Posts Tagged ‘C4 Corvette hot rod suspension’

Installing the front coil over shocks in the 1929 Ford Hot Rod

Friday, May 21st, 2010
 
Installing the front coil over shocks in the 1929 Ford Hot Rod
 
 The C4 Corvette suspension that I removed form the 1986 Corvette Indy Pace car convertible has found a new home in the 1929 Ford Model A hot rod. Everything is just about complete on the hot rod chassis. My first attempt at designing and developing an upper shock mount for the coil over shocks just did not impress me. I felt the design was too bulky and awkward looking. Simply said, it was not a clean design. I am the sort of person that if I am not pleased with something, especially something I built, I need to fix it or I will always regret it if I don’t. With those thoughts in my mind, I decided to cut the upper coil over shock mounts from the chassis. Of course, this was no easy task. When I put something together, I tend to do it well. With the heavy welds around the entire shock mount, I was grinding for some time. After a few hours, I manage to remove the upper coil over shock mounts and nicely clean up the chassis. Now I was ready for a second attempt at this.
1929 Ford Hot Rod front coil over shock mount - view 1 - this was my first version of the upper coil over shock mount.  A shock from the rear suspension of a Jaguar XJ-12 was used.  It was the correct length and also seems to have the correct spring rate.

1929 Ford Hot Rod front coil over shock mount - view 1 - this was my first version of the upper coil over shock mount. A shock from the rear suspension of a Jaguar XJ-12 was used. It was the correct length and also seems to have the correct spring rate.

 

1929 Ford Hot Rod front coil over shock mount - view 2 - The upper mount just did not have the right look for me so it was removed.

1929 Ford Hot Rod front coil over shock mount - view 2 - The upper mount just did not have the right look for me so it was removed.

 

1929 Ford Hot Rod - Jaguar coil over shock - This shock has about 13.5 inch distance between mounting hole centers and is a perfect size to use on the front suspension of my hot rod.

1929 Ford Hot Rod - Jaguar coil over shock - This shock has about 13.5 inch distance between mounting hole centers and is a perfect size to use on the front suspension of my hot rod.

Originally I had a Jaguar independent rear end that came with four coil over shocks. I sold the rear end and kept the coil over shocks. This was part of the package that came with the 1931 Ford Model A 5 window coupe I previously purchased and sold. I found that these shocks had a perfect distance between the mounting holes and seemed to have the correct spring rate for the front of my 1929 Ford Model A hot rod. My intention is to use these coil over shocks temporally till I generated more funds for some nice chrome or aluminum coil over shocks.

1929 Ford Hot Rod - front lower coil over shock mount - version 1 - this is one possible mount that I am thinking of using, but still not sure.

1929 Ford Hot Rod - front lower coil over shock mount - version 1 - this is one possible mount that I am thinking of using, but still not sure.

 

1929 Ford Hot Rod - front lower coil over shock mount - version 2 - this another mount up for consideration and is the same as the lower mount I used on the rear shocks of my hot rod.  I am leaning towards this style, but made out of stainless steel instead.  Eventually, I intend to polish all of the aluminum suspension parts, have chrome coil over shocks, so this style of mount using stainless steel makes a bit of sense.

1929 Ford Hot Rod - front lower coil over shock mount - version 2 - this another mount up for consideration and is the same as the lower mount I used on the rear shocks of my hot rod. I am leaning towards this style, but made out of stainless steel instead. Eventually, I intend to polish all of the aluminum suspension parts, have chrome coil over shocks, so this style of mount using stainless steel makes a bit of sense.

 

The lower shock mount is basic. I used a triangle pattern for the base of the shock mount. A couple of half moon shaped brackets were welded to the base of the lower shock mount. All of these pieces where fabricated from 0.25 inch steel plate and cut out on my metal cutting band saw. To make sure for a perfect fit, I bolted the half moon brackets to the shock, and then positioned the shock with brackets onto the lower shock mount base. This was then tack welded in place. Once I was happy with the position and fit of the shock, the half moon brackets were permanently welded in place. This assembly fits perfectly into the lower control arm from the C4 Corvette. Another consideration for the lower shock mount is to fabricate one from 2 inch stainless stain square tubing and using small spacers inside to make up the difference between the width of the shock mount and the opening of the bracket. I am leaning more towards this style considering that I will eventually polish all of the aluminum suspension parts and use chrome coil over shocks.

