Body Fitting 101

[KGB911]

I received the following PM the other day and thought I would respond to this Great question in a new thread so everyone can benefit. I have also enclosed DC#4 & DC#2 for those of you new to the forum so you will know what this is all about.

Hi Dan,

Had a real hoot a couple of weeks ago with a ride in Tom Veale's 33.

I have read "Dangerous Curves" several times and learn more each time. I am hung up on DC #4 where you advise to level the car on the ground on the tires. It seem you then be inducing "tilt" with the suspension as necessary to make up for any non-level ground.
Why would we not put the frame on stands and shim or adjust the frame to level "in space"
I know I am probably missing something simple but I don't see it.

Thanks
Dick Sipp

To clear things up the word Level is not referenced in my instructions and it is not because none of us truly have a Level surface to work with! The key words are Center line and Datum line that are referenced in DC#2. When using Plumb bobs you will need to level the chassis in the direction you are plotting but of course that has nothing to do with your garage floor or level ground.
We all thought that with this Solid Works computer generated chassis the FF33 would be both rigid and straight! Well the fact is! It is far from Straight or Rigid! On paper and per the mathematical formula’s it should have been but due to the selection of materials and the welding processes it fails to meet the mark. This kit could be assembled by an Orangutan if everything was perfect but it is not, so what I am trying to relate is that compromise will be the Key word throughout the build and trying to make it perfect will only cause frustration.
In answering Dick’s last sentence I stress the following! DO NOT USE JACKSTANDS ON THE CHASSIS. Here is he reason! The chassis will distort differently when supported in locations other than the locations used when finished and going down the road and if you support it with jackstands on the chassis and fit your panels when you put it on the ground rolling your gaps will be way off and you will wonder what happened! When it comes to building this kit most people will find the hardest part of the build to be the panal fitting and IMHO that is all created by? Another post!
Dr. Ruth




DC#4
Plumbing
Isn’t strange how one word could have different meanings!
Assuming the body was attached inline at the factory would be a poor assumption, they simply screw the body to the chassis for shipping purposes which makes things a little confusing from the start. As discussed in earlier posts the body is by no means perfect and therefore compromise is the key word in fitting the body and its parts, ie, hood and grill etc.
I recommend using a wax pencil and going around the body at key points and measuring and marking for reference points to be used to achieve a true center. I suggest scribing a line on the top of the cowl, the package tray and rear valance. I also recommend that you do the same on the chassis at the rear, the center x by the trans tailshaft and the front steering bulkhead and the very front of the chassis. You will find that these points will be used frequently through the build and will be used to center your engine and trans, your gauges, your fuel tank and even the rearend and last but not least your Cupholders!. At this point it is important to level the car “side to side” with your coilover spring adjusters and or air pressure and make sure and have the car on its wheels or at least supported from the suspension pick up points, DO NOT USE JACKSTANDS ON THE CHASSIS.
Place a long straight length of 1 ½” square tubing or suitable material down the center of the car and clamp it in place and hang Plumb Bobs at points you wish to reference like the front and rear bulkheads. Now it’s time to adjust the body to get all the points inline, a ¼” forward or backward on one side or the other will move the centerline at the ends easily 1”. Time spent doing this simple task will pay off many times during your build! Depending on your particular body and chassis you may need to shim or grind some of the firewall to chassis to body mating surfaces to get everything square.
Take your time and do it RIGHT!
Dr.Ruth


DC#2
Self Centered

I received ThunderRod in the Go Kart stage with the body attached with the zip screws placed at the factory. After spending sometime tramming the body and chassis it became apparent that the body would require relocating to get everything to align properly. The chassis is for the most part square with the exception of a few brackets that are welded on with little attention to detail which I will address later. It is very important to create a center-line down the middle and also a datum line down the sides so as to get all the body parts to line up and fit within tolerance. When you start measuring the panals you will find that the measurements are fit for a ruff frame carpenter when finish carpenter specs would have been more appropriate. I have found that with a little patience you can fudge most of the panals to work without excessive modification. That being said, there are panals that are undercut and required compromise. I found this particular body to be diamond a bit and I was forced to move it forward on the pass side so as to get the body to run square with the chassis. If you get the body squared the hood and deck lid will fit with ease and take less time to install, so spending a little time there will pay off in the end.
Dan Ruth

[Buck70]

Originally Posted by KGB911

I received the following PM the other day and thought I would respond to this Great question in a new thread so everyone can benefit. I have also enclosed DC#4 & DC#2 for those of you new to the forum so you will know what this is all about.

I found this particular body to be diamond a bit and I was forced to move it forward on the pass side so as to get the body to run square with the chassis.
Dan Ruth

Dan
I found that the (firewall) was pushing the pass side of the body back quite a bit. When I shimmed the firewall away from the frame on that side it let the body come back forward. I wonder if that twist is what made some need a spacer behind one back wheel to make the tires meet the body lines?

