August 2024. Our new, Issue 37 Catalogue revision has been pretty-much a full time job for the past year but it has recently been published leaving me some spare time to plough-on with our, somewhat neglected P4 build. We've re-roofed and insulated our workshops so at least the coming autumn and winter will be a little more bearable for my 70 year-old bones. 

Although the physical build hasn't advanced much recently, I walk past the car several times a day and the next stages of the project are never far from my mind. I've begun to plan the installation of the 'Ron Francis' engine loom and fuse board, along with the original, reflashed, Ford ECU and the remaining wiring, for which I'll be using one of our Wiring Modules. A sensible home for these components will be inside the drivers side sill section and behind the driver's seat - a job much easier if the centre tub is fitted.

Of course, the tub has been on and off a couple of times during the chassis construction and the roof re-shaping, but this time will be the last time - fully bonded and riveted, with the front-to-back water pipes and the fuel tank installed at the same time.

The picture above shows the centre tub with all the bare, glass fibre modifications from lowering and widening the roof area. There's still a lot of rubbing-down and filling required before paint and it'll be much easier to do it at this stage - outside in the few, warm, dry summer days we may be blessed with this year.

Here's the widened and lowered roof and my big, powerful 240 volt Makita sander. It has already been roughly sanded but still has low areas and unfilled rivet holes from the grafting process. A wash with acetone followed by a careful and thorough blow with a full pressure airline exposed all the holes and low areas to be filled. You can see, in the lower left corner some of the saw cuts made to re-profile the roof. They, and the inside of the roof have all been reinforced with a strong GRP layer leaving only the 'saw' lines to be filled and levelled.

It's pointless, at this stage, to aim for a perfectly smooth and level finish because, a: the shape may change and settle a little when the tub it fitted and, b: it will be blended and profiled together with the matching section of the tail and the doors. But it's worth spending some time getting the basic shape 'almost there'. 

Here, I've skimmed the low areas with body filler and sanded it down. I'm spraying a very light 'dust-coat' of black aerosol.

I glued a strip of (yellow) 60 grit abrasive to a 600mm  x 50mm strip of 6mm MDF. It's flexible enough to bend and follow the shape of the roof in all directions, removing the black dust coat from the high points and leaving the lows black.

After a blast with an airline, a  'tack-rag' removes all remaining traces of dust ready for another light skim of filler in the low areas

A heavy coat of filler primer will fill the pinholes and help identify low areas

The grey areas are light skims of a one-component fine filler/stopper, after another rub down with my flexible MDF sanding plank. The old trick of closing your eyes and running the flat of your hand over the surface will pick up minor imperfections that you can't see.

Resin, fibrefil and regular P38 filler (all available from our online shop) were used to fill and perfect the shape of the mid window reveal. This would be very difficult to work on when the tub is fitted so best to do it at this stage. You can see, in this picture, the layer of 3mm 'Coremat' reinforcing fabric, bonded on the inside of the roof.

Various tools, like this sanding block,  ......

..... and some 40 grit abrasive paper, glued to this piece of 25mm dowel, ....

.... and, of course an index finger filler-spreader all played their part in a neat and proper job.

Another job to do before fitting the tub is to dress and pre-fit the mid window. Most previous cars had a laminated glass mid window but, because of the new shape of the reveal I decided to use a 6mm thick acrylic one that I had left on the parts shelf.

I started by making a paper template of the reveal, taped onto the outside then drawing around the reveal from inside the tub.

... then trimming to shape - first with a bandsaw, then linishing.

Here is is pre-fitted. Final bonding-in can be done after paint.

