Saturday, 19 July 2008

Fuel Pump Plumbing - 2

Time to finish fitting the fuel pump and filter. Started off by drilling the holes for the brackets and a hole for the fuel pipe grommet:
The pump and filter were then fitted on their respective brackets and the fuel outlet hose made up and fitted:
The hose changes to normal rubber hose as it exits the boot and fits between the chassis and body as shown. I've left this hose long for now so I can pump fuel through from the tank once everything is finished just to ensure everything is clean before connecting up to the chassis hard line:
The last job was to trial fit the tank and make up the feed hose. All the hoses are -8 apart from the fuel pump outlet which is -6.
I'm quite pleased with the results..... just need to figure out how to make a neat job of boxing everything in.

Wednesday, 16 July 2008

Fuel Pump Plumbing - 1

Made a start on the fuel pump / filter plumbing. In the boot I'm using TFE racing hose and fittings. This stuff ain't the cheapest but due to the special lining is impervious to fuel vapour (unlike normal braided hose) - so fingers crossed no smelly boot!

I fixed the brackets to a piece of MDF as it was easier than working in the boot:

Tuesday, 15 July 2008

How to over-engineer a simple bracket for the fuel pump!!

Now I blame this latest escapade on not having a windscreen yet!

The fuel pump and fuel filter need to be mounted in the boot - a simple bracket should suffice. However, I've come across a few Cobras where the noise of the fuel pump was pretty noticeable. I have a carter pump which is quieter then some and is mounted by three rubber bushings. I decided that this wasn't enough and I really should isolate the pump from the bracket!
So after a couple of hours I managed to produce a kit parts:
The nitrile rubber sheet is sandwiched between the bracket and the back piece and provides the mounting for the pump frame:
The pump frame is then bolted through the rubber using large washers to sandwich the rubber and leave a 3-4mm annulus of rubber which can flex slightly to absorb noise and vibrations:

And here's the finished item:

And this is where it will fit - with a similar bracket below to take the fuel filter:

When all is finished this little lot will need boxing in.

Sunday, 6 July 2008

Fitting the Roll Hoops - 5 - The Other One

Having done it once, it was time to do it all over again. I used exactly the same process as before and did not discover any problems in doing this.

This time it only took three hours to fit the hoop - half the time of the last one. And here's the end result:

Now I can relax!

Saturday, 5 July 2008

Fitting the Roll Hoops - 4 - Here we go!

Time to put the plan into practice. Having marked the underside of the boot off the studding and drilled a pilot hole upwards I then drilled two 25mm dia holes to expose the ends of the studding:You can see in the next photo the 6mm pilot hole in the studding to centre the hole saw mandrel. The piece of MDF you can see in the hole is the boot template being used to space the studding at the correct centres.These holes were not expected to be concentric with the studding due to the difficulty of marking the exact centre of the studding on the underside of the body from within the boot. The next step was to cut the two 51mm dia holes for the main legs:

These holes were gradually opened up with the Dremel until the bolts could be fitted and tightened without the legs binding on the edges of the holes. The hoop was fitted the wrong way round so that the back leg could be ignored for now:The MDF template was used to "spot" the pilot hole for the back leg. It was made from the leg spacing gauge as shown below:Because the hoop is being trial fitted the wrong way round you must remember to flip the template over when "spotting" the back leg hole on the body.

With the hole "spotted" a 38mm dia hole was cut in the body and the whole process of opening out started again until all three bolts could be fitted. The back leg needed to be pulled out a couple of mm and this was done by packing between the legs in the boot.

So the hoop is in but the holes are a but untidy. This was remedied by scribing round the legs using an M10 washer to give a 5mm clearance hole:

It is then a simple task to open out the holes to the scribed line. The best method is to use an 80 grit flap wheel in the Dremel -use 15,000 rpm for removing the bulk of the material and 10,000 rpm for finishing off. The end result is three nicely finished, perfectly circular accurately centred holes:

The roll hoop was loosely refitted and the grommets installed - purely as I wanted to see what it would look like. I found the 5mm clearance hole just about spot on for getting the grommets to fit snugly:

So it would appear that the plan has worked. Feeling flushed with confidence I decided not to fit the other hoop today - over confidence leads to mistakes. From start to finish it took me 6 hours to fit one hoop. But most of that time was spent double and triple checking and it can get a bit time consuming lifting the hoop in and out whilst opening out the holes a little at a time.

So to finish here's some gratuitous shots of the finished article. I don't think I'll bolt the hoops down permanently yet as they will only have to come out to fit the boot carpet.

