Summary of what we know up to now about the Giulia Sprint GTAm prototype
Here is a summary of what we know up to now.
Please bare with me, first of all I am stating the facts that we have verified with the sources mentioned. Double checking is mentioned if necessary.
Verified facts about the car:
A Giulia Sprint GT (105.02) with chassisnumber AR 603142 from 1964 carries an Alfa Romeo engine with a “hanging oilfilter”, a 16 valve head with a waterpassage on the exhaust side, single plug ingnition, a Lucas sliding throttle fuel injection with a metal plenum. The bodyshell is a “widebody” version with roll cage without a slittone rear suspension. The car has the single brake booster (for a car with standing pedals). The lettering on the boodlid says 1.5 16V.
The chassis number AR 603142 was manufactured on the 27th April 1964 and was sold on the 30th April 1964 in Milan, Italy. The body colour of this Giulia Sprint GT was Alfa red and it had a blue interior.
I translated the RIAR (Registro Italiano Alfa Romeo) document from 1987 with internet so that we all can read it. The text says:
"With reference to your question, we are pleased to inform you that the Technical RIAR Board has reviewed the documentation sent to us and gave permission(?) for the approval of this/your? car.
Therefore, we send the nameplate marked no 258; approval for the engine only.
We remind you that the cost of any such plate is 50,000 (lire?). Please kindly sent the money by check or money order.
With the most cordial greetings,"
This car was offered at auction on the 18th of January 2014 by Coys with an estimate of 110K – 130K Euro’s. The car was sold for 87K Euro’s.
The book "Alleggerita" (1st edition from 1994) mentions a number of developments of which one was:
1500 Marino 91” – 16 valve
Designed and constructed by Autodelta in 1970
Displacement is 1496,8 cc bore x stroke 83,4 x 68,5 compression ratio not mentioned
Monosleeve, small cilinderhead, 16 valve, ?? injection, slide throttle, single plug ignition
Approx 180 bhp at 8000 rpm bench tested ??
Probably only three engines made
Pictures from Francesco Tavoletti show this engine
If the engine in the car is indeed a 1500cc Marino 91" (that has to be double checked) and if indeed Autodelta designed and developed this 1500cc Marino 91" engine in 1970 (it would be good to verify this through a second source) it is unlikely that AR 603142 Quote "was used as a development car for a very special engine, basically the forthcoming GTAm but with 16 valves and a Lucas injection system" Unquote as Coys states in the text (see below). That is because the GTAm car and engine were developed before 1970.
And because of the sequence in time (1500cc Marino 91" designed and developed in 1970) it is unlikely that Quote "A lot of the things tried by Autodelta on this car were put into the GTA" Unquote because the GTA was first shown at the RAI autoshow in February of 1965 and thus designed and developed before that date.
Here is the complete text Coys used for this car
Quote ”Estimate: €110,000 - €130,000
In 1962, the successor for the very popular Giulietta series was introduced. This car was the Alfa Romeo Giulia, internally called the “Series 105”. The coupé of the 105 series, used the shortened floor pan from the Giulia Berlina and was designed by Bertone.
At the time, Alfa was very active in Motor sport. Autodelta , the racing division of Alfa, developed a car for competition that closely resembled to the road going model. These cars were named GTA instead of GT, the 'A' standing for “Alleggerita”, Italian for lightweight. The GTA was produced first in 1965 as a 1600 (1570 cc) and later as a 1300 Junior version. The GTA auto mobiles were also manufactured in either street (Stradale) or pure race (Corsa) trim.
The GTA had aluminium outer body panels instead of steel, (the inner steel panels were also of thinner gauge, the inner and outer panels were bonded and pop-riveted together), magnesium alloy wheels, clear plastic side windows, an aluminium rear upper control arm, different door handles and quarter window mechanisms, and lightweight interior trim. The engine had a new double ignition cylinder head (called twin plug, later in the eighties the system was called twin spark) cylinder head with a Marelli distributor from a Ferrari Dino, 45mm carburettors instead of 40mm and magnesium camshaft cover, sump, timing cover and bell housing. The transmission gear ratios were closer than standard and the gears were machined for lightness and quicker shifting. In full race form this engine could produce up to 170 hp. The 1600 GTA did not have a brake booster and had a thicker radiator than the standard vehicle. For homologation 500 cars were made for racing and road use.
The car in our auction is a rather special one, it is basically a Giulia Sprint GT but it was heavily modified in period to race specification just as the the forthcoming GTA´s was. It was used as a development car for a very special engine, basically the forthcoming GTAm but with 16 valves and a Lucas injection system.
This engine was very powerful, producing 208 bhp as opposed to the later GTAm´engines that produced 150- 160 bhp. It proved too expensive for Autodelta who did all the development work and who opted for the GTAm s twin spark design instead. This prototype engine was, according to the vendor, later used in a World endurance speed boat record attempts by boat maker Molinari.
A lot of the things tried by Autodelta on this car were put into the GTA and this prototype´s mechanical specifications are similar to that of the quickest race prepared GTA´s, it also has a shorter ratio gearbox. This car is an important part of post-war Alfa Romeo history and is also certified by Registro Alfa Romeo.” Unquote.
Last edited by Zagato_Olaf; 01-26-2014 at 03:42 PM.