Another job that'll be far easier before the tub is on, is positioning and mounting the seats through the steel floorpan. I covered making the runner frames in an earlier post and we know that they fit and will be comfortable but I have not determined their exact position or drilled the mounting holes. The P4 cockpit is snug but there will be some luggage space in the void behind the seats so they will have to be free to move as far forward as possible to access the space

I designed the seat runner frames to mount 'around' the GRP seat bucket leaving only a couple of millimetres clearance between the seat bottom and the floor, to maximise clearance between head and lowered roof. One thing I omitted to take into account is the height above floor level of the seat adjustment lever. A chassis cross member, in the middle of the floorpan restricts full forward movement of the seat because the adjustment lever is on the same level. So, to raise it, I cut, and re-welded the lever bar on top of itself and bent the end of the lever upwards slightly to clear the cross-tube. 

Here are the seats in place. They'll eventually be re-trimmed and fitted using M8 dome-head bolts with the heads under the floorpan and the nuts inside the seat runner channel that you can see in the above picture

The area you're looking at here is the mid bulkhead - behind the seats and in front of the engine. I've already cut and drilled the two 1mm aluminium panels for the lower half. The top half - up to the mid window is a one-piece, moulded GRP panel. If ever access is needed to the front of the engine - belts, water pump, plumbing etc., it'll be much easier if the panels are removable. So, I've opened up the 3mm pilot holes to 6mm  and I'm installing M4 stainless rivnuts with our excellent swivelling head rivnut tool #KASWIV.

I've already made the panels that fit here but they'll need some sound and heat insulation on the engine side - as will the GRP upper panel. They will both be relatively easy to fit when the tub is on.

But there are other cockpit panels that must be final-fitted before the tub goes on. The upper, aluminium, dash side panels are two of them, and this is what I'll line them with - Dynamat Xtreme. This pack contains nine pieces 18" x 36". 36 square feet in total - plenty for the P4. It will absorb and dissipate heat and vibration from aluminium and GRP panels. It's quite heavy and dense but the extra weight won't be an issue in this car.

The panels are already made and secured - the upper one is temporarily fixed with Clekos and will have the Dynamat on the inside. The lower one is flocked on the inside and finan-fix riveted. It will have Dynamat on the outside.

First job it to make a paper template for the upper panel.

Another job before the tub goes on is to run the heater and aircon hoses. The engine was supplied with the AirCon compressor already fitted fitted but it had a simple rectangular blanking block over the in/out ports. I modified four of our AirCon fittings and silver soldered them together and to the block. The dash 8 and dash 10 threads will accept the charging ports or hoses.

Fifty two quids worth of Zinc plating and clear passivate. 

 I have successfully used one of our header tanks (#HTHB) on a previous build so I removed its existing mounting brackets and fabricated a new support bracket from 3mm aluminium and mounted it on the upper two bell housing bolts. The steel, heater flow pipe exits from the rear of the right hand cylinder head and the return pipe runs in the 'V' under the inlet manifold directly into the rear of the water pump. In the original Mustang, both are neatly positioned to enter the cockpit through the pedal bulkhead to connect to the heater. But in the P4 installation they have to run forward, along the side sill into the cockpit under the dash to the heater outlets.  We have often found it convenient to mount our header tanks at the rear of the engine.

This time I've removed the bottom mounting brackets from our #HTHB tank and fabricated a replacement bracket from 3mm aluminium. and Tig'd it onto the tank. Here's the stock #HTHB (right) and the modified one on the left.

....and here it is mounted under the top two bell housing bolts. I also moved the 15mm tank outlet to the side for better hose routing. You can just see, bottom right in this picture, behind the wiring the right side heater feed outlet in the back of the head.

To improve the hose routing I decided to cut away most of the 15mm diameter steel tube and silver solder a 16mm brass hosetail into the remaining outlet stub. I modified one of our #BJOIN16s, turning off most of one end.

Ready for silver soldering. I have removed the large  'O' ring that seals the part in the head.

It's easier to test for leaks now, before I fit it.

The bits I cut off and the finished version.

 The two, 15mm heater hoses from the engine run along, inside the nearside sill to the forward cockpit panel. I've cut an opening using my mini grinder with a 1mm disc, just the right size alongside the heater connections on the other side of this panel. 

