This blog is intended to document the build of my Gardner Douglas Mk4 Cobra; partly as IVA evidence, bit primarily to help others learn from my mistakes and/or successes.

I will endeavour to post as often as possible, with a view to entering a single post for a particular element of the build process, however inevitably some things may not be completed in one go. All posts will be tagged so it should be easy enough to find the information you seek.

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Monday, 29 February 2016

Body Collection Day

Well the day finally came to collect the first bits of my GD Mk4 Cobra and I woke up early like a kid on Christmas day. 

I had originally booked a Luton van as others had, but I decided to use my trusty ex-caravan trailer instead which allowed me to use company fuel and save a precious few pounds. A couple of pallets were screwed to the deck with some rubber matting on top to stop it sliding around which worked well. 
The rest of the stuff went in the boot protected by some old duvets and foam mattresses.
And here it is in it's home for the next couple of years. 

Thanks to Greg and his Dad for helping to load it on the trailer. 

Looking forward to getting started.... 

Wednesday, 17 February 2016

Body Skate

I should hopefully be picking up the body on 28th Feb so it's time to make sure the garage is ready to receive it.

I bought a new Halfords Industrial tool box (in orange of course) to properly organise my tools and also free to cupboard space for storing the many Cobra bits which will soon need somewhere to live.

Tonight I decided to build a skate for the body to sit on and used Dale's blog as a starting point, but just used what timber I had lying around rather than buying new.

This is what I used:
- 2 off 1370 x 610 x 18mm thick plywood
- 4 off 250mm legs cut from 5" square post
- various off cuts of 18mm OSB as side bracing
- 5 off 3" square posts
- 4 off 8" (200mm) swivel and braked castors
- Loads of screws and a few bolts

1. I placed the plywood on the floor and cut some of the OSB to form a box the same size as the plywood.
2. The 5" square posts were then placed in each corner and fixed to the OSB with drywall screws from the outside.
3. The 3" square posts were cut to length and placed around the edge in between the legs. I then screwed through the OSB sides and plywood top in to these. The 5th one was placed acros beneath the join the ply.
4. Two strips of OSB were fixed across between the feet.
5. The casters were then screwed and bolted to these cross pieces. 

This has given me a skate 1220mm(W) x 1370mm(L) x 530mm(H) which should give me a good working height. 

OSB used to create a box giving lateral stiffness 

Here you can see how the 3" square posts were used

8" casters should make it easier to roll outside if I need the garage for something else

Almost finished, just waiting for some 3mm ribbed rubber matting for the top

Monday, 15 February 2016

Out of the mould

So the body has been slightly delayed due to one reason or another, however it's now out of the mould and looking fabulous (in my opinion). Hoping to collect it in the next couple of weeks.  

This is still inside under artificial lighting so looks slightly lighter than it actually is. 
Probably a closer colour representation. I love the stripes. 

Tuesday, 2 February 2016

Gear Box Options

So the final decision of Orange with Carbon Fibre stripes has been made and the body is in the mould as I type.  I was hoping to pick it up this weekend, however one thing or another has delayed proceedings slightly, not to worry as there's still loads of prep and research to do.

Another decision I have already made is that I will be using an LS3 but as an engine and gearbox combination from new will set me back around £12k I've been exploring the possibility of a second hand unit.

LS3s are used in a myriad of American Muscle cars and a fairly readily available in the US, but after paying a minimum of $9k + shipping + import duty + VAT it's not that viable so I've ruled that out.  As far as I know the only UK sold car to come with an LS3 is the Vauxhall VXR8 which aren't exactly ten a penny, so finding a pullout is tricky, but I think I've succeeded.

There's a guy called Gary who runs a site called www.LSXV8.co.uk and is about the only UK breaker of Monaro's and VXR8s.  I got in touch and was surprised to hear that he had a low mileage (28k) 2009 LS3 with 6 speed manual available which has everything except ECU and loom, lovely.

Whilst I wait for him to put it back in a car so I can see/hear it run my thoughts turn to the gearbox and it's many guises.  He tells me it's a T56, however there seems to be about a million different variants with a million more gear ratio combinations and shifter locations, so I delve deeper....

After many hours/days of trawling Google and various forums, I 'think' it is either a TUET-2066 (T56), TEUT-2100 (T56) or TUET-10310 (TR6060) but am still waiting  back from Gary to confirm the correct part number.  In the meantime I have created a spreadsheet to compare the above three options and the T56 Magnum which GD use.

Tremec Transmission Comparison - Cruising

One of my considerations is the usability of 6th gear for cruising so you can see the relative RPMs at 80 MPH (not that I would actually drive that fast on UK roads!)  All are under 200 RPM so will offer reasonable full economy on long journeys.
Tremec Transmission Comparison - Speed
This time I've left the RPM the same so you can compare the speeds in each gear, the TUET2100 is my least favourite as I think 6th would almost become redundant so that is out.  The TUET2066 is a better set of ratios but reliability has been questions in the VXR8 community which is why Vauxhall ended up replacing a lot of them with TR6060s under warranty.

The TUET10310 is said to be much more reliable a less agricultural than the standard T56 so this would be my preference if it turns out that is what is currently attached to the engine, however both the T56 and TR6060 in a VXR8 would have a remote shifter so this would need to be repositioned.  Worst case I may end up having to get just the engine and sourcing a new T56 Magnum.

The spreadsheet automatically calculates everything by changing the ratios, RPMs or wheel and tyre sizes.  If anybody out there wants a copy let me know.