> Drilling a hole at the bottom of the lifter would be similar to a large
> pit. Pits are said to cause a more rapid decline of the lobes.
> This might be the reason that this "extra" oiling has never been
> practiced.
>
> Dick
I disagree. As Darrell Ramsey pointed out, PRI offers the weep hole in
their TR6/GT6/Spit lifters. Crower also offers to drill weep holes in their
lifters as an option when you order. And I consider Crower's engine
products to be some of the finest in the aftermarket, although they really
do not do much British stuff.
A pit is a breakdown of the metal at the surface of the lifter, where it was
inevitably softened over time. Whereas a purpose drilled oiling hole would
be chamfered and micropolished so as to have no negative effect on the cam
lobe it rides on. Additionally, the material surrounding the oil hole
should be of the same hardness, especially if it was re-hardened after the
drilling process... which it should be, as you will be piercing the hardened
surface to make the penetration.
These lifter oil holes are REAL small. Crower's hole is .024" in
diameter... and looks more like it was created by a precision needle than a
drill bit.
The oil holes are just not common place in the British realm of engine
building.
Kai
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Kai M. Radicke
Wishbone Classics
www.wbclassics.com
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