I've known of heater hoses blowing off inside the cockpit and scalding passenger's legs so it's vitally important the minimise number connections inside the cockpit and to make them as secure as possible.

Here are the copper, heater flow and return,  and one of two, tight 180 degree, 15mm silicone hoses that will  pass through the hole in the adjacent cockpit panel and connect, using straight 15mm joiners to the engine hoses on the other side of the panel........

........ using brass 16mm straight joiners - using spring band clips on every joint.

Hence - this big departure for me. I've decided to use our Spring Band Hose Clips on the coolant plumbing in this car. On all my previous builds I've used our NATO spec. stainless hose clips everywhere, but they need to be tightened a few times after the first few runs of the engine. Our self-tightening, Spring Band Clips are the same as Ford originally fitted throughout the engine. So, if you select the correct size and fit them correctly, they should seal well and never need re-tightening.

I'm not sure how much longer this build will take, or even if I'll be around for the engine's first fire-up so I can live with these, no-so-pretty clips.

Here are a couple on the heater feed and header tank, and the clever tool that helps fit them (Our part number #LRHCP).

... and a larger one on the main, lower radiator feed. The correct size to choose is the O.D. of the hose - in this case, 47mm  (Part no: #SBHC47)

This is the custom-made radiator that we had made for our P4s. It proved adequate for all engines from 350 bhp chevys to V12 Ferraris. It sits in chassis brackets and is secured with two aluminium clamps along the top. The two 10 inch fans will be mounted on the back so I had to devise a way to mount the AirCon rad in front. These two, 3mm aluminium brackets will mount it  with enouigh clearance for the fan fixings.

You can see the drier with some unions temporarily fitted and the rad union connections.

Two of our 10 inch electric fans mounted to suck on the rear of the rad should be sufficient for engine cooling and aircon.

A job I've been putting off is remounting the two coil packs. These were originally mounted in the Mustang, on steel brackets that were bolted to the front of each cylinder head. The HT leads were neatly routed from the spark plugs, under covers along the rocker covers and across the top of the alternator.

The problem I have now is that , because the engine is now mounted close to the rear cockpit bulkhead the is no space for the coils in their original position. The picture below shows the left hand coil hanging on the HT leads. There is not enough space to mount the coils using the existing, original HT leads.

I can mount the coils lower down on the engine but I'll need longer leads.

But first I need to make new mounting brackets for the coils and find a new mounting position. I modified one of the original brackets, cutting away all the excess metal leaving the rectangle shown below. I started to make a duplicate one and drill out the centre.

I used a mini angle grinder and my Makita powerfile to cut and dress the hole.

I cut and welded a couple of 'ears' for mounting onto two studs on the front of the engine.

.

The finished mounting plates - powder coated silver.

The silicone HT cables are bonded into dedicated, 7" long rubber plug caps and at the coil end into caps that clip onto the coil outlets. 

But there is another issue. IVA requires the HT leads to be suppressed - which they probably are, and also requires the manufacturers name and identification to be printed on the cable every 120mm along its length. The original leads, although never used, were made in 1998. They may be suppressed but don't otherwise comply with 2024 UK IVA rules so I've measured-up and ordered 10 metres of compliant cable from a company called Ignition Leads Direct. 

Here's the plug end. 

I researched online unsuccessfully to find a supplier of the components so that I could buy some new HT cable and make my own leads so I patiently prodded and poked with small, blunted tools to release the silicone adhesive that sealed the cable into the rubber caps at each end - eventually separating the components. I reckon I can prise open the crimped ends and make a tool to crimp them back onto new cable. 

This should keep the IVA man happy.

Here, I've successfully removed the plug connector from the old HT lead and re-crimped to the new cable with this HT crimping tool

New leads - coil end.

Cylinder I.D. clip on numbers on both ends.