Episode 16 is what Retropower calls the last episode of its Gordon Murray Mk1 build series. The car is registered through an IVA test, given a full paint correction and ceramic coating, and then mapped on a rolling road to see what the Cosworth engine really makes.
Video: Retropower on YouTube · watch “Gordon Murray's MK1 Escort - Retropower Build Episode 16” on YouTube
What happens in Episode 16
IVA test (0:41). Heavy modification can raise questions about whether a car’s original registration is still valid. So, from the start, Retropower planned to put this one through the IVA (Individual Vehicle Approval) test and re-register it. Preparing for it, including sharp edges and emissions, took about six weeks. It failed on only one item. The speedo sensor sits on a front wheel, which isn’t driven, and the test station had no way to check its calibration. An independent calibration certificate resolved it.
Under the bonnet (2:48). The engine bay is seen complete for the first time: the strut brace, anodised reservoir caps laser-etched with logos, and the plaque Cosworth made. That plaque marks Gordon’s first Grand Prix win and 50 years of the Cosworth DFV.
Paint correction and ceramic coating (4:22). After two years of build work, the paint had picked up fine handling marks. After checking paint depth and stripping the surface with an alcohol wipe, the detailer worked panel by panel. The composite bonnet and boot lid were the hardest to work, at over four hours per panel just for the second stage. In all, it took more than four stages of cut and polish and about 40 hours. A ceramic coating, which the detailer says lasts two to three years, protects the paint.
Northampton Motorsport (8:48). The car goes about 45 minutes away for mapping. The business has long been a Weber and SU dealer. Cosworth develops its engines on an engine dyno, without the car’s real exhaust or airbox. A rolling road tests the engine as installed, including cold starts, idle and part-throttle driving.
How the map is built (14:27). The rollers hold the engine at a set speed while throttle goes from closed to full. Fuel is set using the emissions readout, then ignition for the best power and torque short of detonation, which the tuner listens for through headphones linked to an engine-mounted sensor. Separate maps cover overrun, idle and warm-up.
Results (19:39). The engine made 245hp against Cosworth’s quoted 250. Retropower puts the gap down to the exhaust, which is limited by how tight the Mk1 floor is without a tunnel. Peak torque was about 176lb ft, with around 150lb ft from 3,000rpm,. The only problem was gear oil escaping from the diff breather, fixed for now with a catch pot.
Next (22:16). A wheel alignment check, then road and track testing, ending with Gordon driving the car himself.
Parts, tools and suppliers mentioned
- IVA test, plus an independent speedo calibration certificate
- Paint depth gauge, alcohol strip-down, multi-stage machine polish, ceramic coating
- Northampton Motorsport rolling road, emissions analyser and knock-detection headphones
- Catch pot on the diff breather
Lessons for your own Mk1
- Plan for IVA from day one if the car will be heavily modified; it affects edges, trim and emissions.
- Put the speed sensor somewhere a test station can check it, or have the calibration certified.
- Leave paint correction until the build is finished, because workshop handling marks the paint.
- Map on a rolling road with the real exhaust and intake fitted, and expect most of the time to go on drivability.
Mk1 context
Period performance Mk1s such as the Twin Cam and RS1600 ran twin Weber carburettors, which is why a Weber specialist like Northampton Motorsport is a familiar name in Escort circles. This car keeps the classic look but uses modern engine management, so it can pass today’s emissions rules.
Related
- Series hub: all Retropower Gordon Murray Mk1 episodes
- Previous: Episode 15, Retro Rides debut and first fire-up
- Next: Episode 17, the finished car driven by The Late Brake Show
- Engine background: the Cosworth visit in Episode 5
- Background: the complete history of the Mk1 Ford Escort
- More builds on video: Mk1 Escort build videos