How to build a rat rod. #ratrodsa

Building a ratrod

By now you should know what a rat rod looks like and maybe you want to build one. What ever the reason, here you will find some interesting bits and pieces used for or when building your rat rod.

A good place to start is to get the lingo going:

Channeling: By cutting and allowing for the body to sit lower on the frame and closer to the ground, without making any alterations to the suspension.
Sectioning: Sectioning is to remove from the middle of the car, all the way through. Not only the roof.
Chopping: Chopping involves cutting a section from the roof pillars and re-welding them in order to drop the roof. By doing this you have to plan for cutting or making a windshield.
Suicide doors: Changing the position the door hinges opening the doors from opposite ends makes entering and exiting easier.
Suicide front suspension: Traverse leaf spring and solid axle front suspension most often found in early ford models. Suicide suspension are usually mounted all the way to the front of the frame.
Flathead: A type of engine design that houses the valves inside the block next to the sleeves. With the valves in the side position, the section covering the cylinders are flat.
Hemi: In a hemi engine the valves are placed in the head. The part covering the cylinder forms a hemispherical combustion chamber in cylinder head, with the plug in the center.
Rust: The name of the color that rat rods are often covered with.

Things to consider before you start building a rat rod.

  • Basic mechanical knowledge
  • Access to tools and workshop


The Frame
Most guys start building from the ground up, that is a great idea, because turning the car upside down later may not work.

Decide which rod you want to build first, then source it. Online classifieds is the easiest place to start looking. Stripping everything down to the frame usually happens first. With the frame completely removed and all the brackets and mounts removed you can start cutting and changing the frame to suit your look.

Make sure the surface you are building on is level. Safety is a concern. Depending on the condition of your original frame, you may need to add in additional cross members or box up c-sections depending on the load you will be adding.

You can get tubing and piping anywhere, here is a link to a South African steel supplier:

When it comes to building a rat rod there are no rules, as there are no 2 rat rods alike.

Which engine do you like?

The Engine
A good time to decide which engine to use, this is where some mechanical skills comes in handy. Depending on your skills level you can easily buy a running motor and install that or go all the way and re-condition an engine from scratch.

A question often asked is, what is the difference between a big block and a small block v8?

Here’s a few pointers:

  • It has nothing to do with cylinder displacement
  • Big blocks are physically bigger
  • Small blocks have in-line valves and big blocks use cantered valves
  • Big blocks have bigger bores
  • Big blocks were used for heavy work and physically bigger vehicles
  • No one makes big blocks anymore
  • Small blocks have smaller valves
  • Big blocks have better flow characteristics

When you place a big and small block next to each other, you will see the difference clearly.

Inline and transversely mounted engines
When looking at the engine position in relation to the length of the car, you often find two configurations. Inline engines work the easiest.

You can salvage engines anywhere. You might even be surprised to see where they come from once you start shopping around. There are rat rods out there, fitted with tractor and truck engines.

What ever you do, make sure that you can find parts when you need them. The last thing you want to do is get stuck on the other side of Kimberly, needing a part that must be fabricated.

If you choose to re-condition your engine, you need to take the following into consideration:

  • skimming and honing
  • Blueprinting
  • Cylinder re-bore
  • Re-sleeve
  • Valves and seats

If you don’t know engines, I will suggest first doing some homework. On the other hand another way to quickly learn engines, will be to buy the wrong motor and start repairing on weekends.

Moving on! Remember that setting up the engine is the longest most boring part of the build but by far the most important. Get your engine misaligned and you will set off a chain reaction of problems from where your transmission starts to wheel alignment.

No evading the fact that setting the engine in the frame is important.

Suspension Types4

The Suspension
When it comes to suspension, you can go one of two ways. Spend no money on suspension and at the same time start saving for a kidney transplant or make a plan. With suspension, making a plan is easy, you have many ways to set up suspension, front and back.

Rat rod independent - solid axle suspension

Front suspension
Two front suspension types are commonly used. A straight axle parallel spring leaf (old fords) gives a hot rod look when mounted suicide style(cross bracket out up front). Independent suspension performs better than leaf springs but are at the same time more difficult to install.

Rat rod air suspension bagEver seen a rat rod flat on the ground?

That’s airbags. You can add airbags into your suspension, when set-up all the way round controlling the ride height becomes possible. You can get lift up to 24 centimeters, riding on air bags makes for a smoother ride.

Rat rod rear suspension

Rear suspension comes in many different configurations that incorporates either springs or leaf springs. Different rear suspension types include three or four link, triangulated four link, Watt’s or Panhard systems. You can mount any kind of suspension, in most places. Make sure you measure and weld the components into the right place.

