Tip of the Pits

My 20+ years of experience as a car constructor and competitor, plus the expertise of our specialist technicians at GGR, is now available to you in a series of tips that we will regularly update, allowing you to advance your knowledge along with us.
This issue of Tip of the Pits is simply a listing of basic technical information to aid you as you work on your Cosworth.

Have Fun !
Graham.

Remember, the Golden Rule is,
"If you do not have the right equipment or experience, save yourself money and heartache and entrust the work to someone who does."

TIGHTENING TORQUES
Remember it is as important to ensure that bolts are not over tightened as under tightened.
Nm lb/ft

OIL DRAIN BUNG INTO SUMP 21-27 16-20
ALTERNATOR TO MOUNTING BRACKET 18-25 14-19
ADJUSTMENT STRAP TO ALTERNATOR 18-25 14-19
ALTERNATOR STRAP TO WATER PUMP 18-25 14-19
TIMING BELT COVER(ALL BOLTS) 8-10 6-8
SECONDARY TO PRIMARY EXHAUST MANIFOLD(2WD) 32-36 24-27
TURBOCHARGER TO MANIFOLD 40-48 30-36
CAM CAP TO CYLINDER HEAD(M6) 8-10 6-8
CAM CAP TO CYLINDER HEAD(M8) 12-23 9-17
CAM PULLEY TO CAMSHAFT 59-63 44-47
CAMBELT TENSIONER RETAINING NUT 40-48 30-36
CRANKSHAFT PULLEY TO CRANKSHAFT 122-135 92-101
CAM COVER BOLTS 10-15 8-11
CYLINDER HEAD(STRETCH BOLTS)
STAGE 1
STAGE 2
STAGE 3
STAGE 4

20-25
45-50
+90deg
+90deg
15-19
34-38

CHECK TORQUE(IF BOLTS TURN-REPLACE THEM) 110 83
SPARK PLUG TO CYLINDER HEAD(LUBRICATE THREADS) 28-33 21-25
WHEEL NUTS 100 75

OIL PRESSURE (ALL MODELS)
MINIMUM OIL PRESSURE WHEN AT NORMAL OPERATING TEMPERATURE.
IDLE SPEED 1.8 BAR (26 PSI)
2000 RPM 2.4 BAR (35 PSI)

FUEL PRESSURE (ALL MODELS)
IDLE SPEED 3.0 BAR (44 PSI)
WITH PRESSURE PIPE REMOVED FROM REGULATOR 3.5 BAR (51 PSI)

SPARK PLUGS
There is a huge range of spark plugs that can be fitted to the Cosworth engine. Based on our experience, here are our recommendations:
TYPE USE ELECTRODE GAP
MOTORCRAFT AGPR 12PP STANDARD SMALL TURBO ESCORT 1.1 - 1.2mm (0.044" - 0.048")

MODIFIED SMALL TURBO ESCORT 0.86 - 0.9mm (0.034" - 0.036")

MOTORCRAFT AGPR 12 PP8 (AS ABOVE BUT 0.8mm GAP STANDARD) STANDARD LARGE TURBO ESCORT 1.1 - 1.2mm (0.044" - 0.048")

STANDARD SIERRA COSWORTH 0.7 - 0.8mm (0.028" - 0.032")
MODIFIED COSWORTH SIERRA OR ESCORT (MAX. BOOST 1.6 BAR) 0.7 - 0.8mm (0.028" - 0.032")

MOTORCRAFT AGPR 902 P (COOLER RUNNING THAN AGPR 12 PP8) MODIFIED COSWORTH SIERRA OR ESCORT (MAX. BOOST 2.0 BAR) 0.6 - 0.7mm (0.024" - 0.028")

CHAMPION C 59 C COMPETITION OR TRACK DAY COSWORTH (BOOST PRESSURE DEPENDANT) 0,5 - 0.7mm (0.020" - 0.028")

