Speedometer Calibration

Now that the car is pretty much complete and ready for testing, I thought I had better calibrate my Smiths Speedometer.

I bought the Caerbont Automotive Instruments Smiths Electronic Speedo (200mph anti-clockwise).

To be able to calibrate the speedo, you need to follow the instructions very carefully. (Online Download)

The first piece of information requried is the rolling circumference of the rear tyre.  I stuck on a piece of masking tape onto the tyre and drew on a straight line.  I then placed masking tape on the floor with a similar straight line.  From the starting point of both lines touching, I rolled the tyre across the floor and when it went full circle, you guessed it, I placed another piece of masking tape down with another line.  Measured between the lines I got a measurement of 2087mm.  This is for the 275/40 R18 Michelin Pilot Super Sports.

Since my speedo is in MPH, the instructions request "Wheel revs per mile = 63360 divided by the distance travelled in inches".  

To convert from mm to inches you need to divide 2087 by 25.4.  This gives the answer in inches (82.16535433)

Therefore the Wheel revs per mile for my car is 63360 / 82.16535433 = 771.1279348 (give or take a few decimal points!)

We can now figure out the calibration number with the following calculation "Calibration number = (wheel revs per mile/km) x (diff ratio) x (number of magnets or bolts)"

The diff ratio for my Dana Spicer Hydratrak is 3.07:1

The VSS for the T56 Magnum has 17 pulses per revolution (That's what most people seem to confirm on the online forums!)

So, finally, the Calibration number sum of the speedo is:

771.1279348 x 3.07 x 17 = 40245.16692

The instructions state "the calibration number you have calculated should be rounded up to the nearest whole number" so my final Calibration Number is 40246.

To enter this data into the speedo itself,  as per the instructions:

"The calibration mode is selected by switching on the ignition while simultaneously pressing the trip reset button. The pointer will travel to full scale and return to zero. If the button is released before the pointer returns to zero, the manual setting procedure will be selected and the LCD (ODO.) will read ‘SET PPU’. If the button is released after the pointer returns to zero the ‘drive to set’ mode is selected and the LCD will show ‘DTS PPU.’  At this point, pressing the reset button momentarily will toggle between ‘SET PPU’ and DTS PPU’.  

Manually Inputting The PPU Number

Set the LCD to display ‘SET PPU’ as described above.  Press the reset button for 2-3 seconds, the LCD will show the calibration number currently set. Each digit within the calibration number will flash in turn for approximately 2 seconds. When a digit is flashing, each depression of the reset button will increment the digit by one. Once the last (right-most) digit has been set/reset, the whole number will flash. Press the reset button and the LCD will display ‘DONE.’ After 3 seconds the LCD will display ‘SET PPU,’ the setting is now complete. Switch off the ignition."

It is fairly easy to setup once you know all your figures - as long as you remember to press the reset button when all the digit flashes to ensure the number you have put in is stored...  When I double checked that I had put the correct number in, I found that the default number "008380" was still there.  I re-did it and remembered to press the reset button when all digits were flashing.  I have since re-checked, and my number has been stored.  I will test it properly once on the road compared against the sat nav.

Windscreen Footwell Covers

I wasn't sure how to deal with the windscreen that protrudes down into the footwells.  Since I have power steering, this differs from the standard GD frame which will differ from the usual covers that I think they can provide.  I will just make ones.

Using card, I created templates so that these could be made out of stainless steel.  My friend created these from my template - only a small bit of welding required.  The edges are nicely rounded.

I prepped them and sparayed them semi-gloss black, along with the heads of the bolts.  The bolt that holds them on is the lower Windscreen bolt.  I felt that was the neatest way to fasten them on.  Fairly finishes off the footwells.

Boot Carpets

The last bits of carpet to install are for the boot.  There are quite a few pieces, so I laid them out and tried to figure out what they all were.

Since I have a larger fuel tank than normal, I asked Meena to add on material to the standard carpet so it would fit my tank.  This was done so the seam is on the edge of my tank.

I started loosely laying all the pieces in to see how they fitted.  I realised I was going to have to create a cover over the top of my fuel pumps just to fully protect them.  Also, where the fuel hoses run and I have a couple of valves in a void on the passenger side, this would be best closed in.  At the driver's side, this is a perfect size to hold my Windows 10 tablet in it's case, so this will remain empty.

Using some 20mm plywood, I cut a perimeter support around the pump assembly.  Then upcycling an old Land Rover Series 3 hardtop, I cut a piece of aluminium as the cover.  I stuck on some loop velcro on the bottom, and glued the rest with a mix of superglue for the wood, and CT-1 for the rest.  I sprayed it black although nobody will see it.  I used some edging strip to protect the wires / hoses.

For the side void, I just cut a piece of aluminium and screwed it onto the bodyshell.  Again, edging strip was used for the wires.

