Tuning Standard Triumphs Over 1300 Cc, by David Vizard

1 2 TUNING STANDARD TRIUMPHS OVER 1300 cc David Vizard PEED S PORT MOTOBOOKS 3 FIRST IMPRESSION FEBRUARY 1970 85113-029-1 Printed and Published by SPEED AND SPORTS PUBLICATIONS LTD Acorn House Victoria Road Acton London W.3. (c) Copyright 1970 by Speed and Sports Publications Ltd. All rights reserved. 4 contents page INTRODUCTION 7 chapter 1 OVERHAULING THE SIX CYLINDER ENGINE 11 chapter 2 IMPROVING THE LUBRICATION 21 chapter 3 BOTTOM END PREPARATION 25 chapter 4 MODIFYING THE EARLY 6 CYLINDER HEAD 33 chapter 5 BIGGER VALVES FOR EARLY HEADS 47 chapter 6 MODIFYING THE LATER 2000 AND 2500 cc HEADS 53 chapter 7 MODIFYING THE TR4 HEAD 63 chapter 8 THE ULTIMATE HEAD 69 chapter 9 PORT MATCHING AND DOWELLING 75 chapter 10 SPRINGS ROCKERS PUSHRODS AND TAPPETS 77 chapter 11 ENGINE INTERCHANGEABILITY 81 chapter 12 STRENGTHENING THE BOTTOM END FOR COMPETITION 85 chapter 13 LIGHTENING ENGINE COMPONENTS 89 chapter 14 HIGH PERFORMANCE CAMS 95 chapter 15 CARBURATION FUEL INJECTION AND MANIFOLDING 105 chapter 16 ASSESSING THE RESULTS 109 chapter 17 THE TRANSMISSIONS 111 chapter 18 SUSPENSIONS AND BRAKES 137 chapter 19 BODYWORK MODIFICATIONS 153 5 6 INTRODUCTION IT would appear that over the last be used, ones, that is, which vary con- decade, Triumph’s policy has been to siderably in size, weight and power introduce a car of a basically modern output, we must build the rolling chas- design-and, over a period, develop it sis to cater for the most powerful en- to suit various markets. This policy gine it is likely to have fitted. This has been adopted in preference to the means the car can be a little over- more normal method of introducing weight for the smaller engines, thus an entirely new car for a given mar- resulting in a more sluggish car than ket. is really desirable. Up to a point, this type of thinking For an example, to take the Her- must be commended. Since the ma- ald/Vitesse range of Triumph cars. jority of Triumphs are endowed with The early Herald with its 948 c.c. en- a respectable level of roadholding and gine and an all up weight of around braking power, the only items which 17 cwts. could hardly be considered become vastly changeable are the the spriteliest of machines, rather it power units and transmissions. Since should be considered to be the heavy- the non-sporting driver is unlikely to weight amongst 1 -litre vehicles. With complain if the car has a far higher the introduction of the 1200 the weight level of roadholding than he is ever to capacity situation improved but was likely to use, the manufacturers have, still not altogether remedied. When in effect, killed two birds with one the 1600 Vitesse came along things stone. The two birds in question are, took a turn for the better. Here we had of course, the sporting and the a car which was not unduly heavy for nonsporting type of driver. its 1 1/2litre power plant. Not only did There is inevitably a disadvantage the car have-a good weight to capac- when going about things in this man- ity ratio, but also an engine whose ner, and this can be easily summed output could be substantially raised up as a weight penalty. If we design a to produce a relatively quick machine. car in which a range of engines are to But for competition purposes the 1600 7 Vitesse still lacked the edge needed number of us who could entertain the to make it a successful race machine. feasability of such a project down to When the capacity of the Vitesse was a very small minority. Our best plan is increased to 2-litres and the G.T.6 to ignore such a scheme and stick was introduced, one would have ex- with the more conventional pushrod pected the competition scene to layout. If we really went to town with change substantially. It would not down draft heads, fuel injection, etc., have been unreasonable to suppose etc., we could achieve a possible 190- that these two cars would have domi- 195 b.h.p. from the engine, although, nated the competition in their respec- might I say, this figure has yet to be tive classes, but this has not been the realized. Straight away we find we are case. Half the reason for this could down on the power of the F.V.A. en- be that old ideas die hard. The thought gine by 25 - 30 b.h.p. To a certain of one of Triumph’s products sweep- extent this deficiency can be offset. ing the field and making hay with the By an intensive lightening programme rest of the competition