Ford's 1964 Indianapolis engine
In 1963 a Ford-powered Lotus 29 driven by Jim Clark came tantalisingly close to winning the Indianapolis 500, and was prevented from doing so only by the leading roadster of Parnelli Jones dropping oil on the track. The Lotus was running a development of Ford's Fairlane pushrod V8; drawing pump fuel through carburettors it produced far less power than the competition's highly tuned Offys running on the more usual Indy brew of methanol. Ford, however, was keen to emphasise the racing pedigree of its road products and wanted to maintain a stock car image for its motorsport efforts.
It was clear that the 375 hp produced by the 255 cu in V8 was not going to be competitive in 1964, regardless of the quality of chassis, so work began to create a new, twin cam unit based on the Fairlane block. The overall development of this engine is interesting in itself, but of greater interest are the problems and subsequent solutions the Ford engineers found regarding the lubrication system. Although the engine in question was developed over 40 years ago, the lessons learnt are still applicable today.
Initially, the design team carried over the existing dry sump system from the pushrod engine, consisting of single scavenge and pressure stage pumps, with the oil stored in a tank towards the front of the car. The first problem the designers ran into was providing sufficient oil to the cam lobes, which necessitated an increase in size for the pressure side of the pump. This in turn placed a greater demand on the scavenge stage, not only in terms of the volume of oil needed, but also as a consequence of the increased tendency for the oil to foam as it drained back from the camshafts.
To counter this, the scavenge stage was doubled in size while the pick-up pipe diameter was increased by 50%. The result was a sufficient supply of oil to the bearings, in addition to adequate scavenging of the crank case.
Another problem the engine suffered from was excess oil being ejected from the breather system. The cause was identified as a combination of two issues: windage from the action of the crankshaft, combined with the large amount of throw-off from the reciprocating components caused by the large bearing clearances. It must be remembered that bearing and machining technology was not as advanced as it is today, and to ensure sufficient cooling and lubrication, race engines tended to run very generous clearances. The breather also needed to cope with the volume of air and gasses being drawn from the sump by the scavenge pump. The problem of breathing was solved by simply increasing the diameter of the tank breather system to reduce the internal tank pressure.
To increase the effectiveness of the system further, a second scavenge pump was subsequently added to the system, which also insured against failure of either pump. Overall, the changes made to the system sound very familiar to those one would undertake today in converting a road engine for race use. In summary they were:
- Redesigned oil pan baffles to control case windage
- Installation of baffles to prevent excess oil build-up near the timing gears
- Better control of oiling to the cams, and redirecting the sump return to prevent oil draining over rotating parts
- Increasing the scavenge pump capacity, with the addition of extra stages to improve effectiveness
- Venting of the oil tank to reduce blow-by
It is encouraging to note that even the mighty Ford had to deal with many of the problems that still beset competitors working on road engine development today - although most clubmen have to go without the benefits of a motor corporation's r&d resources!
Fig. 1 - This is the final iteration of the 1964 oil system; note the twin oil scavenge pumps with independent pick-ups (Courtesy of Ford)
Written by Lawrence Butcher