CHAMPION C 57 C AS ABOVE BUT FOR HARDER WORKING CONDITIONS (COOLER RUNNING PLUG) AS ABOVE

TYRE PRESSURES
FRONT REAR USE

SIERRA COSWORTH
205/50 VR 15 2.1 BAR(31 PSI) 2.3 BAR(34 PSI) Normal load & speed
2.3 BAR(34 PSI) 2.5 BAR(37 PSI) Heavy load, Normal speed
205/50 VR 15 2.3 BAR(34 PSI) 2.5 BAR(37 PSI) Normal load, High speed
2.6 BAR(38 PSI) 3.0 BAR(44 PSI) Heavy load, High speed
ESCORT COSWORTH
225/45 ZR 16 2.0 BAR(29 PSI) 2.2 BAR(32 PSI) Normal load & speed
2.2 BAR(32 PSI) 2.4 BAR(35 PSI) Heavy load, Normal speed
2.2 BAR(32 PSI) 2.4 BAR(35 PSI) Normal load, High speed
2.5 BAR(37 PSI) 2.9 BAR(43 PSI) Heavy load, High speed
T125/80 R16 97M Emergency spare tyre - 4.2 BAR (62 PSI)

PLEASE NOTE THAT AS A GENERAL RULE, INCREASES IN WHEEL DIAMETER REQUIRE A SMALL INCREASE IN PRESSURE [1 BAR (1.5 PSI) PER INCH], AND INCREASES IN TYRE WIDTH MAY REQUIRE A SMALL DECREASE IN PRESSURE.

LUBRICATION RECOMMENDATIONS
GEARBOX(2WD) AUTOMATIC TRANSMISSION FLUID 2.55 LTRS(0-5mm BELOW PLUG)
GEARBOX(4x4) DEDICATED MT75 TRANSMISSION OIL (SIMILAR TO AUTO TRANSMISSION OIL) 1.2 LTRS(0-5mm BELOW PLUG)
TRANSFER BOX(4x4) DEXTRON TYPE AUTO TRANSMISSION 0.5 LTRS(18mm BELOW PLUG)
ENGINE OIL FULLY SYNTHETIC ENGINE OIL 5W/40 OR 15W/50 NOMINAL CAPACITY 4 LTRS(3-6mm BELOW TOP MARK ON DIPSTICK)
DIFFERENTIAL OIL 75/90W SEMI/FULLY SYNTHETIC NOMINAL CAPACITY 1 LITRE (0- 5mm BELOW PLUG)

BRAKE DISC DETAILS

DIAMETER ORIGINAL THICKNESS MINIMUM THICKNESS
2 WHEEL DRIVE FRONT 283mm 24.15mm 22.8mm
2 WHEEL DRIVE REAR 273mm 10.3mm 8.9mm
4 WHEEL FRONT 278mm 24.15mm 22.8mm
4 WHEEL REAR 273mm 20.00mm 18.0mm
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Correspondence/Requests
Sales Enquiries: sales@grahamgoode.com
Technical Enquiries: tech@grahamgoode.com
Tel: (+44) 0116 244 0080
Fax: (+44) 0116 244 0140

	Nm	lb/ft
OIL DRAIN BUNG INTO SUMP	21-27	16-20
ALTERNATOR TO MOUNTING BRACKET	18-25	14-19
ADJUSTMENT STRAP TO ALTERNATOR	18-25	14-19
ALTERNATOR STRAP TO WATER PUMP	18-25	14-19
TIMING BELT COVER(ALL BOLTS)	8-10	6-8
SECONDARY TO PRIMARY EXHAUST MANIFOLD(2WD)	32-36	24-27
TURBOCHARGER TO MANIFOLD	40-48	30-36
CAM CAP TO CYLINDER HEAD(M6)	8-10	6-8
CAM CAP TO CYLINDER HEAD(M8)	12-23	9-17
CAM PULLEY TO CAMSHAFT	59-63	44-47
CAMBELT TENSIONER RETAINING NUT	40-48	30-36
CRANKSHAFT PULLEY TO CRANKSHAFT	122-135	92-101
CAM COVER BOLTS	10-15	8-11
CYLINDER HEAD(STRETCH BOLTS) STAGE 1 STAGE 2 STAGE 3 STAGE 4	20-25 45-50 +90deg +90deg	15-19 34-38
CHECK TORQUE(IF BOLTS TURN-REPLACE THEM)	110	83
SPARK PLUG TO CYLINDER HEAD(LUBRICATE THREADS)	28-33	21-25
WHEEL NUTS	100	75

