Moving on to the new tappet/bore oiling system.
Although these lifters are super quality it's Achilles heel is the oil groove width.
At 4.8mm it's less than half the size of a stock hydro unit so it's critical how it aligns to the oil gallery hole throughout it's travel.
Ideal world is 100% unrestricted oil flow regardless of tappet position but that won't be possible.
I have no idea if the case oil gallery is the same position as on a T1 engine so I need to check anyway.
First popped in the cam to get some max/min lift positions in relation to the lifter bore deck height.
Next bad news coming.
FFS, i can barely squeeze a 0.7mm gauge in there, in fact it's 0.5mm.
This is half the clearance I need so the bore depths are all wrong and need re-cutting.
Ok, moving on, placed a drill bit in the bore and checked the bore depth from the top.
Now the depth of the lifter to the oil groove.
This was actually 22.7mm rounded up upon rechecking.
Put my hot ms paint skills to some good use and we have....
Did some quick maths...
13.5 - 18.3mm oil groove range at minimum lift
22.2 - 27.0mm oil groove range at maximum lift
22.9 - 29.9mm active oil feed range
9.0mm total lifter range
4.1mm total active oil feed range
Oil feed range 45% of lifter range.
So, you read this far then?
Here's the kicker.
I never actually saw these bush inserts, only the T1 style ones.
I've just noticed a recess behind one of the oil feed holes and it's just dawned on me.
There's an oil groove around the outside of the bronze bush that allows oil to pass from lifter to lifter with only one feed hole necessary, in fact it can be positioned anywhere around the bore.
All the ones I have seen have the oil groove cut inside the bore so I did not even consider this!
Ok, good news.
I have a 100% active oil feed to all the lifter bores plus an extra hole to improve oil feed to the drive train.
I have just ordered a bush bore tool from Gene Berg direct and will sort the bore deck heights.
Who say's building engines isn't fun?