Chevy Nova Forum banner

1 - 10 of 10 Posts

·
Premium Member
Joined
·
2,161 Posts
Discussion Starter #1
I want to make sure the subframe of my convertible is straight, and then add subframe connectors to make sure 'vert doesn't sag as it ages further. I am not confident enough in my skills, yet, on this kind of adventure. There is a great frame shop just down the road that I know does custom frame work. If I take the car there, what exactly should I ask for so that the project comes out right, the panels stay straight, and the doors open and close correctly? Please give me some ideas?

Thanks,
Ed
 

·
Premium Member
Joined
·
882 Posts
It's called unibody

Frame shops do not usually work on these cars. The ones I'm aware of deal primarily with trucks in this area because they have a full frame under them.
Your conv. is a unibody car and it usually takes a good body shop to work on the alignment of a unibody car.
The car is held in place by a combination of the roof and floor. Your car, when the top is down only has the floor that is why it is critical to the cars alignment. The other means of support is sometimes called a torque box, it is the area just inside the rocker panels on each side of the car. These area's are critical to the structural support when the top is down.
I do not want to try and get to technical here because I'm not a body man and have never done the work myself. I'm sure there are guys out there that will describe it differently than I do.
In your floor pan there are special braces that were only used in the conv. If these braces and/or the inner rocker panels are rusted through, it will take a very experienced body man to rebuild them and I believe it will be very labor intensive. If they are not completely gone, someone may be able to repair or replace them in order to bring the geometry of the car into spec.
My suggestion is to look for an experienced bodyshop to give you an estimate or there are some relatively new places out there building full frames for these cars and that may be the most practical way to salvage the car.
I hope this information helps.
 

·
Premium Member
Joined
·
2,161 Posts
Discussion Starter #3
Thanks Fore-speed.

I think the floors on the car are solid, no rust, as are the rocker areas. I'm just looking for additional structural support.

-Ed
 

·
Premium Member
Joined
·
882 Posts
Structural support

Rich Bickle's place in Wisconsin is making a full frame for our cars for $3500. You could use a stock suspension and save tons of money over all the add- ons like coilovers and disc brakes.
The ultimate support would be a full frame.
 

·
Premium Member
Joined
·
2,161 Posts
Discussion Starter #5
Fore-speed,

Rich Bickle's frame is outstanding...but expensive. The frame doesn't use the stock suspension components. The price for frame only is $3495.00. By the time the necessary suspension components are added, plus Ford 9" rear, it comes to $13,600.00 before bolting the wheels on. I really wish I was in a place to afford that....not now. Thanks for the info.

-Ed
 

·
Premium Member
Joined
·
4,612 Posts
I want to make sure the subframe of my convertible is straight, and then add subframe connectors to make sure 'vert doesn't sag as it ages further. I am not confident enough in my skills, yet, on this kind of adventure. There is a great frame shop just down the road that I know does custom frame work. If I take the car there, what exactly should I ask for so that the project comes out right, the panels stay straight, and the doors open and close correctly? Please give me some ideas?

Thanks,
Ed
hi ed.
i own a 63 ragtop AND a frame shop,so i might be able to offer an opinion.
i have done exactly what you've suggested and it did make a noticeable improvement to body flex.
the truth is that there is "some" benefit to doing this,but ultimately you're still dealing with a roofless car and the structure was never designed to handle the stresses of our modern hotrodding expectations.anyways.....
the main thing to do is to ensure the car is supported at the suspension load points(simulating the car sitting on 4 wheels) and that all original structure is straight.there are many ways to measure this,but a lazer measuring system(the frame shop will probably have one) is by far,the best way to do it.DO NOT weld anything into the structure until you know the tub is straight and that doors,trunklid,and convertible top open and close properly.
now the frame shop should clamp the car to the frame rack(using the pinchwelds on the rocker panels will usually suffice) and confirm that all moving doors,etc are opening properly.apply a little upward force to the underbody with bottle jacks(floor,torque boxes,and suspension mount points) to see how this affects door gaps.usually at this point you have to make an educated guess to allow for "settling" once the subframe connectors are installed.
mock the connectors up and TACKWELD them in place.now,stop and check the "sag" without the bottle jacks and sill clamps on the car.if you like the fit,keep going........if not,STOP,grind off the tack welds and try again.
in closing,don't be afraid to "overbuild" the connectors with additional gussets and bracing.remember,your car will also twist when driving in the real world so consider the stress points and address them at the same time.
good luck!
leftcoast carl.
 

