Posts Tagged ‘1931 ford’

Chassis / Frame Design for the 1928 to 31 Model “A” Ford Street Rod – Part 3

Sunday, December 13th, 2009
Chassis / Frame Design for the 1928 to 31 Model “A” Ford Street Rod – Part 3
 Before any suspension is removed from the Corvette, it is a very good idea to record how everything is mounted to the car.  Now with digital cameras, I always take pictures of any demolition, modification, or repair for future reference.  In the case of the Corvette suspension, I recorded on paper the dimensions, angles, and location of all parts mounted to the frame of the car.  I did not have a digital camera then.  You might think you will remember every detail, but I can guarantee that you will forget something important.  It is said that a picture or detailed sketch is worth a thousand words.  I believe this from years of experience.

The first step was to remove the motor and transmission from the car.  Now the front suspension can be removed very easily.  No cutting tools are required for the removal. The front cross member is bolted to the main Corvette frame.  The cross member also has the mounting for the motor mounts.  This is so well designed, that all of the front suspension components are attached to the front cross member with the exception of the upper shock mounts.  I will come out of the car as a complete unit.

It is important not to discard any items from the Corvette.  Every single part removed can be sold.  This is what I did.  I listed many parts on eBay and sold many items locally.  This eventually paid for the car and made me even more money.  I managed to pay for the engine hoist, engine stand, and a new Millar Mig welding machine from the proceeds of this car.  I even put some money in the bank for my next street rod part purchases.  Don’t forget, I still have the Corvette suspension, engine, transmission, and many other parts needed to build my street rod.  I never thought building a street rod was so profitable. 

Next I removed the rear suspension.  Again, everything came out without any difficulty.  Make sure you keep the bolts.  The bolts are all hardened bolts and might be required to mount the suspension in the new Model “A” chassis.  I even removed all of the emergency brake cables, and aluminum brake line splitters.

The front and back sway bars and mounts should to be removed and stored.  One of my main goals in the design of the new Model “A” Ford chassis was to use as many Corvette parts as possible in my street rod.  This makes the long term maintenance of your street rod very simple.  Corvette parts will always be available whereas custom made parts will be hard to replace when items break or wear out.  Some of the custom parts built today might not be available in the future depending who originally made them. 

C4 Corvette suspension as removed from the 1986 Corvette Indy Pace car convertible.

C4 Corvette suspension as removed from the 1986 Corvette Indy Pace car convertible.

I placed the front and back suspension units on a skid and wheeled them off to my shop.  Now I needed to decide on the details of the chassis design.  I felt that for my first street rod, I would not be too radical in my design.  In some sense, I did select something out of the ordinary by using C4 Corvette suspension on a 1931 Ford Coupe.  This will complicate the design enough and slow down the building process when compared to using traditional parts in a street rod. 

C4 Corvette rear suspension as removed from the 1986 Corvette Indy Pace car convertible.  As few parts need to be replaced due to the accident the car was in.

C4 Corvette rear suspension as removed from the 1986 Corvette Indy Pace car convertible. As few parts need to be replaced due to the accident the car was in.

 I decided to use the same wheel base of 103 ½” as the original Model “A” Ford for a 1928 to 1931 frame.  The mounting of the rear suspension required a narrower frame width.  It was like the C4 Corvette design engineers considered the Model “A” Ford in their original design applications.  The width of the rear frame rails would be narrow enough to fit between the rear body frame rails.  I would only need to make a slight modification to the body frame rails to facilitate the new suspension and chassis.

C4 Corvette front suspension as removed from the 1986 Corvette Indy Pace car convertible.  Everything will be removed from the front crossmember.  I will use the front crossmember for the basis of my design and measure everything on it.

C4 Corvette front suspension as removed from the 1986 Corvette Indy Pace car convertible. Everything will be removed from the front crossmember. I will use the front crossmember for the basis of my design and measure everything on it.

 

 I measured the mounting distance between the upper control arms on the Corvette cross member.  It was slightly wider than the original Model “A” Ford frame.  It is important not to change any part of the original design of the suspension of the Corvette.  Any changes will affect the eventual performance in handling and ride of the street rod.  In some street rod applications, the entire Corvette front cross member can be used as is.  It is not possible for the Model “A” Ford.  I suppose some car builders would say sure no problem, use it as is.  I feel the front of the car would look very ugly and be poorly designed and this option was not for me.  It would be similar to builder using an original Mustang II suspension with the large coil springs.  In a small car like a Model “A” Ford, this will not look good.   Again maybe in larger street rods with the front ends closed in more would this be okay.

