Gun-drilled AAH cams...
Try as I might this is the best pic I can come up
with of the gun drilled cam bores. This is a shot thru the front (see the
machined flat for diamond-shaped pulley washer).
Shop that was supposed to do this misunderstood and "low-balled" me
on the $150 price over the phone. However, in their defense when I got there
they admitted up front they misunderstood and would split the difference with
me. Still made em over $400 if I
let them do it. When they found out I had a lathe they told me how to
make an adapter that could be built for less than $100. They even ran me some
CAD plans of their adapter free of charge. They didn't tell me the drill bits
to do this would cost well over $400ea and that 2 should be used, ie" one for drilling a small "pilot" bore
and the next for drilling to finish size. Dont wanna break these drill bits!!
But I have a whole new appreciation and understand of why they would've had to
charge me so much. Takes an entire (LONG) day just to gun drill a pair of these
and another day to drill/tap the rear of the left cam for Heli-Coil
or threaded insert to re-install hall plate for CPS (cam position sensor) after
drilling it's threads out.
I'll get a weight-savings on this mod later in the week (still have to
disassemble the extra AHH heads to get the cams out) but I'm guessing I removed
1/2 lb per cam or more. Whatever a forged 12" x 9.5mm
iron rod weighs. But at least 1 pound for the pair.
And I know that some are thinking eminent failure/doom on the horizon for me
with this one. But I'm thinking it aint EVER gonna happen. I spent a lot of time researching and talking
with people on this topic. I've left far more wall thickness than they
recommended using both incrementally and percentage-wise numbers and my cams
are forgings while their's are mostly cast billets.
Next I'll send these out and have em re-heat treated
and surface hardened, further increasing their strength. I'll also be doing a
high tech surface friction treatment. I'm also going to see what kind of specs
I can pick up from a custom grind. I'll stick to grinding only and not go with
any metal-plasma build-up enhancement that would add lift. I'll see if I can
make em better, increase duration and by how much or
stronger performing for my specific state-of-build with my custom heads and
that pesky 6,300 redline. If I can improve the performance, pick up some
additional torque I will. If not I'll run em as-is
after heat treating, surface hardening and surface anti-wear coating.