By Tony Roberts
When Fox Roberts Racing imported the M16 from San Diego in 1997 it had a ‘cooking’ cast iron five litre Chev V8 installed of about 400bhp. We presumed that the Americans had installed this engine so that the car could run as a Formula 5000 on the local scene. The suspension set-up and corner weighting was way out and the fuel cell was perished. After the first demo run at Whenuapai, we installed a new cell and sorted out the suspension, although the rear still had some basic problems and we then ran the car at the 1998 Formula Libre Grand Prix. At this point the car had the 10½ in clutch and a pull activated slave cylinder which made gear changing rather slow. The car’s weight without the driver was 1760lbs (800kg) and this meant that it was giving away over 300lbs to the F5000s. Driving the car in this condition was relatively easy because the weight of the car coupled with the large wings and lower power than the car was built for, made the car very stable. With the big wing on the back the car stayed ‘glued’ to the track and was predictable with very little wheelspin, even out of the hairpin. The amount of drag that the car generated, even with the wings almost flat, meant that it would only do 155mph down the back straight (15 mph slower than our big block Corvette!) Anyway, we really enjoyed this first race and with the attrition from accidents and breakdowns we managed to finish 4th at the end of 35 laps, with a best lap time of 1.01.2. The rear anti sway bar mount had come adrift, but otherwise we could have done another 35 laps. One thing that we have found though is that people in New Zealand expect a McLaren of any vintage to be competitive!
When the car first ran at Indianapolis in Peter Revson’s hands in 1973, it was powered by a 2.6 litre turbocharged Offenhauser engine making about 700bhp. The car was then raced by Salt Walther and others through the ‘70s at Indy and in 1979 was repowered with an aluminium 6.0 litre Chevrolet engine. The M16 then ran at Indy in 1980 and 1981 before being retired. The options we had were to either seek out an Offenhauser or go the stock block option. The aluminium 355 cu in stock block option was available from 1972 and would therefore be period correct as an option for the car. The availability of the Chev engines and the fact that the turbo lag on the Offenhauser would make the car difficult to drive on a non oval circuit swayed us towards the Chevrolet option. As luck would have it, an aluminium 355 cu in V8 was for sale shortly after we had run the car at Manfeild and we decided to purchase it. At the same time as installing the engine it was appropriate to also tidy up the clutch, rear sway bar mount, engine mounting brackets, dry sump tank leak, rear wing mount and general plumbing problems that the car had. The installation and general sorting out took longer than anticipated and we had the M16 only just completed before the Formula Libre GP of 1999. On the Thursday before the race I drove the car around for 20 laps at 4,000 revs to run in the new crown wheel and pinion and bed the brake pads. All the temperatures were good and just as I went out again to try the car for speed, the battery went flat!
Arrived at the track on Saturday, really looking forward to the drive, although a little apprehensive. The M16 had now shed 200lbs of excess cast iron (it now weighed 1540 lbs) and had just over 700bhp. I asked Duncan to set the car up with a fair amount of wing downforce as I was not sure how it would be to drive. Initially leaving the pits, the car felt much more lively, with an urgency it certainly had not had before!
Sweeping through Champion’s big curve and the esses the car felt great and much more balanced than with the previous heavy load in the back. Within a few laps we were well under the old lap times and once the tyres were hot and the car was straight, the acceleration was incredible, especially down the back straight where the M16 was now touching 185 mph. I only used 1st gear out of the hairpin once because the acceleration was so brutal I thought that the old car might break something. This is one thing you have to keep in mind when you are driving this car. It is over 25 years old, a genuine works car with a long history and probably worth more than me, so it’s not expendable and you have to drive within yourself. For the last practice on Sunday morning we eased the wings back for less downforce and I went out behind Graham Cameron. I guess Graham acted as a "hare" for me, as the first lap was in the 60s, then 59 seconds, 58 seconds, 57 seconds and then three laps in the 56s. Unfortunately engine problems plagued us in the race and forced our retirement after 10 laps. However, the team was well pleased with the cars improved performance as it now brings it to comparable performance with the top F5000s in New Zealand. The responsibilities we have to preserve this car and the other old McLaren cars were brought home to me in no uncertain terms by a few spins whilst trying to rapidly warm up the tyres at Manfeild last November. To this end, McLaren International kindly dispatched a set of old tyre warmers for use on the cars - with the warning - just don’t let the driver get too enthusiastic straight out of the pits! For next season starting at Manfeild in November, the engine will be rebuilt and slightly detuned to 650bhp. We hope to get in some practice track time to improve performance and we are intending to do the Ruapuna and Wigram meetings and possibly Teretonga in early 2000.
Today, the pair run Group 7 Sportscars Ltd, dedicated to building and supplying rebuilt and new parts for McLaren Cars.
Where is the car now? The car is currently owned by Harry Mathews in the USA but is up for sale (as at June 2007)