Key points when installing the rear suspension to consider are:

  • Placing the pinion angle parallel to the motor and transmission combination.
  • Longer rear bars gives better performance, but you can shorten them.
  • You need a minimum of about 8 centimeter up and down travel.
  • The more you tilt the shocks the less effective they become.
  • Pinion angle +- 3 degrees.
  • Operating angle also +- 3 degrees.

The common problems with rear suspension installs are: axle wrap, wheel hop, binding up or vibrations. Vibrations can have various causes, some are:

  • Bad drive line angles.
  • Bad or worn u-joints.
  • Loose worn mounts.
  • Bad or damaged bearings.
  • Out of balance drive shaft.

Rat rod rolling chassis

The Body
Time to chop, channel and section, depending on how you want your rat rod to look like. Start by mounting the bare stripped body on the rolling chassis. A block and tackle (chain block) is a valuable part when you are working alone.

Rat rod channeling_body

When fitting the body, some cutting may be needed on the front, back and wheel arches, depending on how much shorter you want to make your rat rod. Carefully place the body into place and mount it on the frame, before starting with the chopping or sectioning.

You want to have the body in place and bolted down before any chopping or sectioning happens. Why? Things move when you weld and even cut. To keep the symmetry, add braces that are welded to the body before chopping the roof. This way you can be sure that noting moves.

Rat rod braces for cutting

Mount the body then mark out the section you want to remove with masking tape, then add braces and cut. You can use any off-cuts, scrap steel tubing or round bar lying around as braces.

Rat rod chopping and sectioningAt this point of the build sorting out the seating positions usually happens, remember to get those right, attitude is everything. Other parts typically looked at this time includes:

  • Pedal positioning
  • Window shape and sizes
  • Flooring
  • Steering position
  • Transmission and drive shaft tunnel
  • Gauges and switches
  • Bolted transmission cross member

Rat rod steering

The Steering
When it comes to steering you get two types, the steering box or a rack and pinion, both convert rotational movement from the steering wheel to linear movement.

Steering usually comes in a manual or power steering (assisted) depending on the age of your donor vehicle.

Make sure the steering you will be installing has no play. Play is when the steering wheel have to travel a distance before the wheels respond. Complete steering kits are easily bought from most parts retailers. Mounting the steering box is straight forward and don’t forget to check your driving position before welding it in.

Rat rod headlights

The Lights
At this point your rat rod starts taking shape, and next will be wiring. Inspect the old loom, if you will be using it, make sure to fix the damaged areas. Leave or remove the unused parts… that’s up to you.

The headlights make up a big part of how your car will look and one of the places you often see custom-made light housings. The headlights on the older cars did not work with halogen bulbs like today’s cars, meaning that if the lights stopped working you will have to  convert to halogen bulbs or a sealed light unit.

You can easily apply the fix on a low-budget. Modifications include making adapter plates to fit a sealed light in a reflector bucket. If you have the newer plastic sealed units, you can always cut the fittings and make them fit to almost anything, even the right size stainless bowls from the R1 shop.

A popular design trick is to move the indicators inside the headlights, it looks pretty cool. To spare yourself some headaches, it’s always a good idea to weatherproof the headlight units. To keep water out you can glue thick o-rings together or cut an inner tube to make a seal. Apart from waterproofing, you also need to prevent vibrations.

light plugsConduitStainless steel plumbing conduit works great to protect and hide the electrical wires running to the headlights. There are many nice strong plug fittings and super cheap. All you need is an old computer to salvage. Headlight mounting brackets are made from anything, as long as they are strong enough. Making a rubber gasket underneath the mounts reduces vibrations drastically.

The Petrol Tank
Before you get creative with making and fitting a petrol tank, you have to consider safety. Yes, even when building a rat rod, safety first. Don’t mount the petrol tank where is will cover you with fuel if something goes wrong.

Some odd objects turned into fuel tanks include: geysers, beer kegs, unexploded army missiles, motorcycle tanks and even a 2lt Coke bottle, which probably wont get you to the desert. It is important that the petrol tank is accessible to fill easily.

Seats are usually fabricated bomber style, and made of sheet metal. Mock up panels using cardboard or paper first,  then transfer to steel. Benches are another way if you do not want to use bucket seats.

The Upholstery
You’re building a rat rod and not spending cash is all part of the plan. I’ll say that anything apart from a loose, upside down beer-crates will work. That is already saying too much about upholstery for a rat rod article, at least for this article.

spacer bar

In Conclusion
These cars are built not bought, love getting your hands dirty? If the answer is yes, what will be your next project? Please let us know in the comments bellow.

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