IDLE SPEED	3.0 BAR (44 PSI)
WITH PRESSURE PIPE REMOVED FROM REGULATOR 3.5 BAR (51 PSI)

TYPE	USE	ELECTRODE GAP
MOTORCRAFT AGPR 12PP	STANDARD SMALL TURBO ESCORT	1.1 - 1.2mm (0.044" - 0.048")
MOTORCRAFT AGPR 12PP	MODIFIED SMALL TURBO ESCORT	0.86 - 0.9mm (0.034" - 0.036")
MOTORCRAFT AGPR 12 PP8 (AS ABOVE BUT 0.8mm GAP STANDARD)	STANDARD LARGE TURBO ESCORT	1.1 - 1.2mm (0.044" - 0.048")
	STANDARD SIERRA COSWORTH	0.7 - 0.8mm (0.028" - 0.032")
	MODIFIED COSWORTH SIERRA OR ESCORT (MAX. BOOST 1.6 BAR)	0.7 - 0.8mm (0.028" - 0.032")
MOTORCRAFT AGPR 902 P (COOLER RUNNING THAN AGPR 12 PP8)	MODIFIED COSWORTH SIERRA OR ESCORT (MAX. BOOST 2.0 BAR)	0.6 - 0.7mm (0.024" - 0.028")
CHAMPION C 59 C	COMPETITION OR TRACK DAY COSWORTH (BOOST PRESSURE DEPENDANT)	0,5 - 0.7mm (0.020" - 0.028")
CHAMPION C 57 C	AS ABOVE BUT FOR HARDER WORKING CONDITIONS (COOLER RUNNING PLUG)	AS ABOVE

	FRONT	REAR	USE
SIERRA COSWORTH
205/50 VR 15	2.1 BAR(31 PSI)	2.3 BAR(34 PSI)	Normal load & speed
	2.3 BAR(34 PSI)	2.5 BAR(37 PSI)	Heavy load, Normal speed
205/50 VR 15	2.3 BAR(34 PSI)	2.5 BAR(37 PSI)	Normal load, High speed
	2.6 BAR(38 PSI)	3.0 BAR(44 PSI)	Heavy load, High speed
ESCORT COSWORTH
225/45 ZR 16	2.0 BAR(29 PSI)	2.2 BAR(32 PSI)	Normal load & speed
	2.2 BAR(32 PSI)	2.4 BAR(35 PSI)	Heavy load, Normal speed
	2.2 BAR(32 PSI)	2.4 BAR(35 PSI)	Normal load, High speed
	2.5 BAR(37 PSI)	2.9 BAR(43 PSI)	Heavy load, High speed

GEARBOX(2WD)	AUTOMATIC TRANSMISSION FLUID	2.55 LTRS(0-5mm BELOW PLUG)
GEARBOX(4x4)	DEDICATED MT75 TRANSMISSION OIL (SIMILAR TO AUTO TRANSMISSION OIL)	1.2 LTRS(0-5mm BELOW PLUG)
TRANSFER BOX(4x4)	DEXTRON TYPE AUTO TRANSMISSION	0.5 LTRS(18mm BELOW PLUG)
ENGINE OIL	FULLY SYNTHETIC ENGINE OIL 5W/40 OR 15W/50	NOMINAL CAPACITY 4 LTRS(3-6mm BELOW TOP MARK ON DIPSTICK)
DIFFERENTIAL OIL	75/90W SEMI/FULLY SYNTHETIC	NOMINAL CAPACITY 1 LITRE (0- 5mm BELOW PLUG)

	DIAMETER	ORIGINAL THICKNESS	MINIMUM THICKNESS
2 WHEEL DRIVE FRONT	283mm	24.15mm	22.8mm
2 WHEEL DRIVE REAR	273mm	10.3mm	8.9mm
4 WHEEL FRONT	278mm	24.15mm	22.8mm
4 WHEEL REAR	273mm	20.00mm	18.0mm

GGR Home
Correspondence/Requests Sales Enquiries: sales@grahamgoode.com Technical Enquiries: tech@grahamgoode.com Tel: (+44) 0116 244 0080 Fax: (+44) 0116 244 0140