This Section Is About All Things Heating & Cooling
Fitting the radiator was quite straightforward but a bit fiddly. It came with 4 x 3.2 mm rivets for fixing to the single hole at each end of the support frame, but not having a 3.2 mm drill bit, I changed them to 4 mm (I tried a 3 mm hole on a piece of scrap ali' and it wasn't happening, and I wasn't going to force it.
Fixed the fan on the rails (4 x M6 nuts) and placed the whole lot on the radiator and marked it up for drilling and riveting. Point of caution here. The bottom water rail is quite close to the radiator frame so I couldn't mess this up. Made a 2 mm pilot hole first then drilled out to 4 mm to complete the support frame upgrade. I also used a bench drill stand when drilling to ensure vertical holes and, most importantly, to ensure nothing grabbed.
The fan is a 16 inch curved-blade beast of a thing and is [factory] configured to "push" the air. Not concerned about this at the moment as it is only one centre bolt to change the fan around to make it "pull" the air. I've mounted the fan on the back of the radiator so it needs to pull the air through; and as it's an induction fan (and as I don't know which way it's going to turn,) I could probably just reverse the polarity of the motor if needed, but I'll have to see what's really happening before I consider this option.
Looking at the lower mounting plates, I decided to stick on 2 mm thick rubber insulation pads. I then put some rubber tube over the two top pegs, as lateral insulation was required... So far so good.
Took the fan off to mount the radiator in the chassis and put a cardboard protector over the front matrix to protect that. Also, as I have the body-shell on the chassis, I took off the two front cross-member bars to make more room to manoeuvre the radiator. I also loosened the radiator top frame to make more vertical room. A very generous hour later, job done... Except, I have to shorten a couple of bolts for the lower fixings. Am not comfortable with bolting into the radiator without precisely knowing how far the lower water rail is from the bottom. There is 5 mm of thread on the radiator fixing hole, and I have to allow for the chassis frame mounting plate and a bit of squishing of the rubber pads...
Measured and cut the lower radiator retaining bolts to 1.5 cm. This is the correct length for the bottom holes of the radiator. Any longer and the bolts would be touching the bottom cooling core-tube... This would not be good!
Heating & Cooling - The Plumbing
- Hose Type: Did my usual ‘subject’ research and discovered there are silicone hoses and there are 'silicone hoses.' And I did learn that the composition and strength of a silicone hose could be less than expected. My conclusion being, it's definitely not worth the risk of getting them online from some far-off land.
- Clamps: Went for the Viper Performance stainless steel 20 mm wide band T-Bolt clamps and their Mikalor worm-drive 12 mm wide band clamps. Silicone [apparently] has a tendency to become quite pliable when hot, and a high-pressure hot water blow-out is not on my list of things to experience. I used the 12 mm worm-drive clamps on the heater hoses as they are less chunky and therefore look better i.e. more proportionate on the smaller hoses (in my humble opinion.)
- Hose Joiners: I wanted some aluminium tubing showing along some hose runs. This, not only to have a bit of functional bling but to also cut down on the number of clamps. E.g. a 90O hose will need four clamps, whereas a 90O aluminium bend will only need two. I also realised it is very important for all joiners to have a bead or a decent flare at each end. And in this theme I had a major issue sourcing what I wanted, so I made my own... More on this later.
Header Tank: Mounting the header tank on the engine-bay cross-member was a self-induced conundrum. And, as I'm not a fan of rivnutting into steel tubes that support things, I bought some Staumph pressure clamps. These were perfect for this kind of job. However, having fitted everything in place I only had ~2 mm clearance between the radiator cap and the underside of the bonnet; and one of the clamps was very very close to the front of the water pump... Not good. So it was over to plan "B", and that was to tap a couple of M5's directly into the top of the cross-member for a direct fix... I'll use the clamps to mount the front number plate.
- Thermostat/Header Tank Connecting Pipe: This is a 90O, 38 mm x 10 cm leg hose. Trimmed the vertical leg to line things up with the horizontal intake on the header tank.
- Intake Manifold/Water Pump Drainback Pipe: This is a 90O, 19 mm to 16 mm reducer connecting the intake manifold to the water pump. Each leg was cut down to 5.5 cm for a perfect fit.
- Radiator (Bottom Outlet): I used 38 mm spring-reinforced pipe for this. Expensive piece of kit but well worth it as I don't want this hose creasing or kinking or collapsing when hot.
