The Imp Site

Hillman Imp and Singer Chamois Conversions

Bred on England's racing circuits by Roger Nathan Racing Limited

Brochure

STAGE 4
FULL RACING SPECIFICATION AS FITTED TO OUR RECORD-BREAKING WORKS IMPS

This conversion has been perfected after five years of research, development and testing on the racing circuits and dynamometer, and is the ultimate in conversions for the lightweight aluminium I:np engine.

All parts are carefully examined before assembly and the necessary parts are erack-tested for faults: this is to ensure maximum reliability. To eliminate vibration and stress at sustained high r.p.m. the flywheel is machined and lightened and together with the crankshaft and special clutch assembly dynamically balanced. These parts are then assembled and again balanced as one unit. Connecting rods and pistons receive the same treatment.

The cylinder head is completely re-worked, ports and port throats are enlarged to maximum permissible dimensions. Conbustion chambers are altered to our own specification and the compression ratio is raised. Maximum size valves are fitted with stronger inner and outer valve springs. Our own type No. 6 camshaft, specially designed for racing, gives maximum power at 8400 r.p.m. and a modified cam carrier is supplied to house the racing camshaft. An aluminium oil cooler adaptor block take-off is fitted between the cylinder block and the oil filter and oil pressure valve unit. The racing distributor supplied with this conversion is specially made for us by Lucas an6 is designed with an advance curve to suit our camshaft. The sump (oil pan) is of our own design of large capacity and is baffled to eliminate surge.

THESE ENGINES ARE EXTREMELY RELIABLE AND STURDY, AND IF THE OCCASION DEMANDS 9,500 R.P.M. CAN BE USED.

Prices:Carrying out conversion to customer's own engine
For prices of new Imp racing engines please see page 5.
£197. 8. 6.
Deposit required:50% with order, the balance being payable on completion. 
Preparation time:3 - 4 weeks. 
Dimensions and weight: Please see page 15. 
RUNNING IN:All engines can be run in and tested on the dynamometer. The charge for this, including petrol and mechanic in attendance, is£32.10. 0.

849 c.c. maximum torque 66.1 lbs.ft. at 5800 r.p.m.  92   b.h.p. at 8000 r.p.m.

875 c.c. maximum torque 69   lhs.ft. at 5500 r.p.m.  94.3 b.h.p. at 8200 r.p.m.

998 c.c. maximum torque 78   lbs.ft. at 5200 r.p.m. 111.5 b.h.p. at 8400 r.p.m.


Postage and packing extra.

4





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File version: 14 Feb 2017
File started: 14 Feb 2017