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ENGINE:
The 90° alloy V8 block uses dry sleeve bore sizes from 4 ¼" (107.95mm) to 4 1⁄2" (114.3mm) and will accept a standard Chev crankshaft but can also use a stroked crank to 4.5" or with extra machining to 4.750". This block is also available in the standard tall block configuration (.400") extra on deck surface which will allow for better connecting rod angle. The oil ways consist of a 9/16" (14.3mm) main gallery passing directly through the centre of the block. This eliminates a lot of sharp corners as in regular blocks. This system gives an almost direct line to main and big end bearings. The main bearings have steel 4 bolt caps with the rear main consisting of a steel 4340 cap also with 4 bolts (studs.)
The basic block is also available in magnesium, which gives about a 30% weight saving over aluminium. The final weight of the bare block is Aluminium - 52kg, Magnesium - 37 kg.
Dry sleeves are machined 0.5mm below the 4 1⁄4" bore dia. with the main bearings having approximately .25mm left in for line boring and honing to final size. The block has a number of ribs in various places across the valley and in the back which gives the block a great deal of torsional rigidity.
HEADS:
These heads have been the subject of a lot of design both on the flow bench and in operation. The top of the head has been raised by ¼" to allow for longer exhaust ports which are of the "D" shape. The inlet ports have been altered internally to give a flow ratio to within less than 1% of each other. Longer valves have to be used to accommodate this extra height. The valve seats can be large enough to accept a 2.300" (58.42mm) inlet valve with the exhaust able to accept a 1.900" (48.26mm) valve. A standard valve spring seat and retainer is used.
The combustion chamber is ll9c.c. in capacity with the ability to accept a second spark plug in each cylinder. However if a second plug is used then a fabricated exhaust manifold must be used, not a standard cast item. The head is available in both large and small port intakes, taking the standard manifolds available for any combination of carburetors, fuel injection or forced induction.
An extra bolt in the form of an ‘unbrako’ cap head is used in the floor of two intake ports to create a full circle of 6 bolts around each cylinder. This bolt is capped by a ½" NPT ‘0’ ring hydraulic plug in the roof of the inlet port, which in turn is locked into place by the push rod guide plate. The rocker stud bosses are substantial size with a full 25mm of thread for the longest rocker studs. Valve, rocker and push rod geometry is maintained by the head being totally machined in a jig and is not removed until finished.
AERO GEARBOX:
This gearbox is of a design that enables a number of features to be utilised. It is a balanced idler system from which drives are used on both idler shafts, one for the oil pump the other for the C.S.U (propeller governor.) The gears have a 12º helix that not only gives rise to quiet running, but also increases in strength. It is designed to run at a 700 H.P. continuous input, with a ratio of 1.45:1. This ratio will deliver an output speed of 2550 R.P.M. with an input of 3700 R.P.M. At the higher power levels an oil cooler will have to be used, which can be plumbed into the existing oil system.
The lubrication system delivers oil to all bearings as well as the pressure faces of the gears, each outlet is orificed to provide the correct flow to each position. The rear cover of the gearbox has a recess machined in it along with a circle of bolts, this allows the fitting of any bellhousing/adapter to be fitted to the gearbox.
The flywheel drive mechanism is of the damped variety to provide sufficient drive but eliminates as much of the harmonics of the propeller and gearbox passing to the engine as possible. The propeller mounting flange is a standard SAE No. 2 with the main shaft being hollow to allow for the passage of oil for altering the propeller pitch. All bearings are standard sizes but carry compliance from the manufacturers for aircraft use. In this form however they do have a very definite shelf life, at this stage 23 months, so it is important to use them A.S.A.P. The seals are also standard sizes but these carry no use by conditions.
The lubricating oil is a Castrol automatic transmission Dexron 3 which is available world wide.
The main case carries two side mounting flanges drilled and tapped to suit various applications. The idler shafts are also tapped and doweled to accommodate any oil pump of C.S.U. drive that needs to be utilized.
Overall the gearbox is of a robust design that has a calculated life in excess of 26,000 hours of operation. This however is as yet to be determined in practical operation.
All gears are case hardened and ground form and are checked for correctness by a comparator. After assembly the wear pattern and backlash are also checked to make certain there are no high spots or out of square teeth. A very rigid check of all the information is carried out and recorded for that particular gearbox. It also carries an identification plate with build number, date etc.
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