MK Indy Scuttle and Dashboard

So now the steering column and steering rack are installed and working, I can focus on getting the MK Indy scuttle and dashboard fitted to the car. This also includes the fitment of the ECU and fuse box mounting tray that sits under the scuttle. My friend Robert gave me a helping hand for this job.

Mounting Tray

The ECU and fuse box mounting tray is document quite well in the manual and is already precut and formed to the correct shape.

We clamped a couple of pieces of wood at the front of the chassis rails to help align the tray and keep it in position.

The manual suggests that foam is placed between the mounting tray and the chassis to stop rattles. I decided to use some 3mm rubber left over from the fitting of the fuel tank. I just cut some 25mm strips and used some double sided sticky tape to hold them in position.

We then clamped the mounting tray in position on top of the rubber and masked up the tray and marked out holes as per the manual.

We then drilled straight through the aluminium tray, rubber and chassis with a 4.9mm drill bit for the rivets. Then used sealed 12mm rivets to fix the tray in place.

Finally, I fixed some u-trim around the hole in the base of the tray to protect the cables that will go through here later.

MK Indy Scuttle

Next was to cut and fit the MK Indy scuttle. Time to unwrap another piece of bodywork that had been sitting in my shed for 2 years! It was in good condition and as expected. Phew!

We created a cardboard template for the right hand side for where the holes and cut out need to go in the scuttle fixing points. The rear tip of the scuttle needs to align with the vertical line in the side panel of the bodywork.

Then used this template to mark through onto masking tape on the scuttle. We used the same template in mirror image form for the other side, after double checking it was OK. This worked well. We were then brave and drilled the holes and used the Dremel for the cutout. After a bit of adjustment, it fitted well.

At this point we realised that the studs in the chassis are about 5mm too short. I really don’t know why they didn’t make these longer than you actually need so you can always cut them down. The scuttle fibreglass was very thick at the mounting points so I used a dremel to reduce the thickness and flatten the fibreglass around the mounting hole. Leaving sufficient space for a large washer which was filed down with a flat spot on one side. Eventually after a lot of fettling we had all 4x mounting points fixed with the thread almost coming through the nyloc. I think a bit of Locktite on the final fitment should be fine.

Dashboard

The dashboard was next. The first thing to do was to cut out around the steering column. The Carboard Aided Design (CAD) came in handy again. We used some cardboard and masking tape to mock up the shape that we needed to cut. We removed the plastic surround from the standard Mazda steering column. This allows the cutout to be much closer to the column. The steering column surround can be modified later to sit flush and cover the remaining gap.

We then transferred the CAD to the dashboard onto masking tape. After triple-checking the position I got out the dremel again and cut out the gap needed.

After some fettling and further cuts, the dashboard fitted nicely around the steering column. It was starting to look like a car now!

Dashboard Fixing Approach

Now the next bit was to fix the dashboard to the scuttle. Here there are 2x main options:

• Drill straight through the dash and into the scuttle and use small rivnut in the scuttle and M4 screws to hold the dashboard in place. This leaves the head of the screws visible on the dashboard, but is probably the quickest and easiest to do.
• Fix ‘large head’ fibreglass studs to the back of the dashboard with epoxy resin and the bolt them through the scuttle from the inside with nyloc nuts. This provides a nice clean finish to the dashboard so you can see the fixing points but is more time-consuming and difficult to do.

Which option do you think I chose? Yes you are right, the more complicated approach but it would be worth it with a nice clean look to the dash.

Working out the Fixing Points

The first this is did was fix the dash in position with masking tape and mark a line with a fine sharpie onto the scuttle around the dashboard. I also marked the inside with a chalk pen so I could see how much over lap there was.

The marking on the scuttle now allowed me to use masking tape and mark 6x holes around the scuttle for where the fixing point would be. My son then drilled 6mm holes at the 6x points around the scuttle.

I then cut down the edge of the ‘large head’ fibreglass studs with tin snips. I also slightly bent up the edge so they sat on the back of the dashboard flush.

One at a time I then inserted the stud into the scuttle and put a bit of blue tack on the large head. I then put the dashboard on aligned it up and pressed firmly to make sure the blue tack stuck. The dashboard was then carefully holding the blue tacked stud in position. I then marked the large head with a chalk pen. Then removed the blue tack and temporarily fixed the stud in the same marked position with gaffa tape.

I repeated this for all 6x studs each time putting the temporary gaffa tape fixed studs back in the relevant holes and then bluetacking the next hole. This approach worked surprisingly well. I soon had all 6 fixings gaffa taped in place and could do a test fit with the whole dashboard. A couple. Of minor tweaks to the angle of the studs and I was happy.

Permanatly Fixing the Mounts

I then used Gorilla Epoxy 2-part glue to bond the large head studs in position. This stuff seems to work very well with bonding onto the backside of the GRP body panels.

I also created a u-shaped strengthening bracket to go round the steering column cutout. This it to reduce the flex on the dashboard caused by the cutout. I made this from more CAD and 2mm aluminium plate. I drilled holes in the bracket to help the epoxy glue bind the support bracket to the back of the dash.

Once it was all set after 24hrs I fitted the dashboard to the scuttle. I did this with the scuttle off the car to make it easier without the steering column in the way.

A couple of the holes needed opening up slightly to fit perfectly, but over all it went in very well. I then test fitted the MK Indy scuttle and dashboard back on the car. I’m very pleased with the result!

there was one thing the manual suggested, which I hadn’t yet done, and that was to add some p-trim around the join to stop vibrations. I personally don’t like the look of the p-trim here but I do think it’s a good idea to reduce the chance of the panel squeaking.

So, I came up with an alternative approach which I think looks much neater but gives the same effect. I superglued a rubber trim to the edge of the dashboard, but made it flush with the edge so you can’t see it. I did the same for round the edge of where the clocks go also to stop any squeaks from vibrations.

Fitting the Clocks

I then moved into fitting the standard Mazda MX-5 clocks to the dashboard. This is where in the manual it says to simply tiger seal the clock to the dash. I didn’t like this approach and wanted a way of being able to remove the clock if needed. So I used the large head stud fixings again for the 2x mounts at the bottom. I then created a couple of aluminium brackets for the top and epoxy bonded them I’m place. Once the bind had dried I could secure the clocks in place with M6 nyloc nuts.

I am really please with the result, it is very secure and the clocks press nicely against the rubber seal which should stop any squeaks and rattles. I could then fit the whole dashboard back to the car.

Summary of Build Costs and Hours

Here is a summary of the costs and person hours (total number of hours for every person that has helped) for the build so far. This should hopefully help others with the planning of their builds, by providing cost and time actually incurred for this build. A more detailed breakdown of all the costs and hours worked on the build to date can be viewed here.

Person Hours Worked This Post
Fitting Scuttle	2 hrs
Fitting Dashboard	3 hrs

Car Build Costs This Post
Gorilla Epoxy Glue	£11
Big Head Studs M6 x10	£14
Neoprene Rubber Tape 15mm x 1.5mm	£8

Totals	This Post	To Date	All Posts
Person Hours Worked	5 hrs	409 hrs	409 hrs
Car Build	£33	£13,235	£13,235
Tools / Consumables	£0	£470	£470
Total Cost	£33	£13,705	£13,705