I have also stretched the wheelbase an inch to match the rear fenders better. The new frame tabs were kind of a PITA but it will let me get a better ride height while keeping the anti-squat ratio right. I had sway bar tabs put on the new longer LCA's so a Mustang bar will bolt right on. I need to go read the whole DC series again, where do I find that ?
Dale

[KGB911]

Dale: It is quite unfortunate that any of this must be done to make this kit meet our expectations but that being said I am sure many builders just throw the kit together and have Lot's of Fun!
The Dangerous Curves Ahead thread should be on the front page or not far back at this time.
Dr. Ruth

[tweeker]

It is quite unfortunate that any of this must be done to make this kit meet our expectations but that being said I am sure many builders just throw the kit together and have Lot's of Fun!

I've said this many times.

[tweeker]

I have also stretched the wheelbase an inch to match the rear fenders better. The new frame tabs were kind of a PITA but it will let me get a better ride height while keeping the anti-squat ratio right. I had sway bar tabs put on the new longer LCA's so a Mustang bar will bolt right on. I need to go read the whole DC series again, where do I find that ?
Dale

What all was involved in your wheel base stretch?

[Buck70]

Originally Posted by tweeker

What all was involved in your wheel base stretch?

Rather than thread jack the DR with a long reply I started a new thread called stretched and jacked where I detailed my approach.
DB

[joejohnson50]

X3. This is certainly one of the biggest factors (cost to remediate bodywork) that has me deliberating between the FFR 33 build and other options.

tweeker; "I've said this many times."

KGB911; ..."It is quite unfortunate that any of this must be done to make this kit meet our expectations but that being said I am sure many builders just throw the kit together and have Lot's of Fun!..."

[bapa10]

Originally Posted by Buck70

Dan
I found that the (firewall) was pushing the pass side of the body back quite a bit. When I shimmed the firewall away from the frame on that side it let the body come back forward. I wonder if that twist is what made some need a spacer behind one back wheel to make the tires meet the body lines?

Dale

Dale,

Did you shim the firewall panel or the footbox panel (or both) away from the frame on the passenger side? I'm finding that both footbox panels would need to be shimmed ~3/16 inch away from the frame where the bottoms of the panels meet the body. Would prefer to keep the firewall and footbox panels in the same plane. Also, my passenger side body is flush with the body mount up front. Another constraint. Appreciate your thoughts.

Bill
#420

[Buck70]

Originally Posted by bapa10

Dale,

Did you shim the firewall panel or the footbox panel (or both) away from the frame on the passenger side? I'm finding that both footbox panels would need to be shimmed ~3/16 inch away from the frame where the bottoms of the panels meet the body. Would prefer to keep the firewall and footbox panels in the same plane. Also, my passenger side body is flush with the body mount up front. Another constraint. Appreciate your thoughts.

Bill
#420

Bill I found the footbox panel to be most of the problem but I also slightly trimmed the bottom/back edge of the door latch tabs mostly to prevent abrasion there. This let the body move forward so the extensions fit around the pass front frame tab where it wouldn't fit before. I have heard others moved that tab but mine was OK after the pass side body came forward. I hope that will also help the hood fit better when the whole body comes forward on the pass side.
I have not had all of my panels on at once so I can't say my approach has been fully proven YRMV
Dale

[bapa10]

Thanks, Dale.

Trying to be sure I have body alignment correct before mounting firewall and foot boxes. Have read Dangerous Curves and other threads looking for insight on dealing with foot box to body interference below the firewall. My firewall is trimmed and aligns ok with the body. The body is too far forward where it meets the foot boxes below the firewall on both sides by about 3/16 inch at the bottom (thickness of the fiberglass) and about 1/16 inch at the top. The body is sitting on the door frame rails with about 1/16 inch of the bottom rails exposed at the back and is flush (no exposure) in front below the foot boxes. Both body extensions to the front clear the angle brackets.

The interference with the foot boxes clears if the back of the body is raised, i.e., shimmed ~3/4 inch at the back of the door frame rail at the expense of exposing ~3/4 inch of the bottom frame at the back - not preferred. The passenger side body extension then slightly interferes with the angle bracket on the frame and would have to be trimmed (or the bracket modified). I'd prefer not to shim the foot boxes away from the frame, but the only other choice appears to be to virtually remove the two mating surfaces to the foot boxes on the body. I haven't read that anyone else has had to go that far. Am I missing something? Maybe this is "normal" and the challenge is simply to find the best overall compromise of trimming panels and body. Appreciate any insights or suggestions. Thanks, guys.

Bill
#420

[jmann]

My two cents worth...
Its all compromise. When I was researching the car I had a discussion about the fitting issues with a retired plant manager from one of the big three. He said that commercial cars have similar issues, just look at all the slotted holes. I had to file the body a little where it goes behind the foor panel and some on the panels where they contact the frame, but not much and everything seemed to line up. I centered religiously and set the door bases on the frame. I got the critical dimension from dash to rear of cockpit within 1/8" first time. Everything is acceptably level, which as Dan has said depends on how the car is sitting. Had no issues mounting the doors ( 8 hrs to do both) they line up well on the outside, some work will be required on the inside. Considering the size of the body piece, it fit better than I expected. My experience with original '40's sheet metal was much worse. I do admit that I am building a driving car, not a show car.