Hi Norm, what a treat, another hybrid engine question! I'm assuming your boys are using a metric crankshaft and crankcases to suit, and that their racing regs allow later bits to be fitted in their class...
If I may refer back to my recent (and rather drawn out) explanation of my classic/AVL bitsa, probably the easiest way forward for this is to use a late set of classic Bullet crankcases, as the timing side casting has the alloy "blobs" in place to match the scavenge oilways on both classic and AVL timing covers, which ones got drilled depended on whether the engine was to be an AVL or Classic.
From the picture there are two oilways involved, the lower oilway for the scavenge side is already in the right place for either timing cover, it is 1 and 2 in the picture we need to concern ourselves with. 1 is the original oilway for the classic cover, this is drilled and tapped for 6mm and a home-made(!) slotted grub screw is Loctited into place, the top flush with the joint face, and not too long in order not to block off the vertical oilway underneath. At 2, you simply drill through to reach the vertical oilway which leads to the rocker feed, using an AVL timing cover gasket as a guide. The crankcase in the picture was an older one with an extra blob of alloy weld added in the correct position.
There is a bit of a trap for the unwary here, owing to the increased volume of the AVL gear pumps compared to the earlier plunger versions, and attendant wet-sumping issues. Namely if the scavenge oilways are at all restricted the wet-sumping will become an issue, whereas on an Electra-X, if everything is hunky-dory (yes, I know...) any wet sumping is usually cleared immediately the engine starts. Paul was aware of this when fettling my ASBO 12 engine and drilled out all the crankcase oilways to 5mm improve the flow.
This leaves the classic timing side crankshaft needing an oil feed. Perhaps you could braze a steel tube into the crankshaft end and grind it to the correct size for the oil seal in the AVL timing cover or get a custom timing side shaft made if the classic and AVL timing side shafts are not interchangeable.
The timing cover may need further work depending on the type of ignition and cam spindles used. If it's a crank-mounted CDI racing system you can just remove the idler pinion spindles fron the crankcase,and if the contact breaker/magneto hole is already blocked off, fine. If there is a magneto or contact breaker drive in use, both the alloy bosses in the timing cover will need finishing to fit over the idler pinion spindles and the pinons themselves. If the engine has adjustable cam spindles that's proably it, ther timing cover can now be properly fitted. If the engine is using fixed cam spindles, these are 5/8" O/D at the timing cover end insted of the adjustables' 15mm, so you will have to drill/ream out the timing cover to accommodate these.
All that then remains is to make sure the oil is flowing through the rockers freely. The downside with the late cases is the lack of pressure relief valve which the old ones had next to the 1/8" BSP union for the rocker feed. With the extra volume of oil from the AVL gear pumps it might be worth reinstating that or fitting our hosts' rocker feed PRV.
I think that's everything...
A.
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