Welcome to my Cobra Replica build blog.
Please contact me if you would like to know more detail as i progress."CR3514@live.com.au"

Sunday, June 22, 2014

Tail Shaft Part 1.

In a previous post, I detailed the changes to the diff tail shaft flange on the Holden VE Commodore diff to accommodate a Ford BA style flange and tail shaft universal coupling.
I've been avoiding the day I would have to cut the spigot shaft off the front of the pinion shaft to fit the Ford universal joint coupling.
What's more, there was a lot of effort in finding the Ford part as it is out of production, usually only available from wreckers with a diff still attached.
While researching ways to direct couple the tail shaft to the gearbox, a Tremec TR6060 with the Tri-Flange mount, I found Sonnax in the US make a part sold through The Drive Shaft Shop. Sonnax part number TL35-ALFY-01 to fit the Camaro and G8 models also fitted with TR6060 gearboxes.
After email correspondence to confirm the fit, I purchased one.

Sonnax part number TL35-ALFY-01
fitted to TR6060 gearbox.
After confirming this part, I broadcasted the find to other CR builders I'm in contact with.
One of my friends also bought one and during his fit up discovered that it was also a perfect fit for the original VE Diff flange, which if didn't interfere with the handbrake cable bracket on the chassis, would eliminate the need for the Ford flange conversion and the removal of the spigot shaft on the pinion.

The flange confirmed fit on the original diff Tri-Flange, but interferes with the Hand Brake Cable Bracket welded on the chassis.

Another shot showing the interference.

After measuring up the available cable space, I made a bracket narrowing the distance between the cables, and moving the bracket a few millimetres to create about 10mm clearance to the flange.

Quicker than saying
"Lets Think About This For A Moment"
I cut it off and located the new Hand Brake Bracket.

Bolted in place after confirming location.

Now with plenty of clearance I have ordered another flange, ended up with a standard diff set up with out modifications, standardized the flanges and universal joints to 1350 type bearings.

Next step is to get a sliding tail shaft made up and balanced to fit between the 2 flanges with enough compression to be able to remove down through the chassis if needed.

Power Steering Pump Mount

I eventually relented on the woes of getting a factory Power Steering Pump to sit where I wanted to mount it when I discovered a pic on the web of a CT525 engine from Circle Track with a belt layout exactly as I wanted it.
After looking around there site, with no indication to what was fitted to the engine, I came across a customers car on an LS forum with decent res pictures and zooming in revealed the name and part numbers on the pulley.
An email to them soon had a list of brackets, pump and pulley part numbers to suit the LS3 Corvette belt line.

The bracket mounted to the head.
part number # 71410040

Installed with a new Gates Micro -V 6PK2020 Belt.
Part number #  K060795.

Power Steering PUMP is KRC #63200000
Pulley is 6.5" KRC # 20020650,
They also do a smaller 6" pulley # 2002600

Wednesday, June 18, 2014

Throttle Cable Bracket

With the dual quad EFI, I wont be using the drive by wire (DBW) solonoid or ECU throttle controls.
I have designed a way to use the DBW, but for engineering approval purposes, its easier to do the cable operation at this time.
After measuring up some commercially available cable brackets, I found a few issues, firstly, they dont line up with the throttle leverage cranks on the throttle body and also interfere with the fuel rail mounts, secondly, the cruise control bracket for holley 4150 carbs doesnt fit the EFI quad cranks.

The quads come with a 1/8" steel insulator that goes between the quad and the manifold.
So I redesigned this spacer to incorporate a throttle cable bracket.
Drawn in sketchup, printed 1:1 to confirm size and fit, exported the unfolded profile to DXF format.
Imported the DXF file into a CAD program and converted all the curved bits to arcs, this is because Sketchup creates curves as lots of small straight vectors which plays havoc with Lasers cutting machines.
The laser needs to move continously in a smooth motion or parent metal starts over heating and melting and the finish becomes poor.
A trip to the Laser man in the morning and picked up in the afternoon, luck of the draw they were cutting 3mm at the time.
The second spacer is for the rear quad to bring up to the same level.
 A trip to HPC and the parts have been black ceramic coated.

Installed under the quads.


Tuesday, June 17, 2014

Radiator & Fans

The radiator I had built by Shauns Custom Alloy see his web site. The construction, welding and finish is first class.
Its my design, with a few changes from the Classic Revival factory radiator.
For a start, I wanted to be able to lower the radiator out through the bottom of the car.
The factory unit is too wide to fit between the swaybar mounts on the chassis and would be quite cumbersom to remove through the top.
To counter for the reduced size (about 60mm in length), I raised the height as I dont need the space above the radiator for a cold air induction.
I also wanted a drain plug, and -AN fittings for the radiator hoses, a SPAL radiator fan on the back, and mountings on the front for the twin fan setup. I've heard these arent very efficient, but I like the look.

Twin Fans installed on the radiator mounts.

For the fan mount brackets, i had the local Laser Cutting man cut me parts for the motor and assembly mounts.
Most of the cost for this work is time based, so if you can do vector drawings yourself, and wait for when they do your material type run, the cost is very cheap for a quality custom product.

Here's a pic after bending in the vice and welding to some 19mm (3/4") RHS tubing.
The material is 3mm (1/8") flat, persuaded to bend with a hammer after applying some heat.

Pic of the can motor mount after painting.

The radiator is held in position by some CNC'd brackets and tube witha nylon insulator over mounting pins welded to the radiator tank.

The radiator base has 2 pins that locate into brackets on the chassis.

Supurb Tig welding by Shaun throughout the radiator.

SPAL fan on the back of the radiator will do the primary cooling.

The fan is surrounded in a custom polished aluminium shroud.

Lower radiator to pump hose, black Aeroflow -20AN fittings, black braided hose, and roll bar insulation to protect from any rubbing.

On the Radiator, I had fittings welded on for Sacrificial Anode, Earth Strap, additional Temp Switch or Sensor location if needed (Temp Sender unit on the Head for the ECU, which can switch fans on/off anyway).
Radiator purge (no filler point on the radiator due to access so will run a header tank)
Twin Fan Mount, Spal  Fan, Shroud, and locating dowls for radiator mounting.
The core is a 67mm PWR.