C4 Corvette front cross member stripped down and ready to have measurements taken from.  The new street rod cross member will not look anything like this.

C4 Corvette front cross member stripped down and ready to have measurements taken from. The new street rod cross member will not look anything like this.

 Now I had a basic design concept for the new chassis in place.  The original wheel base would be adequate, and a new width at the center lines of the front and rear suspension was determined.  Now, I needed to buy the steel for the new chassis.

Fortunately, in our town, we have a steel supplier.  I purchased 2” x 4”, 0.1” wall thickness rectangular tubing.  Before my purchase, I completed rough sketch of the new Model “A” Ford chassis.  From my sketch, I calculated how much material was required for the main frame rails, rear of the frame, and the new front cross member.   At the steel supplier, I had them cut two sections of the same length of tubing for my new chassis.  We loaded this into my trailer and headed back home to my shop.

The next phase of the project is to complete a mock up of the new chassis with everything only tack welded.

More to come soon, including pictures of the design process.  Make sure you book mark this site and come back for weekly updates.

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The 1931 Ford Model “A” 5 window coupe

Tuesday, December 1st, 2009

The 1931 Ford Model “A” 5 window coupe

After spending a considerable amount of time selling off the 1930 Plymouth parts I did not need on eBay, I started working on the old Plymouth.  Planning out the hot rod was interesting.  I bought a 350 cubic inch GM truck engine and automatic transmission for $500 from a friend.  Another friend from the car club I belong to was tearing down a 1988 Lincoln LSC for his hot rod.  He gave me the rear end, the front spindles, and the aluminum rims with tires.  The front spindles and rear end both had disc brakes, something I thought to be necessary in a modern street rod.  The rotors and pads all were relatively new and was an added bonus.  I even started buying a few bits and pieces of eBay for the build.  Things are starting to shape up. 

The internet is a good resource.  I found many hot rod builds similar to what I was planning.  I also continued signing out books from the library.  Magazines started coming home by the cart load.  I spent a considerable amount of time reading and learning anything I could about building a hot rod.  During the summer time, I attended many cruises and swap meets.  I started to asked lots of questions to builders of hot rods.

The Lincoln rear end was a perfect match for the 1930 Plymouth.  It was the right width for the car.  I started to come up with a plan to adapt the Lincoln front rotors and discs brakes to the stock the 1930 Plymouth front spindles.  It looked like all I needed to do was source out new bearings with the correct sizes or make collars for the spindles to match up to the existing Lincoln bearing in the rotors.  This seemed just too easy.

The frame on the 1930 Plymouth is very sturdy and did not need any extra re-enforcing.  It could easily handle a modern V8 engine.  In my opinion, I would say that the 1930 Plymouth was built very well and much better then Fords in the same time period.  I am a bit puzzled why Fords became more popular in the 30’s since to me, the Chryslers’, and Plymouths, were built so much better.  I guess it was all in the marketing game, even then.

I did a compression test and leak down test on the V8 engine I purchased from my friend.  The results were a bit disappointing.  The tests pointed to several leaky values and rings.  I took the engine apart.  It was even more disappointing.  This engine looked like a coal mine inside.  This happens to engines when the oil is not changed.  I started to plan a rebuild for the engine.  An expense I was not counting on.  Here is a bit of a lesson.  Do not buy an engine you cannot hear running.  

 

1931 Ford 5 window coupe

1931 Ford 5 window coupe

The friend that sold me the engine and transmission also had a 1931 Ford 5 window coupe.  After a bit of time, we came to a bit of an agreement.  I was now the proud owner of the coupe.  It came with a vintage Model “A” frame, a nice Ford flathead V8 engine, and matching 3 speed transmission along with a Jaguar independent rear end.  The 5 window coupe was more in the lines of what I wanted to build.  As it happens, the same friend wanted the 1930 Plymouth so we traded.  Now things are starting to shape up for me.  I have a 1931 Ford 5 window coupe and I was getting very excited about the build.  My life long dream was starting to take shape.

In a few days, I will start talking about the donor car for suspension, drive train, and etc…. along with my reasons for making this selection.  This will be the beginning of the frame / chassis design for the Model “A” Ford.

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