1929 Ford Hot Rod front coil over shock mount - view 3 - I discovered that if I angled the shock in more towards the frame and directly under the upper control arm that my spring rate was not effected by much.

1929 Ford Hot Rod front coil over shock mount - view 3 - I discovered that if I angled the shock in more towards the frame and directly under the upper control arm that my spring rate was not effected by much.

 

1929 Ford Hot Rod front coil over shock mount - view 4 - A set of new upper shock mounts were made from 0.25 inch plate steel.  A always a template was created just in case I ever wanted to make more of these brackets.

1929 Ford Hot Rod front coil over shock mount - view 4 - A set of new upper shock mounts were made from 0.25 inch plate steel. A always a template was created just in case I ever wanted to make more of these brackets.

With the lower shock mount placed onto the lower control arm, I started to examine various mounting options for the upper shock mount. Very quickly I realized that I could create a much smaller mount just under the mounting bar of the upper control arm from the C4 Corvette. The only concern I had was that the angle of the shock was increasing slightly. The correction factor when mounting shocks on a 15 degree angle is 0.93 and for a 20 degree mounting angle is 0.88. This is approximately the change I wanted to introduce to the suspension. So to check things out, I was able to set the upper shock mount temporarily. I added a few sand bags as extra weight or ballast to compensate for parts still not on the chassis. Then I positioned my 250 pounds onto the chassis. I took a resting position measurement and another one when I started to bounce up and down on the chassis. This activity resulted in only a 1 inch movement in the suspension at the best of times. This seems reasonable to me so I then decided to create a second version of the upper shock mount. Once again to ensure a perfect fit, I bolted the newly fabricated upper shock mounts to the shocks. The complete coil over shock assembly was then fitted to the chassis. With everything in place, the upper shock mounts were tack welded to the chassis. Making sure that this was what I wanted this time and that the mounting positions were correct, I removed the upper control arm and shock for the final welding process of the upper mount.

1929 Ford Hot Rod front coil over shock mount - view 5 - The new brackets were bolted to the upper mount of the coil over shock.  With everything in place, the new mounts were tack welded to the frame.

1929 Ford Hot Rod front coil over shock mount - view 5 - The new brackets were bolted to the upper mount of the coil over shock. With everything in place, the new mounts were tack welded to the frame.

 

1929 Ford Hot Rod front coil over shock mount - view 6 - Everything looked as it should, my spring rate was not reduced my much with the increased angle of the coil over shock.

1929 Ford Hot Rod front coil over shock mount - view 6 - Everything looked as it should, my spring rate was not reduced my much with the increased angle of the coil over shock.

 

1929 Ford Hot Rod front coil over shock mount - view 7 - This new upper mount looks much better then my original version.

1929 Ford Hot Rod front coil over shock mount - view 7 - This new upper mount looks much better then my original version.

 

1929 Ford Hot Rod front coil over shock mount - view 8 - This is the finished and primed result of my efforts.  I think this doesn't look too bad.

1929 Ford Hot Rod front coil over shock mount - view 8 - This is the finished and primed result of my efforts. I think this doesn't look too bad.

 

1929 Ford Hot Rod front coil over shock mount - view 9 - The front suspension is painted for now and mounted back onto the frame.  Later on I intend to purchase a nice set of polished coil over shocks to replace the 1 inch square tube.

1929 Ford Hot Rod front coil over shock mount - view 9 - The front suspension is painted for now and mounted back onto the frame. Later on I intend to purchase a nice set of polished coil over shocks to replace the 1 inch square tube.

Standing back and looking at the new version of the upper shock mount, I felt the entire process was well worth the time and effort. In my mind the design was much cleaner looking. This outcome is in line with my over all goal with this project. It is to build a good looking, safe, and, have great handling characteristics hot rod with a minimum of expense. So far, I am right on track.

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Chassis / Frame Design for the 1928 to 31 Model “A” Ford Street Rod – Part 4

Saturday, December 19th, 2009

Chassis / Frame Design for the 1928 to 31 Model “A” Ford Street Rod – Part 4 

With the new steel at home in the shop it was time to formulate a plan for the construction of my new chassis.  I thought that I would start out easy and duplicate the shape of the front frame rails.  Using the original 1928 – 31 Ford Model A frame / chassis, I traced the pattern of the front frame horns onto a piece of scrap ¼” plexi-glass. This template was almost 3 feet long.  At the time, I felt it would be a good idea to have templates for every bracket and shape I designed for the chassis.  This will save me time if I would like to build another car using the same suspension concept.  The pattern was then cut out on a stationary scroll saw I have in the shop.  Having acquired a full wood shop over the years has a few advantages or benefits towards the build process of my street rod. 