·
Moderator
Joined
·
5,145 Posts
hi ed.
i own a 63 ragtop AND a frame shop,so i might be able to offer an opinion.
i have done exactly what you've suggested and it did make a noticeable improvement to body flex.
the truth is that there is "some" benefit to doing this,but ultimately you're still dealing with a roofless car and the structure was never designed to handle the stresses of our modern hotrodding expectations.anyways.....
the main thing to do is to ensure the car is supported at the suspension load points(simulating the car sitting on 4 wheels) and that all original structure is straight.there are many ways to measure this,but a lazer measuring system(the frame shop will probably have one) is by far,the best way to do it.DO NOT weld anything into the structure until you know the tub is straight and that doors,trunklid,and convertible top open and close properly.
now the frame shop should clamp the car to the frame rack(using the pinchwelds on the rocker panels will usually suffice) and confirm that all moving doors,etc are opening properly.apply a little upward force to the underbody with bottle jacks(floor,torque boxes,and suspension mount points) to see how this affects door gaps.usually at this point you have to make an educated guess to allow for "settling" once the subframe connectors are installed.
mock the connectors up and TACKWELD them in place.now,stop and check the "sag" without the bottle jacks and sill clamps on the car.if you like the fit,keep going........if not,STOP,grind off the tack welds and try again.
in closing,don't be afraid to "overbuild" the connectors with additional gussets and bracing.remember,your car will also twist when driving in the real world so consider the stress points and address them at the same time.
good luck!
leftcoast carl.

If you use pinchweld clamps, the front is going to sag due to engine/trans weight and the rear will sag due to axle weight.
I would use stands under the suspension as you said at the beginning of your
post. Is there a reason you move it to the rocker clamps?

EdwardsSS, with the tolerance these cars were built with, a laser would not be needed. If you find a shop with one, great. Laser, ultrasonic, and electromechanical computerized systems are accurate and will work great but
a 3 dimensional mechanical measuring system (non computer) will do a great job also. Someone that knows what they are doing can also do it with a tram gauge, flat floor and CAREFUL measurements.
Check the shops in your area and see what is available, post back your options. In our area the few with computerized systems won't work on old cars.
Our computer system has no data for old cars.
 

·
Premium Member
Joined
·
4,612 Posts
If you use pinchweld clamps, the front is going to sag due to engine/trans weight and the rear will sag due to axle weight.
I would use stands under the suspension as you said at the beginning of your
post. Is there a reason you move it to the rocker clamps?

EdwardsSS, with the tolerance these cars were built with, a laser would not be needed. If you find a shop with one, great. Laser, ultrasonic, and electromechanical computerized systems are accurate and will work great but
a 3 dimensional mechanical measuring system (non computer) will do a great job also. Someone that knows what they are doing can also do it with a tram gauge, flat floor and CAREFUL measurements.
Check the shops in your area and see what is available, post back your options. In our area the few with computerized systems won't work on old cars.
Our computer system has no data for old cars.
you've added some valuable points technova.
yes,you are correct that the engine/trans weight will add some sag.i was thinking about when we did my car and the front clip was off,so i wasn't considering the additional weight(1/2 asleep when i posted:rolleyes:).if edward's car has a full front end on it,he will have to support the car at the suspension points.the reason i suggested the sill clamps is because i find it difficult to raise the car enough on the floor to safely get under the vehicle(6'3" 280 lbs:eek:)and still keep it level enough to measure or weld. my frame rack permits me the luxury of being recessed under the centre of the car in a squatting stance to effectively see and work on it.not everyone is equipped this way,but our friend suggested he has a good frame shop nearby and he might have them do the work.
all lazer measuring systems that i'm familiar with do not include older spec's,but can be set up in a "non-spec" mode and can be measured from using a datum line(an imaginary line through the centre of the car).i'm not running down your suggestion on a 3-point measuring system(the lazer is also a 3-point system),but the lazer takes the human error out of the procedure and generally will allow a computer printout for future measuring.if it's not available,then go with the next best thing,but i love the technology and apply it to every job when possible.
leftcoast carl.:)
 

·
Moderator
Joined
·
5,145 Posts
I have done the non-spec measuring with our computer system also, it's time consuming with ours(Car-O-Liner). I am looking at getting Chief laser for the other rack.
I do like the ability to raise the rack up, (I'm 6'5").

EdwardSS, in addition to having the panels straight and the closure panels (hood, doors, trunk lid, top) fit and work properly, ask them about corrosion protection and welding qualifications.
They need to have all areas painted or rustproofed where welding was done. If they weld a boxed section they should be coating it with rustproofing inside afterwards. Any lap joints should have weld thru primer in the joint.

If they are truck frame shop or chassis shop they may not be familiar with the welding requirements for unibody cars. The thinner steels in unibodies are less tolerant of heat. You can't just crank up the 220V MIG and start welding.
If they work on unibody vehicles then ask to get a look at some of their work in progress. Although not a true indication of weld quality, the appearance of their welds means alot. If the welds look bad, go elsewhere.

Of course, also ask about warranty, time frames, customer visits, etc.
A walk around is a good idea when you drop the car off. Go around the car with the shop OWNER and a note pad. Make note of any defects (or lack of defects) in the paint, chrome, interior and area they will be working. This helps later on when there is a scratch in the car and you claim it was not there previously and the shop says it was. It also protects the shop in case you try to get them to pay for something you scratched a few weeks ago.
Have the OWNER sign the notes and keep it, give him/her a copy if possible.
 

·
Premium Member
Joined
·
2,161 Posts
Discussion Starter #10
Thanks guys.

Your suggestions should go a long way. I'm going to print out this post/threads and take it with me. I'll let you know how it turns out.

Have a great weekend,

Ed
 
1 - 10 of 10 Posts
Top