GD427 MK IV

GD427 MK IV
What my car should look like when finished - Stoneleigh 2015

Saturday, 24 February 2018

Wheels have Arrived!

My new Image Wheels arrived, so I obviously tried one on the car to see how it will look.  I went for CHB Image Wheels with satin black centres with nut covers and spinners.  I think they look better on than off!  Can't wait to get tyres fitted.




For tyres, GD recommend Michelin Pilot Super Sports for road use.  I initially was thinking to fit track day tyres, however after speaking with a few people, these tyres need to run at a high temperature to operate and to to this you need to drive the car hard.  For normal driving on public roads, you won't be able to get the tyres up to temperature.  The Michelin tyres get very good reviews online, and I have spoken to a few people who have them and recommend them.  I just need to buy some now.....  245/40/18 on the front, and 275/40/18 on the rear.

Fuel Supply - Complete

I fitted a couple of stainless P-Clips to the supply and return hoses that fit to the bulkhead fittings in the boot to satisfy the requirements of the IVA.


I was concerned about the smell of fuel in the boot of the car, along with the garage so I did some research online and came up with the following: 


  • Standard rubber fuel hoses won't leak fuel, however the fumes will pass through them.  For this reason, PTFE lined hoses need to be used to prevent this.  I used Goodridge 811 Series PTFE hose. 
  • The fuel tank requires to be vented for the filling and emptying of the tank in normal operation.  This basically means that the fuel tank is open to the atmosphere and therefore vents into your garage when the vehicle is at rest.  Normal production cars have systems that feed the fuel tank vents back into the engine through an emissions control system.  Since this is far too complicated to do, I chose a different method.
  • I found a two way valve from Newton Equipment Ltd (TPV8) that states that the valve remains closed when the engine is switched off, therefore preventing fuel smells in the garage.  The valve allows the fuel tank to breath when both filling and emptying and can be mounted in any orientation.  Please find a link to the spec sheet here.
I mounted the Newton valve inside the N/S rear footwell as high up as it could be mounted.  Hopefully this will clear the tyre!  This involved drilling a hole through from the boot and using some P-Clips to mount the valve.  On the outlet of the valve I fitted a standard fuel filter just more as a dirt filter to prevent dirt being sucked into the tank.  I used stainless jubilee clips with hose end covers.  I sealed the hose exit using some sealant to prevent water ingress.



Before fitting the tank and making up the last of the fuel hoses from the pumps, I covered the tank and boot in Silent Coat sound deadening pads.  These make a huge difference to the resonance of the fibreglass and the stainless fuel tank.  I really went to town with it, maybe a bit too much, but I didn't want to have steps in the carpet once it was laid.  I did the boot floor, wheel arches, rear bulkhead, main seating area, engine bulkhead and under the dashboard.  It has added a good bit of weight!



Once the fuel tank was in position, I cut the fuel pump wires to length and crimped the ends.  This will all require clipping into place, but I will wait until I finalise the rest of the boot lights.





Thursday, 11 January 2018

Fuel Supply

With the roll hoops fitted, I moved onto the fitment of the fuel tank connections.  I placed the fuel tank in the boot and planned what fuel hose should go where to minimise protrusions.

I have also decided to put valves in line with the supply and return since it seemed like a good idea at the time...

I loosely put together the y-piece, the valve and the elbow to see where the bulkhead fittings could be mounted.  This was slightly tricky due to the rear chassis bracing that runs up past the gap between the fuel tank and body.

I used masking tape to help see my drill points and drilled through for the -10AN bulkhead fitting for the supply, and the -8AN 90° fitting for the return.  This meant that I could now cut the fuel hose to the correct length and fit the hose ends.

Once cut to the correct length, the -10 supply hose was removed from the fuel filter to fit the hose end on the bench which was easier than doing it in situ.  The return line had to be done in situ, however the -8 fittings are easier to work with than the -10 due to the smaller size.

Once this was all dry fitted, I applied some sealant around the bulkhead fittings to help hold them in place.  I still need to fit a p-clip to each of the hoses.  Next job will be to make up all the short lengths of hose from the top of the tank to the bulkhead fittings.

There isn't a lot of room.....