 

1928 - 31 Model A Ford front frame / chassis template pattern to transfer to the 2" x 4" rectangular steel tubing

1928 - 31 Model A Ford front frame / chassis template pattern to transfer to the 2" x 4" rectangular steel tubing

The template duplicating the front end of the original 1928 – 31 Ford Model A frame / chassis was then placed onto the end of each long section of the 2” x 4” rectangular tubing tracing out the pattern.  At the time I did not have my plasma cutter and I needed to figure out how to cut this shape out with some level of accuracy.  Using my angle grinder equipped with a very thin cut off wheel, I very carefully cut the shape out on the sides of the rectangular tubing.  This took a bit of time, but I had no other options for this task.  I used the cut off wheel to slowly score through the steel tubing with a final desired shape of the frame rail.  Once this was completed, I boxed in the openings on the top and bottom of the frame rails with 1/8” steel plate.  In the end, the finished corners edges had the same rounded contour shape as the original 2” x 4” steel rectangular tubing.

C4 Corvette rear suspension veiw # 1 for the 1928 - 31 Model A Ford frame / chassis.  This is showing the riser or kick up of the frame rear section.  A 4" kick up was perfect for my appliction.  The rounded edge of the tubing allowed for a very heavy and deep weld that was ground even with the side edge of the frame for a very clean and even look.

C4 Corvette rear suspension veiw # 1 for the 1928 - 31 Model A Ford frame / chassis. This is showing the riser or kick up of the frame rear section. A 4" kick up was perfect for my appliction. The rounded edge of the tubing allowed for a very heavy and deep weld that was ground even with the side edge of the frame for a very clean and even look.

It then came time to set up the two frame rails on the shop floor using axle stands and small blocks of wood for shims.  Both frame rails were levelled off using the laser level and balancing the diagonal corner measurements.  To help with this, I drilled small 1/8” holes in the center of the rectangular tubing at each end of the frame rails.  This became a constant point of reference to make sure everything was level and square.  Once this was completed, I used some scrap angle iron and welded several pieces across the width of the frame to keep everything in place.  My two most important measurements were the width of the frame along the centre line of the front axle and the width of the rear differential carrier mounts.

 

C4 Corvette rear suspension veiw # 2 for the 1928 - 31 Model A Ford frame / chassis.  This is the initial view of the rear of the frame.  I ended up making it slightly too long and later shorter the length of the frame so it.  This change will allow the 1931 Ford coupe body to fit nicely over the frame / chassis rails.

C4 Corvette rear suspension veiw # 2 for the 1928 - 31 Model A Ford frame / chassis. This is the initial view of the rear of the frame. I ended up making it slightly too long and later shorter the length of the frame so it. This change will allow the 1931 Ford coupe body to fit nicely over the frame / chassis rails.

The outside frame width at the center line point for the front axle center will be slightly wider than the stock 1928 – 31 Ford Model A frame / chassis.  The width will be the same as taken from the original C4 Corvette front cross member.  An important point to keep in mind, the design for the C4 Corvette suspension must not change.  Any changes to the suspension design will result in poor handling performance on the street rod or possible disastrous and dangerous operating conditions for the street rod and occupants.  You do not want to be on the 6 o’clock new cast. 

C4 Corvette rear suspension veiw # 3 for the 1928 - 31 Model A Ford frame / chassis.  This view show the mounting for the C4 Covette stablizer rods or "dog bones".  I used 4" square steel tubing cut to the shape in the picture.  One side of the tube was cut off to make the tube into a channel.  This give me the proper width for the stabilizer or control rods.  The open end of the tube was welded to the side of the frame.  A piece of 2" square tubing was used to created the final mounting bracket for the stabilizer rods.  I used a metal cutting band saw for all of the metal cutting here.

C4 Corvette rear suspension veiw # 3 for the 1928 - 31 Model A Ford frame / chassis. This view show the mounting for the C4 Covette stablizer rods or "dog bones". I used 4" square steel tubing cut to the shape in the picture. One side of the tube was cut off to make the tube into a channel. This give me the proper width for the stabilizer or control rods. The open end of the tube was welded to the side of the frame. A piece of 2" square tubing was used to created the final mounting bracket for the stabilizer rods. I used a metal cutting band saw for all of the metal cutting here.

