Modifying and Tuning Fiat Lancia Twincam Engines – Guy Croft

Modifying and Tuning Fiat/Lancia Twin-Cam Engines. Workshop Manual. Through the pages of this exhaustively detailed manual of engine modification, preparation and tuning, G.C. has made available his years of experience atthe sharp end of engine development to all users of Italy most famous and versatile production engine. G. provides a clear and detailed explanation of the fundamentals of high-performance engine tuning. Invaluable to anyone seeking the ultimate from their car, whatever the source of its engine.


Many years have passed since the forest and tarmac stages of the World Rally Championship echoed to the sound of the Fiat-Abarth 124 and 131 Twin Cams, but such was the success generated by these early cars, in which so many famous drivers made their name, that right up until the official withdrawal of Lancia from the series at the end of 1992, derivatives of those outstanding powerplants were still in use by the works teams. Importantly – as far as we are concerned – this heritage, spanning over two decades, continues to generate enormous interest among motorsport enthusiasts seeking a competitive engine for their clubman car.

This book is not about Abarth; for all their greatness, much of what they did was kept to themselves – perhaps understandably – so little information has ever appeared in print. Life would have been much easier if it had, and of course it would have made fascinating reading! Nearly all the techniques described in this book, therefore, have had to be derived from scratch.

The philosophy behind the work at Guy Croft Tuning over the last nine years has been quite simple – design the parts, test them thoroughly, then make them readily available at an affordable price. A great deal of hard work has gone into extracting the full potential from this remarkable series of engines, and despite the inevitable heartaches along the way, the progress made in establishing the TC. as such a formidable and versatile high-performance powerplant has been a reward in itself. We hope that the work at GCT has made a genuine contribution to the recent resurgence of interest in these unique engines and to their popularity amongst both clubman competitors and high-performance road car enthusiasts.

To work in this field is particularly enjoyable. Fiat and Lancia Twin-Cam owners seem to share a common fascination for the intricate technicalities of special tuning; an increasing number of them have asked me: “Can you supply the parts if I build it myself?” My answer has always been “Yes”, of course, but the purchase has so often been followed by in-depth, extensive telephone queries relating to the build-up and settings! It was in response to this that, two years ago, I discussed the possibility of this book with publisher John Blunsdcn, of Motor Racing Publications. John had been pleased with the success of Fiat and Lamia Twin-Cams, written by my friend Phil Ward, and to which 1 had contributed a chapter on special tuning; if there was a criticism, I was told by some readers, it was that ‘my’ chapter was not big enough.

My broad strategy has been to explain to the reader where to source a suitable engine, how to inspect and prepare it for road and competition use, and how to develop an integrated ‘package’ to eliminate running problems as far as possible in order that their precious budget is not wasted on an uncompetitive or unreliable engine. All the methods described are those actually used at GCT and are tried and tested. I hope readers will find of interest the technical justifications for the practical tuning methods described and will be suitably impressed by the section on owners’ cars, the extent of which offers a clear indication of the wide variety of uses to which the TC can be put.


  • Twin Cam models Tuning theory Tools
  • Stripping and inspecting
  • Cylinder head preparation
  • Camshafts and valve train
  • Block preparation
  • Flywheel, crank and rod preparation
  • Pistons and rings
  • Fuel systems
  • Ignition systems
  • Forced induction
  • Lubrication and cooling
  • Building up the engine
  • Exhaust systems
  • Testing
  • Clutches and gearboxes
  • Owners’ cars
  • Suggested component life schedule/replacement guidelines (competition engines)
  • Initial start-up (all engines)
  • Engine trackside diagnosis for sudden power loss
  • Hints on rolling-road tuning
  • Typical engine specification sheet
  • Useful contacts

Language: English
File: PDF
Pages: 258

Modifying and Tuning Fiat Lancia Twincam Engines – Guy Croft