Friday, 4 July 2008

Fitting the Roll Hoops - 3 - The Plan

Right then, here's the plan:

The GD method of cutting the top holes involves drilling pilot holes, using a plumb bob and adjusting as necessary. It is not possible for me to get the body level in both planes when the whole car is up on axle stands. So a different method is required.I bought some M12 studding - checking it was straight - and cut some lengths. These have been bolted to the roll hoop mounting holes. I will then mark the underside of the body and drill a small pilot hole from underneath. Using the pilot hole I will then cut a hole from the top big enough to expose the end of the studding. One piece of studding has had a 6mm hole drilled in the end of it to take the mandrel from the hole cutter.

I will then cut a 51mm dia hole above each piece of studding. This is the exact same size of the roll hoop legs. By turning the roll hoops through 180 degrees the back leg can go down into the cockpit and can therefore be conveniently ignored whilst the two main legs are positioned.

I doubt if the two holes thus drilled will match up exactly to the roll bars so I will open the holes out as required until the hoop legs can be passed through. The holes will be further enlarged until the fixing bolts through the chassis can be installed.

I will be left with an odd shaped hole but by then scribing round the leg with a washer a concentric hole can be marked and opened out. This last bit is how GD do it:What can go wrong?:

1: Studding not square to chassis - this a risk I'll have to take as there is nothing square in the boot that I can check against. I've checked the studding bolted to a piece of MDF and it is as near as damn it square when tightened up.

2: Roll Hoop legs not parallel - checked this with a home made tool shown below - less than 1mm out over the embedded length:3: End up opening the holes out so much that the grommets don't fit properly. I cut some holes in the piece of bonnet I cut out for the scoop:
I found that I could go up to a 64mm dia hole and the grommet would still fit nicely. So that gives a difference from the roll hoop of 13mm. Therefore the accuracy of marking the centres on top of the body using the studding has to be within 6.5mm or the resulting holes would be too big for the grommets to fit.

Now the only way that this error could occur would be down the studding not being square. For it to be out by 6.5mm over a 300mm length would be pretty drastic - and hopefully obvious!!

I wouldn't say that I am 100% confident at the minute but I'm going to sleep on it before cutting commences tomorrow.

If you think this plan is fatally flawed then you best leave a message quick!

P.S. The third back leg needs a slightly different plan as the fixing bracket is free to rotate - more on that later

Wednesday, 2 July 2008

Fitting the Roll Hoops - 2

For those of you expecting big holes cut into the upper body - sorry - you'll have to wait.

Instead I cut out the lower holes for the nearside hoop - so that's all the lower holes done:

Tuesday, 1 July 2008

Fitting the Roll Hoops - 1

Time to start on the dreaded roll hoops!! Now Craig at GD convinced me that it is easy enough to fit the roll hoops once the body is on....... well we are just about to find out.

Firstly it's time for the rear wheels to come off - if you look at the photo you can see it is possible to get an axle stand under the rear of the diff carrier. To be doubly safe (as you can see on the right) I also packed under the body just in case:The first step is to transfer the centres of the fixing holes in the chassis onto the boot floor. This can be done easily using a 1/2" UNC bolt cut down and drilled down its centre - this centres the pilot drill nicely:The next step is to cut out two oversize holes for the main legs of the hoops. I used a 63mm hole saw which gives a decent clearance around the 51mm main legs:Next I cut a piece of 9mm MDF and transferred the hole centres from the chassis onto it and drilled a couple of 1/2 inch holes. I checked the hole centres of the hoop against this template and they seemed to be cock on (the hoops are CNC bent and the plates with the fixing holes are welded on using the chassis jig). By bolting the hoop to the template you can mark out where the bracket for the back leg goes:By drilling a pilot hole in each corner of the cut out, and fitting the template to the two main leg holes you can transfer the rectangular cut out onto masking tape on the boot floor. With the trusty Dremel you can then cut out a clearance hole for the bracket:

On the Jag Chassis the back leg of the hoop fits to a bracket that bolts through the shock mount as shown below:

In the vast majority of cases this bracket will foul the boot floor so you need the clearance hole for the bracket rather than just the tube. Clearance holes are needed as you have to remember that the body is mounted to the chassis via rubber mounts so there needs to be some allowance for relative movement between the two.

It's a bit awkward working within the confines of the boot and you will need to wear a decent mask to avoid breathing in copious amounts of fibreglass dust.

Also don't worry about the gaps between the floor and the hoops / bracket - I've got that sorted you'll just have to wait!

Just need to do the other side next.