Saturday 2nd May 2020 – 6C Sprint

I wasn’t expecting to be able to post an update on the Alfa so soon, but the original creator of my little 6C Sprint, Philip Herrick, has very kindly provided me with some more information about how this bonkers little car came into existence, and also how he constructed it. You can read his ‘Engineering Principles’ below, and also see some photos of the car soon after it was completed and in much better condition than it is today. I haven’t edited the document he sent me, and I’m sure you can agree that it makes for interesting reading. 

When I saw pictures of the Alfa Romeo Sprint 6C I was inspired. I rapidly found that there was very little information available, only a few pictures of what seemed to be two cars built by Autodelta for Alfa Romeo. Only one car seemed to still exist in the Alfa Romeo Storica museum, which was closed. 

   There was one build project in Australia in addition to the Giacotolla cars, one project in Scandinavia and a further running (rally cross?) car in Israel(?). Another few pictures of a British built car with a Renault V6 were found after I finished building.

 To build a replica would be very expensive as a ZF trans axle would be needed. Therefore I decided to build “My version” of the 6C, not a replica.

In view of my circumstances, I opted to use as much Alfa Romeo designed and constructed components as possible.

 Thus the 164 sourced engine and gearbox were kept mounted on the 164 sub frame. This was mounted on the 164 inner wings as standard. This means the assembly can be dropped out as a complete unit, as per a 164, if needed.

 The 164 inner wings were welded into the Sprint rear body. The front of the inner wings is welded to the floor around the base of the “B” pillars. A large steel rectangular box section has been welded into the sill running to the base of the “A” pillar to distribute the torque engine force. The rest of the inner wing is welded to the middle of the “B” pillar, the edge to the window opening and the rear “C” pillar. Transversely the front of the inner wings has the original 164 cross member (reversed to give more cabin room and slightly narrowed to give the rear wheels a negative camber). The rear of the inner wings is also transversely linked using the Sprint rear seat floor/bulkhead panel (reversed and reinforced with extra steel tubing). Thus the inner wings are now supported front and rear, compared to the original 164, where they are only cantilevered out from the front bulkhead/”A” pillars.

  The 164 inner wings and sub frame also provide the mounting points and geometry for the 164 strut suspension. I did bring the top of the struts slightly further in to give a small amount of negative camber for the rear wheels. The redundant power steering rack was retained but given two locking bolts and stripped. Thus there is no steering or bump steer effect. 

  Access to the engine at the front and rear has been facilitated by having the sheet metal panels bolted in place. There is a useful sized boot and the engine ECU is mounted behind the NS rear wheel arch. Three engine relays are in front of the NS wheel arch.

  The front suspension and steering is standard Alfa Romeo Sprint, but the springs (front and rear) have been shortened to retain the ride height, as there is no front engine or gearbox and the body is much lighter than a 164. This obviously gives a stiffer ride but the car handles very well and was comfortable. The ride was compliant and gave very flat cornering with excellent “turn in”.

  The brakes are standard servo assisted system with Sprint discs at the front and standard 164 front discs at the rear. However, these use the standard 164 rear calipers (with a bespoke mounting plate) to reduce the braking force (Compared to its previous use as front brakes) and provide a handbrake mechanism. (This system easily passed the MoT requirements and proved very effective on the road).

  As all Sprints, that still exist, were built in the 1970/80’s and I knew that I would be altering the body, I did not want to/could not afford to cut up a good Sprint,  so I started with “A rusty Sprint for spares” from eBay. In the event, much of the rusty bits were removed but I did repair the bottom corners of the windscreen using modified Sud sections (Sprint sections not available). 

   The rear wings needed a lot of work to flare them over the wider rear wheels and wider track. I used MGB rear wing lower repair sections curved and welded all round to the flared and blended Sprint metal. It was difficult to get the two sides symmetrical, working in the confines of a narrow garage! Other bodywork repairs were done using metal welded in and body filler (7 areas  in the roof alone!).

  The front wings were replaced by fibre glass replicas – as I might have wanted to flare them for wider front wheels.

  The rear hatch had the glass removed and fabricated steel slats made for engine cooling. I did consider fibreglass slats, but thought the heat might cause distortion.

  The hand brake was from the 164 as was the gear lever. The mechanisms were created to suit the new locations.

  Electrics use the Sprint loom with the 164 engine loom. Instruments are standard Sprint 

(Note:- the Rev counter is for 4 cylinders…. so you are safe to use up to 9K indicated with the 6 cylinders….)   

  Cooling uses the standard 164 radiator with an electric fan. This, together with the “dragster fuel cell” petrol tank provides a bit more weight to the front of the car. The fuel cell is safer than a conventional petrol tank but is obviously in a slightly more vulnerable part of the car, but no more so than many rear mounted tanks.

 The cooling system did cause problems as the engine needed an additional expansion tank to eliminate air locks in the block due to the low transfer pipes to the front radiator. There were also leaks in the front expansion bottle and radiator core, which were only apparent when pressurised….A new radiator and expansion tank were bought and fitted.

I also considered whether a roll cage was needed but decided that as the car was only to be used on the road and not raced or rallied, the standard bodyshell would be suitable. Also the two Alfa prototypes had no roll cages.

 In conclusion I did build my version of the Sprint 6C. It used a more standard bodyshell and had a more easily installed engine and gearbox. It used far more standard Alfa Romeo parts in its construction. It had more space inside and a useful boot. 

 I enjoyed the challenge of creating my version and using it on the road. I am also pleased that it still exists and will have some more care and attention.’

Some of the detail included in the document above will surely prove to be very helpful when it comes to the time when we’re preparing to strip the car down and restore it, and I’m sure I’ll find a few small ways to leave my own mark on it. I’m very curious to see what the car weighs,  both before and after we restore it. I’d also love to see the weight distribution,  but also how much power the car is putting out with that sonorous Alfa V6, and whether we can improve on that a little. I think even simply removing that very heavy steel tailgate could do wonders for the car, and hopefully we’ll be able to create an aesthetic that is closer to the original, though that might mean a trip to the Alfa museum in Italy.

In the next section you can see some images of the car when it was originally purchased, including all the rust, and then when it was under construction and some more detail on how it was completed. There are also images from when the car had been completed and was being used. You’re also able to see a couple of images of the car that inspired this project, which looks quite special to my eye.

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