may not yet involving the use of as many have caught on. The idea that it could fibreglass components as possible, be possible and that they should do the weight of a Vitesse can be re- so is not altogether unreasonable. duced to just under 15 cwt. so a little Let us look at the situation in an of the lost power is made up for by analytical fashion and compare, say, having slightly less weight. Even so, the 2-litre Vitesse with some of its our power to weight ratio is still down successful competition rivals pro- by 8-1/2%. There is a possibility that duced by other manufacturers. For we can offset some of the disadvan- our purposes a good comparison tages of this lower power/ weight ra- would be to see if we can achieve a tio in the suspension department. machine with a similar performance Unlike the F.V.A. Escort, the Vitesse to an F.V.A. engined 2-litre Escort. If has an independent rear suspension. this can be done, then without a This means we have less unsprung shadow of doubt we can say a Vitesse weight to contend with which theoreti- can be competitive. cally should result in better road hold- The F.V.A. Escort has a 2-litre en- ing. Against this must be added the gine producing a power output in the fact that the Vitesse is one of the few order of 220 b.h.p. The overall weight cars which still utilizes a chassis which ready to race is about 15% cwt. and in all probability is not as stiff as a unit suspension is independent at the front construction body. The result of this but not so at the rear. The rear end is that our carefully planned suspen- on these cars is served by an ex- sion geometry may not follow the ex- tremely well located live axle. How act motion it was intended to. In point- would our hypothetical race prepared ing this out I may be leading you to Vitesse compare with this ? First off, believe that even a fully developed we should find it very difficult to match suspension will be inadequate for our or even approach the power output purposes. This is not the case. The of the F.V.A. engine without resorting Triumph rear end will give better re- to very expensive twin overhead cam sults than a conventional solid axle heads. Tuning Std Triumphs over but its superior 1300c.c. This inevitably limits the 8 9 ity might not be quite as much as one ideas will be put forward which are would expect. although untried based on sound en- Having made our comparison, it gineering practice. can be seen that a really competitive These ideas will show a gain in Triumph is not by any stretch of the power but the amount gained can only imagination impossible. It may be a be estimated. It has also been recog- bold assumption, but I would predict nized that not everyone is bent on pro- that we are likely to see far more ac- ducing an all-out racer, so all mods tion in the next few years providing described will start from square one no great restraint is placed on the situ- and progress from there. For those ation. of you who are not fully acquainted In an effort to encourage Triumph with your car, it is a good idea to pur- owners or would-be Triumph owners chase a workshop manual for the rel- on to greater deeds in the field of com- evant machine. This book is not in- petitive motoring, this book has been tended in any way to replace an prepared. In the main it will give tried owner’s manual but to supplement it and proved methods of obtaining for the purposes of achieving a higher more performance. Here and there performance. 10 chapter I OVERHAULING THE SIX CYLINDER ENGINE SINCE the conditions of the bottom ment in their original position. Check end of an engine can have a major the cylinder bores for wear. The stan- influence on power output, we shall dard sizes of the bores are as follows: discuss, thoroughly and in detail, how 1600 to go about building up the bottom end STD 2,6276-2.6287 with a view to extracting the maximum 2000 horsepower for a given state of tune. 2.9405-2.9416 If the car you are working on is sec- 2500 ond-hand and has seen a normal 2.9405-2.9416 mileage, then it is more than likely In the standard bores the pistons below par. It is also noteworthy, since are graded in three different sizes and we are on the subject, that 99 out of the bore clearance on a new engine 100 new engines can benefit as far will be between 3.5 thou and 4.2 thou as power is concerned by a careful (0.00350.0042).

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