Ford Escort RS1800 Category 3.
Homologation papers no 1605. 650.

BDG. 90mm + 60 maximum bore size. 77.62mm Stroke.

5.230″ (13.2842mm) Connecting rod length.

Only “I” section connecting rods are permitted.

Inlet Valves 1.530″ between centres.
Three or Four bolt exhaust manifold to cylinder head fixings.
The Engine may be mounted direct to the chassis rails.
The water pump may be driven by the flank of the camshaft drive belt.

Fuel system
Carburetors or Mechanical fuel injection.
Kugelfischer Pump Type PL044 fuel injection system is permitted.

Lucas or Lumenition. The Lucas constant energy system is available from John Wilcox Engineering (01455230576)
The Lumenition system uses an Optronic Trigger system and is an alternative to the Lucas system. It is good to 13000RPM! Both systems ignition pack and coil must be mounted on the inner wing. Lucas or Bosch distributors are permitted.


12 or 24V Starter motor circuit. Alternator on Poli V or normal V profile drive belt.


Four speed 2000E or Rocket gearboxes are permitted.

An Alloy casing for 4 speed gearboxes are permitted.

The ZF S5-18/3 is the only 5 speed gearbox permitted.

Dog engagement gearboxes are not permitted.
Concentric Slave cylinders are not permitted.

Front Suspension

Large or Small adjustable platform strut assemblies.
Top Suspension mountings must be rubber bushed. Spherical bearings are allowed.
Rose jointed adjustable lower arms. These must not be able to be adjusted when fitted on the car.
Compression strut tie bars are allowed as is rose jointed anti/roll bars.

Rear Suspension

Slipper springs, Long links, Panhard rod or Watts linkage.
The fitting of Coil over springs is allowed, however as in period a leaf spring must also be fitted.
The Ford works team I am lead to believe used a plastic look alike spring to satisfy the rules.
Three piece solid halfshafts.

Front Brakes

Girling or AP  racing Forest or Tarmac  Alloy 4 pot calipers and discs.
AP Racing CP2361 (Forestry) or CP2270 (Monte Carlo) front brake calipers.

Rear Brakes

Single or dual AP racing rear brake caliper with suitable handbrake modifications. Solid or vented rear brake discs.
AP racing have reproduced the CP2382 rear vented disc brake caliper or CP2383 for solid brake discs. However two CP2577 calipers, one for foot brake and one for handbrake are acceptable. Ian Rix engineering (01379854387) are marketing a modified CP2577 caliper with a built in mechanical handbrake mechanism to satisfy the MOT/road traffic act.

Master Cylinders.

Single outlet master cylinders may be replaced by a Tandem or Twin cylinder arrangement.

The fitting of a dual master cylinder or any other type of device providing a simultaneous action on all four wheels and divided action on two wheels is permitted, providing the original brake pedal and pivot point are used.

The remote brake bias adjuster must be positioned so that it cannot be adjusted by either the driver or co-driver when normally seated in the car.

Wheels and Tyres

13” or 15” diameter rims.
Wheels and tyre size as per MSUK Blue book.

Body Shell

The Centre tunnel may be enlarged at the front bulkhead area to assist gearbox removal.
We have received documented evidence to prove that Ford included an exhaust tunnel for the Grp 4 RS1800.  This recessing is to a maximium of 2 inches.
See drawing below.
The rear wheel arched may be enlarged to accomodate the fitment of 15″ wheels.


Bodywork and arches must remain as shown on the Homologation papers
Composite rear and side windows are permitted.
Fibreglass bonnet and bootlids are allowed.
Alloy body panels are not permitted other than wheel arch extensions.
The bonnet must be plain with no louvres or vents fitted to it.
Front and rear steel bumpers must be fitted.
Heated Front windscreens are permitted.
Digital display dashes are not permitted.