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Hartwell folder

GRH%, competition no.12 - drawing

Over the years, Hartwell Tuning has become synonymous with 'Speed', 'Racing', and 'Rallies', providing specialist knowledge in the preparation of Rootes Group cars. Now the 'Hartwell Imp' is an established winner which provides the ardent enthusiast, the businessmen or pleasure motorist with a combination of exhilarating performance and added safety.

 

Hartwell Tuning

 

Proprietors: George Hartwell Ltd.

 

Imp and Chamois Tuning Conversions
for the Enthusiast and Competition Driver

 

    Group I    
 
    Group II    
 
   Group III   

Group I tuning requires a minimum of work and provides improved performance which is well worth the expenditure involved.

Efficiency is increased by modifying the cylinder head by matching, with valve throats and ports reshaped and polished. Inlet and exhaust manifolds are shaped and matched to the cylinder head, combustion chambers are polished and the compression ratio is raised; in addition, high rate valve springs are fitted.

The standard carburettor, which is retained, is thoroughly checked and any necessary adjustments effected (this also applies to the ignition system).

To complete the conversion, new sparking plugs are fitted, the oil filter is replaced and the engine oil is renewed.

 
 

Group II tuning includes all the modifications of Group I plus the addition of a tuned length four branch exhaust system, incorporating a high efficiency exhaust box. This group also provides a very lively performance, placing the Imp or Chamois into the sports car field . Effortless acceleration through the gears quickly takes you to a comfortable high cruising speed .

 

This is a degree of tuning which will enable you to win races and rallies, but which is also suitable for day-to-day motoring.

The cylinder head is modified by raising the compression ratio, enlarging, reshaping and polishing the valve throats and ports. Oversize inlet and exhaust valves are operated by the 'Hartwell' special camshaft, utilising high-rate double valve springs. Twin Stromberg CD125 carburettors, suitably jetted and incorporating hand-operated choke control, are mounted on a special 'Hartwell' combined four branch inlet/exhaust manifold . This exhaust system includes a high efficiency silencer.

0-30 mph
5.8 secs.
(6.0)
0-40 mph
8.7 secs.
(9.5)
0-50 mph
13.3 secs.
(14.9)
0-60 mph
19.6 secs.
(22.0)
0-70 mph
30.0 secs.
(35.2)
Maximum mph
84.7
(78.4)
 
0-30 mph
4.1 secs.
(6.0)
0-40 mph
7.0 secs.
(9.5)
0-50 mph
11.1 secs.
(14.9)
0-60 mph
16.2 secs.
(22.0)
0-70 mph
23.9 secs.
(35.2)
Maximum mph
88.0
(78.4)
 
0-30 mph
4.6 secs.
(6.0)
0-40 mph
6.8 secs.
(9.5)
0-50 mph
9.3 secs.
(14.9)
0-60 mph
14.0 secs.
(22.0)
0-70 mph
18.3 secs.
(35.2)
Maximum mph
98.0
(78.4)

 

   Group IV   
 
Auxiliary instrument panel. An attractively designed auxiliary instrument panel is also available. Suitably located alongside the existing instrument nacelle, trimmed in black or matching vynide and accomodating an electronic tachometer, oil pressure and water temperature gauges.
 
auxiliary instrument panel

This is Hartwell Tuning's latest development, providing Fierce acceleration and superior performance. The standard engine size is increased in capacity to 998 c.c. and fitted with competition specification pistons, with the crankshaft and con-rods 'crack tested'. The flywheel is lightened, and the crankshaft, flywheel and clutch are dynamical1ly balanced as an assembly; pistons and conrods are also balanced.

The cylinder head is modified by fitting larger valve inserts to accept oversize valves and valve throats and ports are reshaped and polished; a high lift camshaft and double valve springs are also incorporated. Furthermore, Group IV includes twin Stromberg 150 C.D. carburettors on a special combined inlet-exhaust manifold and a free-flow exhaust box. (Weber carburettors mounted on a special manifold can be supplied as an alternative at extra cost.)

 
Twin Weber carburettors are offered as an optional extra on the Group IV conversion. As shown in the photograph, these carburettors are mounted on a special manifold.
 
Twin Weber carburettors
 
Cylinder head. Increased efficiency is obtained by meticulous attention to detail. The cylinder head is machined, valve throats and ports are reshaped and polished - always adhering to very close tolerances. The prepared head shown here is now ready to 'go to work' on a Hartwell Imp.
 
Hartwell cylinder head
0-30 mph
4.05 secs.
0-40 mph
5.9 secs.
0-50 mph
8.1 secs.
0-60 mph
11.6 secs.
0-70 mph
14.8 secs.
Maximum mph
102.0
 
Twin Stromberg carburettors are fitted to Group III and IV conversions, suitably jetted and incorporating hand choke controls, and mounted on a Hartwell designed four branch inlet/exhaust manifold.
 
twin Stromberg carburettors

 

The basic design of both the Imp and the Chamois, with rear mounted overhead camshaft engines of cast aluminium, makes it a natural for high speed conversions. Over the past two years Hartwell Tuning have developed four stages of tuning for these cars: Groups I, II, III, which are also available in kit form, and Group IV, where it is essential that the conversion is carried out at our works. In addition, the following optional extras are available:

  • Engine oil cooler.
  • Front mounted radiator.
  • Brake servo assistor.
  • Competition type brake linings.
  • Suspension modifications including lowered 'high-rate' road springs, special shock absorbers, front anti-roll bars, etc.
  • Special instrumentation.
  • Lightweight fibreglass body panels and competition seats.
  • Perspex windows
  • Special services offered for body and trim alterations.
  • 'Crack Testing', balancing, etc.

GRH 5 - Hartwell Imp
BHP x rpm - Hartwell conversions

Write today to the Tuning Manager for full details and prices.

Hartwell Tuning

35-41 Holdenhurst Road  .  Bournemouth

Telephone Bournemouth 26566


 


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© Franka
File version: 29 Apr. 2012
File started: 30 Apr. 2012
Folder supplied by R. Human