Example VCR External Frame Construction

Web page 3: Example VCR Construction With External Frame

There are advantages to building an "external frame" seperate from the valve cover. These include not having to work inside or fit the frame into the valve cover, no drilling on the valve cover (if you use the factory mounting holes), easier to build a squared up chassis and install the axles square to the chassis with a carpenters square, easier to install adjustable front axle steering, easier to drill the axle holes at the correct desired height and easier to space the wheels where you want them on the front and back axles.

3.1 Typical VCR External Frame Supplies

Typical supplies for building a VCR external frame are pictured. This includes Lowes/Home Depot/hardware store purchases of aluminum right angle stock for 2 frame sides (cut to length for desired frame length), aluminum flat stock (cut 2/3 pieces for desired frame width), counter sink screws & nuts (for drilling & connecting frame rails to frame width flat stock), turnbuckle (for adjustable steering) and 5/16 washers (for spacing as needed). Also required are E-bay/Amazon.com/vendor site purchases of four scooter and/or inline skate wheels plus matching "608" ball bearings. A supply of inline skate spacers is recommendedto assist with spacing wheels on the 5/16 axle rod. Also required is purchase of 5/16 FINE Threaded rod and a supply of matching nuts from Arkansas Welding Supply in Hot Springs (the 5/16 coarse threaded rod sold elsewhere does not work as well with the "608" ball bearings 8mm inner diameter).

Note: Soft aluminum is easier to work with than steel stock and/or stamped steel covers, however, you will still need some combination of electric drill/drill press, file(s)/grinder(s)/sander(s), metal cutoff tool/metal cutting blade(s)/hacksaw, and assorted hand tools, drill bits and countersink bit.

3.2 Typical VCR External Frame Assembly

3.2.1 Top View
Pictured to the left is an example assembled external frame assembly with side frame rails and cross pieces cut to length to match the associated valve cover. Also installed are the 5/16" fine threaded axles cut to desired width for front and back axles (cut threads filed for threading on nuts). Also shown is installed turnbuckle for adjustable front axle steering (elongated axle hole to allow adjustment). Note method of installing cross pieces under horizontal frame rails and using counter sink holes and matching screws and nuts to provide a flat surface for bolting on valve cover.

Typically, you can use valve cover factory holes and drill horizontal frame rails to match mounting. Since the entire VCR weighs less than 10 lbs, you don't necessarily have to use mounting hardware on every factory hole. To avoid potential interference/ground hitting problems when your VCR comes down a launch ramp and transistions to level ground, it is better to have the front axle & wheels positioned forward, but not ahead of the valve cover for the "Stock" class. One of the advantages of the flat surface external chassis is you can position the valve cover where you want it before drilling mounting holes.

3.2.2 Bottom View

Pictured to the left is the example external frame turned over and viewed from the bottom side. Note that it is usually better to have the vertical side rails of the aluminum stock on the outside of the frame. This prototype frame appears to have "extra holes" because of changing the frame to have vertical side rails on the "outside" and moving the front axle forward and relocating the valve cover mounting to correct launch ramp ground transistion interference problems. These types of issues are easier to correct with an external frame than other typical construction methods.

3.3 Typical Valve Cover Installed

The top picture to the left shows the valve cover installed on the example "Stock" class external frame. Note that no drilling was required on the valve cover other than design optional cosmetic items (i.e., roller bar, drivers head, exhaust pipes and front emblem).

Paragraph 3.4: Additional External Frame Example

The bottom picture to the left shows a similiar external frame construction with a longer frame and wheels ahead of the valve cover for the "Modified" class VCR racing. The holes drilled in the chassis (visible & not visible) along with minimizing mounting hardware, were necessary to bring the total VCR weight under 10 lbs.

This also illustrates design construction tradeoffs versus cosmetic design ideas.