Roll Hoops Fitment

With the body in position, I decided it would be good to get the roll hoops fitted.  This is one of the jobs that seem a bit daunting, since you have to drill large holes in the cars body!

I levelled up the chassis as best I could, by jacking the chassis up and placing it on axle stands with packers on top - my garage floor is far from level!

This took some time to get the chassis anywhere near level, but I wanted it to be right.

From underneath, with the rear wheels off, I could reach to drill up through the innermost mount holes with a right angled drill.  I made a bushing to fit inside the 12.5mm hole in the chassis which allowed my 6mm drill bit to be central.  Once these 2 holes were made, I placed some masking tape across the width of the upper boot floor and drew on a straight line between the 2.  I then used my cardboard template to mark the other 4 holes that were required.

Once I was happy with the position, I drilled the 6 holes in the upper boot floor - 4 @ 60mm, and 2 @ 50mm to allow plenty of clearance for the base of the roll hoops.  These lined up well with no problems. 

Firstly I made a measurement device so that I could detect the hole centre, and how far off I was.  I used a nylon M10 top hap washer, slightly padded out with a rotation of tape (taking care to ensure the tape ends lined up) and an AutoCad created 1mm Grid with centre line.  This was stuck to the washer with double sided tape.  Next the awkward bit......



I placed masking tape onto the underside of the rear bodyshell, so that I could project upwards a plumb bob mark.  This involved climbing in the boot, twisting, laying on my side / back / front to try to see what the plumb bob was doing.  I held the plumb bob just above the marker and using the thumb nail of one hand, held the string to the underside of the bodyshell and marked with the other hand the central point.  I did this for all 6 holes, and then double checked them.

They all seemed not too far away.....

I then drilled a 2mm hole up through the bodyshell at each mark to enable the plumb bob string to pass through to get a real reading.....



There was only 1 hole that was around 3mm out!  I drilled a new hole just to the side, and then it was spot on.

Now came the twitchy bit.  Rather than go for the 60mm holes and 50mm holes which would give the required 5mm gap all around the roll hoops, I went for 50mm for the front holes and 38mm for the rear (the exact diameter of the roll hoops).  I drilled the 50mm holes first and opened them up very slightly with a drum sander so the legs could just go through.  I tried the first hoop in and it fitted!


I then drilled the hole for the rear leg (38mm) which again, after being opened up a little, fitted nicely.  Or so I thought.....

After I had fitted both roll hoops, I tried to tighten them down.  I realised that they wanted to pull forward slightly.  I had to remove them and elongate the holes towards the front of the car a few times until the hoops fitted.  This possibly means that the chassis wasn't perfectly level prior to the drilling!

Not to worry, once the required 5mm gap was drawn all around the bars, the biggest gap I had was 6mm.  Well within tolerance of the large rubber grommet that gets fitted along with the aluminium cover.  I still have to fill the hoops with expanding foam to help deaden the noise, and I probably won't finally fit the hoops until the boot carpet has been fitted.

All in all a job well done that was probably the job that I feared the most! 



Bodyshell Fitted

After making sure I had done everything on the chassis, I organised for some friends to come along to lift on the body - hopefully permanently this time!

I removed the bolts from the radiator mount and held the radiator back using some bungee cords to give as much clearance at the front as possible.



Everything was ready and so it was just a case of rolling the shell outside, spinning it around the correct way, and then lowering it onto the chassis.  I obviously supervised, while the 4 others lifted and guided the shell in place.  My son was the first to sit in to try out the passenger's sitting position.

It has certainly cleared a bit of room in the garage, basically going from 2 cars down to 1.  I do now have a spare bodyshell trolley........

Once the body was lowered, I fitted the windscreen.









I then passed the ECU connector and loom in through the from bulkhead into the back of the dashboard.  It was a bit tight getting it through, however I think the finished product is very neat in the engine bay.



I then fitted the air filter prior to re-bolting the radiator mount in place.  I actually dropped the radiator from its lower mount to get the filter in.  The filter is held in place with the rubber hose and stainless jubilee clips whilst being pushed up against the body by the radiator.


An excellent milestone!

Driving!! (Just Pretending)

A friend and work colleague came along for a drive in the car.  We had to use a lot of imagination, however it was good to pretend to feel the wind through our hair!