After measuring the mounting distance for the C4 Corvette (1986 Corvette convertible) rear differential carrier, I decided on another deviation from the original 1928 – 31 Ford Model A chassis / frame.  The new mounting brackets for the differential carrier will be welded to the outside section of the frame rails.  I designed tear drop brackets and cut them out using 5/16” plate steel.  These brackets required a small notch to be removed from the body frame rails.  I also remove the rear floor panels and one of the rear cross braces on the body.  This will allow the 1931 Ford Model A coupe body to be easily mounted to the new chassis with the new chassis just fitting in between the body rails of the coupe body.  I will explain more on this later, in another section,  on how to strengthen the rear of the body to compensate this modification.  Using this type of chassis design, will not allow the use of a rumble seat.  Again, to make design process easier, I removed all floor and trunk panels on the 1931 Ford Model A coupe body.

 

C4 Corvette rear suspension veiw # 4 for the 1928 - 31 Model A Ford frame / chassis.  This view shows a cross member tacked in place.  It will provide a mounting location for the center differential carrier housing and add much needed strenght to the 4" kick up on the frame.  It will act as a gusset for the kick up.

C4 Corvette rear suspension veiw # 4 for the 1928 - 31 Model A Ford frame / chassis. This view shows a cross member tacked in place. It will provide a mounting location for the center differential carrier housing and add much needed strenght to the 4" kick up on the frame. It will act as a gusset for the kick up.

A few more measurements on the length of the chassis frame rails needed to be made.  I discovered that the rear of my new chassis was slightly too long.  The body would not drop over chassis frame rails.  The chassis was hitting the rear of the body frame.   I quickly shortened that rear of my new chassis making it just long enough to keep the frame nicely within the 1931 Ford coupes body  frame rails.

C4 Corvette rear suspension veiw # 5 for the 1928 - 31 Model A Ford frame / chassis.  This shows the tear drop brackets I made for mounting the C4 Corvette rear suspension unit to the frame.  I perfer heavy and very deep welds and then grind  them smooth for a very finished look.
C4 Corvette rear suspension veiw # 5 for the 1928 – 31 Model A Ford frame / chassis. This shows the tear drop brackets I made for mounting the C4 Corvette rear suspension unit to the frame. I perfer heavy and very deep welds and then grind them smooth for a very finished look.

 

C4 Corvettes (1986 Corvette convertible) use an aluminum support beam that is fastened to the rear of the transmission and the front of the differential.  This would not look too good on a street rod.  Instead, I decided that two new cross members would be used on the chassis.  One cross member for the transmission and another cross member for the differential.  These two cross members would also increase the strength of the new chassis.  I used 2” x 3” rectangular steel tubing for these cross members.  I tack welded the cross member in place for the differential.  The addition of this cross member to the rear of the chassis will also form as a gusset to help strengthen the welds for the rear kick up.  The angles of the transmission and differential carrier are very important.  Both the transmission and differential cannot be mounted straight.  The transmission must be angled downward 3 degrees from horizontal and the pinion on the differential must angled upwards 3 degrees from horizontal.  This will avoid driveline vibration and help preserve your universal joints on the driveshaft.  I will include a section later on with more details on setting up the driveshaft, transmission, and differential.

The next step was to mount the upper and lower control arms to the side of the new chassis.  Now I had a bit of a problem.  The chassis was to narrow.  How would I make the chassis wider to allow the mounting of the rear control arms?  I did not want to use the original mounting brackets.  They were just too ugly and I did not have anything to attach them to.  After a bit of thought, I decided that if I used 4” square steel tubing with one side cut off, that I could mount the rear control arms tastefully to the side of the chassis.  A new set of control arm mounts were designed and constructed from 2” square tubing with the ends rounded and one side cut off.  These mounts will be welded to the 4” square tubing that was already tacked to the side of the frame rails.  Again I matched up the angle for the control arm mounts to the same angle found on the 1986 Corvette convertible donor car.

Please note:  I will be including complete measured drawings and templates for the various sections of this 1928 – 31 Model A Ford Hot Rod frame / chassis to purchase in the very near future. 

Come back next week to see how I created and started the design for adapting the C4 Corvette (1986 Corvette convertible) front suspension to the new 1928 – 31 Ford Model A chassis / frame.

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