LOTUS CORTINA SPARES CENTRE LTD.
POWERDYNE CAMSHAFTS FOR 1558cc LOTUS TWIN CAM TYPES
The following ASCII text may be saved and printed or editted in virtually any word processor.
POWERDYNE CAMSHAFTS FOR 1558cc LOTUS TWIN CAM TYPES:
'LCS 45' (Sprint)Road 'Sprint' profile. Gives smooth flexible power throughout
whole rev range.
Valve timing 26/66/66/26. Duration 2720. Valve lift .340" (8.64mm)
Installation Data:
Valves clearances (Cold): Inlet .006" (.l5mm)
Exhaust .008" (.l8mm)
Inlet valve fully open 1100 ATDC.
Recommended parts:
New standard tappets should be fitted. If fitting used tappets these should be
thoroughly checked and re lapped.
8 valve springs LCS 95
'LCS 47' Good fast road cam. Similar power to the '46' but not so
tractable in the lower rev. range. However, can normally be fitted without
carrying out any further modifications.
Valve timing 46/70/70/46. Duration 2960. Valve lift .345" (8.76mm)
Installation Data:
Valve clearances (Cold): Inlet .007" (.l8mm)
Exhaust .008" (.2Omm)
Inlet valve fully open 1020 ATDC.
Recommended parts:
New standard tappets should be fitted. If fitting used tappets these should be
thoroughly checked and re lapped.
8 valve springs LCS 97.
'LCS 46' Fast road/rally cam. Very tractable at low revs with good power
between 2000 and 7000 rpm.
Valve timing 34/66/66/34. Duration 2800. Valve lift .410" (10.41 mm)
Installation Data:
Valve clearance (Cold): Inlet .008" (.2Omm)
Exhaust .009" (.23mm)
Inlet valve fully open 1060 ATDC.
Apart from some large valve 'Sprint' type cylinder heads it will be necessary
to deepen the valve spring seat location. This measurement should be
2.125"/2.130" (53.98/54.lOmm) from centre line of camshaft to spring seat
location. It may also be necessary to relieve the bottom of the tappet guide
bores to allow adequate tappet travel.
To check piston/valve contact ensure there is a minimum clearance of 0.160"
(4.O6mm) between valve head and piston at TDC.
'LCS 48' Very popular rally/race type camshaft. Best power band between
4500 and 7500 rpm.
Valve timing 46/78/70/50. Duration 3040. Valve lift .410" (10.41 mm)
Installation Data:
Valve clearances (Cold): Inlet .007" (.l8mm)
Exhaust .008" (.2Omm)
Inlet valve fully open 1060 ATDC.
Apart from some large valve Sprint type cylinder heads it will be necessary to
deepen the valve spring seat location. This measurement should be
2.125"/2.130" (53.98/54.lOmm) from centre line of camshaft to spring seat
location. It may also be necessary to relieve the bottom of the tappet guide
bores to allow adequate clearance for tappet travel. To check piston/valve
contact ensure there is a minimum clearance of .200" (Smm) between valve
head and piston at TDC.
'LCS 49' Similar to '48' but slightly higher lift giving the LCS 49 a
marginal increase in power and rev range.
Valve timing 50/74/74/50. Duration 3040, Valve lift .420" (10.67mm)
Installation Data:
Valve clearances (Cold): Inlet .008" (.2Omm)
Exhaust .009' (.23mm)
Inlet valve fully open 1020 ATDC.
Cylinder head modifications as per 'LCS 48' specification above.
To check piston/valve contact ensure there is a minimum clearance of .225"
(5.7Omm) between valve head and piston at ATDC.
Recommended parts for use in conjunction with performance camshafts reference
'LCS 46', 'LCS 48' and 'LCS 49':
8 - LCS 50 tappets
8 - LCS 52 steel tappets (competition use)
8 - LCS 96 H/Duty V/Springs
8 - LCS 97 Comp. V/Springs (Use for competition)
8 - LCS 100 Retainers (for increasing V/Spring fitted length)
The following is a brief listing of alternative profiles suitable for serious
competition use only. In most cases extensive cylinder head modification
work is required.
58/82/82/58 Lift .410"
56/88/80/64 Lift .440"
57/87/87/57 Lift .440"
(BRM)
60/90/86/62 Lift .490" (IN) .470" (EX)
(Hart formula B)
IMPORTANT NOTES:
Thoroughly clean all parts and wipe a liberal coating of cam lube on all cam
and tappet surfaces. Check cam bearings for wear and pitting.
Replace if necessary.
Read the fitting instructions carefully and carry out all the relevant
installation checks. All stripping and re assembly work must be carried out
as per the procedures laid down in the relevant workshop manual.
Our guidance notes and data are only additional to this information and
must not be used as a substitute.
Tappet adjustment shims are available as follows:
'Biscuit' type Ref LCS 53 - Range .060" to .150" (1.52mm to 3.81 mm)
'Top hat' type Ref LCS 54 - .200" (approx) - 5.O8mm
For accurate adjustment of cam timing an offset dowel kit is available
under Ref LCS 60.
The foregoing is a selection of the more popular cams for the Lotus twin cam
engine. Our camshaft department can offer additional profiles to suit
individual requests.
For further information and advice
please ring 01460 73775 (Technical Service Dept).
ORIGINAL EQUIPMENT SPECIFICATION & DATA:
Camshaft end float .002" - .008" (.051 mm - .203mm)
Camshaft journal dia. 1 .000"/1 .0005"
Camshaft housing dia. 1.1 255"/1 .126"
Tappet diameter/length 1 .375"/.875"
Cyl. head torques 60/65 lb/ft (10 off)
Cyl. head torque 18/20 lb/ft (1 off)
Cam bearing cap torque 15/20 lb/ft.
Cam cover torque 8/10 lb/ft.