Starter Cable

I upgraded the starter cable to 50mm squared which should provide enough oomph to turn over the LS7.  I installed the positive to the starter a while back, and covered it with a temperature proof sleeve to protect it against the heat.

I decided to run a 50mm cable directly from the battery to the engine block, and then a short cable from the engine block to the chassis.  I thought this would be the best for maximum current to the starter.  I used a M10 bolt to fix it to the block, and a M8 one to fix it to the already fitted rivnut on the chassis.

I will run the cables into the battery compartment later.





Fuel Pumps and Sender

I bought some Blue Hylomar sealant which is fuel proof to put around the bolts and gaskets on the bolts that go onto the fuel tank.  The Aeromotive kit for the fuel pumps system came with a foam style gasket and nylon washers an lock nuts.

The VDO sender came with a rubber gasket and I used stainless M5 button head set screws with spring washers.

For information, the VDO sender showed 85.5 Ohms when empty, and 4.2 Ohms when Full.  I may need this when ordering gauges!



I then thought I had better service test the fuel system before fitting the body.  The y-piece fuel fitting under the transmission cover being the one of most concern.

I put some hose fittings onto the end of the fuel hose at the rear and connected up the supply hose, with the return temporarily going into a waste tank to flush the lines.  The tank was then filled with some fuel - enough to feed the pump.

I opened the garage door to ensure there was plenty of ventilation before connecting the pump directly to a battery.  I pulsed the pump a little, just to ensure there were no leaks anywhere.  Once I was happy, then I let some more petrol flow into the waste tank.  I then connected the pump to run full time.

There were no leaks!!  My son ensured I had not missed any.

I then tweaked the fuel pressure regulator to reach the required pressure of 58psi.  This may be tweaked later on when on a dyno, but this is now set.

Very happy with the fuel system, so shut off the pump, and drained down what I could of the fuel lines.  This now means my garage smells of petrol.....  And my clothes....






Gearbox Oil

Before fitting the body, I thought it would be a good idea to fill up the gearbox with oil.  I bought some Dexron III rated oil as stated on the gearbox.

It took 3.5 litres to fill up to the plug level.

I used a Sealey transmission oil filling system which worked really well and didn't create a mess.

Another job done!





Cylinder Head Steam Vents

There are a lot of theories regarding the steam vent system of the LS engines, and whether to leave the rear 2 blocked off or not.  The theory is that air pockets form in the top of the head and can create hot spots.  I think it depends on how level your engine is whether you should have them open or not....

I decided to play safe and buy a steam vent kit from the USA which links all 4 vents back to the header tank.  I had to relocate the N/S lambda sensor connector bracket that I placed over one of the ports.  I just made a new stainless steel bracket to mount it and bolted it to the block with a short M10 cap screw.

This also meant that I had to drill out the small plug that blocks off the port on the rear of both cylinder heads.  I used a 3mm drill bit with lots of grease and a hoover to slowly drill out the plug.  Once I was down a little bit, I tapped the hole out to put in a M4 bolt.  This then allowed me to plug out the plug without causing too much mess!

I gave the water jacket a good hoover, to ensure no swarf had entered in.

I plugged the holes with paper towel temporarily to prevent any further entry of bits.  I will provide an update once I have fitted the steam vent kit.


Roll Hoops Test Fit to Chassis

I thought I had better try and see if the roll hoops fitted before fitting the body and finding out they require tweaking!

These fitted with no problem.  These use a stud in the outermost holes (Above the shock absorbers) and bolts in the others.  These are 1/2" UNF.

I made up a cardboard template to enable me to mark out the holes in the boot floor once the body is fitted.  This will be used later!




Fuel Rail Hose Supports

Since the IVA requires all hoses or wires to have fixings at a minimum of 300mm, I had to create some more mounts for the hydraulic clutch hoses & fuel hoses, especially around the fuel rails.

I fabricated some twisted stainless brackets to fit underneath the transmission tunnel, and some small brackets to fix the fuel hose to the fuel rails.  I drilled and tapped holes for M5 button head set screws and used stainless P-Clips.

I cable tied some of the gearbox wiring to the fuel hose supports since I thought this would be adequate.

I then re-affixed the transmission tunnel cover once this was all done.