- Radiator (Top Inlet): This connects the lower outlet pipe on the header tank to the top inlet on the rad’. I used spring-reinforced pipe type for this too... I had enough over from the lower pipe run. A one-metre length is more than enough for both of these jobs.
- Water Pump Inlet: The inlet to the pump is 45 mm so I needed a 90O, 45 to 38 mm reducer... Or is that a 38 to 45 mm expander?
Radiator Cap: I fitted a 15lb psi cap as per my engine documentation instruction. I did look into this, and although a higher psi cap is good for preventing overheating, a lower pressure cap is good for not blowing pipes off. I have a whopping 16-inch fan that will take care of the temperature so a 15lb psi cap is good enough for my Ford 302. However, it seems that a 20lb cap is common on T70's.
Heater Pipes: This seemingly simple task of running a few hoses around the block turned out to be one of the most challenging jobs [so far] on the whole build. I wanted the pipes to blend and not look out of place, and most importantly I wanted a heater valve which operated via an old-fashioned Bakelite type 'pull-push' knob... More on this later.
Background Information on Water Flow: The piping-up of the under-wheel arch heat exchanger required the top water-outlet on the intake manifold to be connected to the lower inlet pipe on the heat exchanger, and the top outlet pipe on the heat exchanger to be connected to the ‘return’ inlet port on the water pump. The reason for this is, the water pump i.e. the return inlet port, is 'suction'; so when the water pump is rotating water flows out from the top outlet of the intake manifold and feeds the lower inlet pipe on the heat exchanger; then the water flows up through the exchanger and out of the top outlet pipe and back to the lower water pump inlet port.
This configuration is necessary because; as bubbles and heat rise, any air in the system will percolate upwards with the natural flow of the water and flushed out of the system. Connect things up the other way and any air has to be forced down through the heat exchanger by the flow of the water... i.e. against gravity... Not good.
Heater Pipe Installation: I started the pipe installation from the heat exchanger by attaching a 90O then a 60O pipe to the bottom outlet, and a 60O pipe to the top outlet. Then it was around the back of the engine bay via a couple of 60O pipes and 90O aluminium bends to the inlet and outlet ports on the intake manifold and water pump. All this with the inclusion of the heater valve.
Heater Valve: I wanted to mount the valve somewhere that didn't cause the control cable to have too many tight turns, and I wanted the valve to be visible, so my [final] final decision was to mount it on a plate adjacent to the heat exchanger outlets. This, to keep things neat and not have pipes cluttering up the place and running everywhere.
First, I lined everything up and made a cardboard template for the mounting plate. Then I spent the rest of the day making it out of a piece of 2 mm mild sheet steel. No easy way to do this, just hack-sawing, bending, Dremelling, drilling and hand-filing. And when I’d finished, I bolted the valve temporarily onto the plate and temporarily fixed it to the engine bay sidewall with self-tappers. I will be using bolts -but not yet. I will need to take it off for painting.
The heater pipes supporting post was made from an old Black & Decker jigsaw ‘T-square' shaped guide [that's the jigsaw attachment that no one ever uses.] I reshaped and adjusted it to support the hoses at the back of the engine bay. This was bolted to the engine block by the re-utilisation of a very well situated surplus-to-requirement bolt hole. A couple of 16 mm 'P' clips were used to attach the pipes to the supporting post.
Straight Hose Joiners: I needed some straight joiners ~5 and 7 cm long; and did buy some from a [supposedly] reputable company but when I received them they were utter rubbish, so they went straight back... I really was not impressed, so I decided to make my own.
For this, I used a standard 15 mm copper pipe and Yorkshire straight-coupling connectors which I soldered (after cutting in half) to the ends of the bespoke sized pipes. The straight-couplings providing the extra 1 mm diameter (16 mm being the diameter of the pipes) and the end beading an extra 1 mm, making a healthy ridge which is perfect for a tight seal.
Painted the valve bracket and pipe-supporting post black to match the engine bay then lined up and tightened everything up.
Filled up with 11 litres (50:50) of water and Halfords antifreeze, and I was pleasantly surprised to find I only had to tweak-up only one clamp.
This part of my build took absolutely ages to do, primarily because I needed to be sure about how it all was to function and look… and I have to admit, I'm quite pleased with the result.