Episode 12 of Retropower’s Gordon Murray Mk1 build finds the car in the assembly workshop as a rolling shell, with the engine and gearbox fitted. The team now takes on the custom engineering jobs the dry build didn’t need.
Video: Retropower on YouTube · watch “Gordon Murray's Mk1 Escort - Retropower Build Episode 12” on YouTube
What happens in Episode 12
Why the delay (1:42). A test build with Nitron’s bare-steel dummy struts found a problem with the fronts, so they went back for a revision. That pushed filming past Christmas.
Engine bay tanks (2:40). Fabricated aluminium tanks in the back corners of the bay hold the brake and clutch fluid and the screenwash. The unions underneath and a welded boss are the only mounts, so no fasteners show and the tanks seem to float. They’ll be clear anodised.
Bonnet release (4:08). The team kept the early cars’ push button in the grille, but machined a new one shaped exactly like a grille slat.
The engine (5:26). The Cosworth engine, with its carbon airbox and trumpets, went into the shell from below on the front subframe. Jobs that would be hard to reach later were done first, such as an anodised aluminium heater pipe running to the back of the head.
Clutch and gearbox (8:13). On a clutch specialist’s advice, they chose a sprung organic plate with an uprated billet pressure plate, on a billet flywheel made by TTV. The mock-up used a second-hand Mazda MX-5 gearbox. The car now has a new one from Mazda.
The gear lever (9:14). On the final cranked lever, the original rubber isolator twisted by about an inch at each end of the gate. The team replaced that section with a sliding sleeve and a push-down reverse lockout. It took about two days.
Rear end (11:35). The steel parts are blasted, zinc sprayed and powder coated. The diff is a scrapyard Sierra unit rebuilt by Quaife with its automatic torque-biasing diff and a 3.6:1 final drive. Each link has a polyurethane bush at one end and a rose joint at the other. The rose joints have no boots, because Retropower finds boots trap water and grit.
Toe and camber (14:07). A reverse-thread link between two lock nuts sets the toe on the car, and an eccentric puck sets the camber. A two-piece propshaft with a centre bearing is being made.
Front end (16:47). The steering rack and track rods were repainted in tough polyurethane. A solid compression strut, instead of the anti-roll bar, locates each lower arm fore and aft, so the wheels stay put under heavy braking.
Hours and what’s next (19:19). The dry sump tank and screenwash parts come next. Retropower estimates the car has had about one person on it full time for a year.
Parts, tools and suppliers mentioned
- Cosworth engine with carbon airbox and trumpets; anodised aluminium heater pipe
- Mazda MX-5 gearbox; billet flywheel by TTV; sprung organic clutch plate with an uprated billet pressure plate
- Quaife automatic torque-biasing diff in a Sierra casing, 3.6:1 final drive
- Nitron struts with remote reservoirs; Ford Sierra rear calipers
- Polyurethane bushes and rose joints; zinc spray plus powder coat; polyurethane paint on the rack and track rods
Lessons for your own Mk1
- Do the hard-to-reach jobs before the engine goes in, like heater and coolant pipes.
- Test-fit any change to the gear lever. A longer or cranked lever adds leverage on the rubber isolator.
- Think twice about rose joint boots. Retropower finds they hold water and grit against the joint.
- Make toe adjustable on the car with a reverse-thread link and lock nuts.
- Don’t rely on the anti-roll bar for fore-and-aft location if you want stable steering under hard braking.
Mk1 context
On a standard Mk1 Escort, the front anti-roll bar also locates the lower arm fore and aft. The bar has to flex, so the wheels move back under braking. Motorsport Escorts commonly use separate compression struts instead.
Related
- Series hub: all Retropower Gordon Murray Mk1 episodes
- Suspension background: Mk1 Escort rally preparation – front suspension & handling and rear suspension
- Background: the complete history of the Mk1 Ford Escort
- More builds on video: Mk1 Escort build videos