I feel far more confident to do internal case mods and material clearancing by hand these days and I intend to do several to the AS41 case.
Planned Case Modifications
Case – Interior
The interior of the 1/2 side of the case receives the most modifications and will include:
- Enlarging the main seal return oil passage by .5mm or so,
- Enlarge the oil return passage between main bearing #1 saddle and just above cam bearing #1 saddle,
- Enlarge the cam bearing #2 and #3 oil grooves (duplicate this on 3/4 side),
- Enlarge the cam bear/sump return oil passage (duplicate this on 3/4 side),
- Clearance material between main bearing saddle #2 and cam bearing saddle #2,
- Perform the HVX mod for the lifter bores oil passage and create the oil gallery in the cam bearing saddle #2 (if and only if there appears to be enough material to work with there
The various air passages behind the main bearing saddles will be opened and polished.
Case – Exterior
The external case mods are all pretty simple:
- Drill and tap the various oil galleries with the possible exception of the small one on the front that connects to the oil pump return passage (I am not seeing the necessity for this on a new 0 mile case right now) then plug them once case if fully cleaned,
- Drill and tap the oil passage for the exterior oil filter return line,
- Drill and tap the Type 3 sump hole cover to accept a VFD oil temperature sensor