post-drive on type lift or on jackstands with the weight of the car bearing on its tires.
I have also seen bare shells on rotisseries with frame connectors being added.
Soon I am going to begin work on a 65 Valiant Convertible. The owner wants some handling improvements including chassis stiffening. It currently is a roller with no engine/trans or interior in it.
I'm curious of any troubles I might encounter by doing the chassis stiffening while elevated on a 2 post lift. I'd think the lack of engine and trans would reduce flex with the car in the air as compared to a complete car. My thinking is that if the door gaps are consistant with the car in the air, it should be safe to install the connectors.
I plan to use 3x3 .120 wall tubing cut and boxed to sit against the floor, similar to those that I made for my brother in laws 72 Duster.

IMO like you suggested. I think if your door gaps are good on the lift and good after the welding, then your good.

Like you said the motor and trans is out minimizing any flex to begin with, I would do it just as long as the car don't flex when you lift it off the ground, watch it closely as you begin the lift.

I did mine with the bare shell(coupe) sideways on my rotisserie and that was really easy. Everything fit on the car perfect when it went back together.

All I have to add is this. I had to grind mine to make them fit to my liking underneath the car, to make it fit better to the contour of the floor is all. The doors open and close flawlessly. heck, even with one finger you can open and close my doors. I was worried and concerned about the geometry of the body flexing but not now with the way the doors operate

Posted By: Copper Dart

Re: Frame connector install on a 2 post car lift - 01/24/15 04:08 PM

Frankenduster, Consider that a 40 + year old car, especially a convertible, is sagging a little from normal use ( not to mention if it's ever been tapped/bumped in the past ) chances are that a bit of sagging should be expected. That being said, I would "unload" the body on the lift and check door to fender gaps as well as door to quarter alignment and ease of open and closing. You may help the car regain its "as new" geometry when installing sub frame connectors.
Just a thought.

Copper

Posted By: GY3

Re: Frame connector install on a 2 post car lift - 01/24/15 04:34 PM

I recently had subframes welded into my '63 and the difference was very noticeable.

We made sure and did it with the wheels all bearing the weight of the car.

The guy that did mine did it a little differently as I didn't want to interfere with the floorpans. He cut the front of the rear framerail out to where the 2x2 steel slid into it. The 2x3 that most people use is overkill for anything but a full on racecar IMO.

Posted By: Challenger 1

Re: Frame connector install on a 2 post car lift - 01/24/15 05:05 PM

Quote:

I recently had subframes welded into my '63 and the difference was very noticeable.

We made sure and did it with the wheels all bearing the weight of the car.

The guy that did mine did it a little differently as I didn't want to interfere with the floorpans. He cut the front of the rear framerail out to where the 2x2 steel slid into it. The 2x3 that most people use is overkill for anything but a full on racecar IMO.

with both of the above posters^^^^^^^

3X3" is huge, unnecessary and adds unwanted weight to the car, especially if it's a race car.

.120" wall tubing is pretty thick compared to the sub frames. Ideally you want connectors that are close in thickness as the original sheet metal. A little thicker but not twice as thick. IMO

It needs to be approached differently with and without the engine and transmission installed and whether it's a convertible top or coupe.

Posted By: Darius

Re: Frame connector install on a 2 post car lift - 01/24/15 06:43 PM

Hey Greg
I leveled my car on 4 bottle type jack stands that we're sitting on some 4x12 pads for extra clearance to roll under on the creeper. Once I had them tacked in place real good I put it on the rotisserie and finished the welding. I imagine you could do that on the lift. Key is making sure you are level with the initial tacks. My door margin issues were more a result of so many different donor parts like doors and panels from several different cars as well as a repop or two from AMD

Posted By: Kern Dog

Re: Frame connector install on a 2 post car lift - 01/25/15 12:28 AM

Thanks for all the responses. I mentioned the 3x3 because it was I used on my Charger. I suppose that a 2x3 with thinner guage would be fine for a small block Valiant.