Now that everything was ready to go, I felt the easiest bits of carpet to start with were the upper side pieces - these go behind the outer roll hoop bar onto the rear wheel arch.  Minimal trimming required.  A bit of triming required on the leatherette flap around the roll hoop, and on the passenger side a bit of trimming due to my fuel pump cover.

Carpets were all glued in using EvoStick Timebond.

The next pieces I chose to glue in were the rear corners.  These are quite odd shaped, but are flat and require to curve compoundly.  With the floor carpet in place (Mine doesn't fit since my tank is bigger - need modificaiton!) as well as the rear panel, I marked where the rear quarters best fitted to ensure everything was covered.  These were glued in with the help of a clamp.  I trimmed pieces out of the carpet to aid the curvature and remove the ripples.

The main upper carpet which covers the top of the fuel tank as I mentioned had an extra section added in.  The seam fits at the correct location.  The only issue is, the side wings of the carpet are too short to cover the rear wheel arch.  So, I strategically cut the wings off the big carpet so that I could glue the wings on separately on the wheel arches.  The main carpet could fold around the fuel tank around 50mm so you can't tell from the boot opening that the carpet has been cut.  For the passenger side, I glued in off cuts to fully cover the new aluminium panel and the side of the fuel tank.  I have left the driver's side for my tablet.

For the main carpet, it has pre-cut holes for the roll hoops which velcro closed.  This needed minimal tweaking to fit due to my fuel pumps.  I glued the edga along the top of the tank and the front of the tank, but left the main part on top loose.  The carpet isn't too flexible, but through time it may follow the coutour of the fuel pump cover.

The boot floor carpet, the one that immediately meets you when you open the boot, is standard GD size.  Since my tank is bigger, I had to notch out the tank shape in the carpet.  I measured and marked a few times to double check I wasn't going to cut it wrong.  Once cut, it fits neatly up against the tank carpet.

For the rear section of carpet that covers the rear lights, this passes underneath the boot latch.  I had a look and felt that if I was to use self tappers, it would pass through to the outside...  I decided to mould in a boss with stainless nuts.  I set everything in position and made a mould and laid in P40, and then P38 fibreglass.  I left this to cure and then sanded it down a bit.  The boot latch now fixes using button head set screws.

The final part for the boot was to fit the seal and also some edge trim.  The seal is an adhesive type so I just slowly stuck it on - I made the join line up with the boot striker rather than the centre of the car.  I felt that having a different line might make it all look askew!  The seals and edging strip faily finish off the boot area.  All in all, a good job, and the boot is still big enough to get a lot of stuff in it.

Overflows

I installed a hose on the coolant expansion tank to route it to a safe location under the car in case any excess pressure wasa observed.  I fastened the hose to the chassis using P-Clips.

I also installed a hose onto the windscreen washer tank - just for aesthetics so it looks more symmetrical.  It won't see any pressure.

WHilst in the engine bay I fitted stickers to the brake & clutch fluid reservoirs reminding me to use DOT 4 fluid..

And, in the same small bag of stickers there was one for the brake adjuster.  I trimmed that slightly and stuck that on too.

Time to Reflect

For the IVA rear relfectors are required.  After looking at various people's versions, I thought for now I would make a simple bracket that bolts on under the brake light.

I created a pattern on a piece of card, and then once happy cut it out from a sheet of Stainless Steel.  The holes were bored, and everything was rounded off and polished with the polisher.

I then moved onto getting the ID plate fixed to the bulkhead.  I have a fairly empty bulkhead, so placed it nearer to the passenger side.

A front number plate blank was made from a piece of plywood just to mimic where the number plate will finally fit.  This is currntly screwed onto the bar using P-Clips. Not sure how I'm going to fit the plastic number plate - if you have any ideas please let me know.

I also changed the engine oil - had a petrol smell so I will have to check after getting the engine setup on the dyno.  Since my LS7 has a batwing sump from an LS2, it isn't 100% straight forward.  The oil spec is easy enough, it needs to be GM4718M 5W30.  I used Comma Syner-X Fully Synthetic.

The oil filter needs to be the one from the LS2 which is an AC Delco PF46 (Or equivalent - In my case Mahle OC 999).  

The engine takes 6 litres of oil.  

Shetland Classic Motor Show 2024

I had my car at the Shetland Classic Motorshow back in 2018 - it was merely a rolling shell that couldn't run.  I was hoping that it would have been finished long ago and that I would be able to fully drive the car to the show (Approx 10 miles away).  It wasn't to be - I had to utilise my trailer again, but that is why I bought it!  At least this time I could drive the car in and out of the trailer.  Next time the show is on (2026) I will be able to drive her there.  If you are keen, keep an eye on the show here: https://www.facebook.com/ShetlandCMS.  Maybe we can have a GD stand in the future!

I just had to finish off a few things to make the car presentable.  I clipped on the harnesses, and gave her a good polish.  Spinners were put on the wheels to finish them off.