Tony, (see message below)
The whole idea of fully vs. partial counterweighting only relates to
performance in terms of the potential for shaking, (non-balanced masses
being spun at high speed) and the vibration causing harm to bearings,
leading to short bearing life. The thing is, of all the people who have
done this, and those who have driven their cars, none have reported strange
quivering at particular rpm's, or "I drove for 6 months and my dentist said
my teeth were coming loose" sort of stories. So this could mean a few
things: (please, others correct me if I have missed something important)
1. bearings sufficiently over-designed that their life cycle not compromised
by rotating un-balanced mass H-20 vs. balanced U-20
2. engine mounts are gooey enough that vibes not transmitted (although
revving with hood open would have raised questions from those in the know),
so the vibes exist, but something else (like the timing chain) breaks first,
so the effected parts get changed before life cycle is reached
3. we vary the rev's so much in our driving (flashback to Palomar Mt. Road)
that the harmonic vibes never really get time to set up resonance, which is
(usually) far more destructive.
What the heck, everyone says it works fine and nobody mentions short life,
so while we all could talk about numerous things that could be, these ones
don't seem to happen. I would heed their 'complete system' installation, and
use the same oil pump vs. crank set-up that has worked previous. It may be
that the lower oil pressure forklift set-up goes with lower temp oils, while
higher temp car oils and higher revs may need the U-20 oil pump. That may be
a key to longevity. Okay so maybe "15,000 RPM" Victor Laury can test
endurance better than me, (110k miles on my Ford, still original front brake
pads) but there are lots of supporting H-20 installations, which is better
proof than the "worst case scenario" warning of impending doom.
(sorry Victor, I couldn't resist. Clandestine reference to mis-typed 5,000
rpm statement.)
Fergus O, 69 2000 (forget "I wanna be like Mike, I prefer "I wanna drive
like Victor")
_________________________
Date: Tue, 06 Mar 2001 15:45:19 -0000
From: "Tony Genovese" <chaztg@hotmail.com>
Subject: H 20 vs. U 20 bottom end
...... being that the U series crank is
fully counterweighted, whereas the H series crank is not?
Is this a noticeable performance defecit if one uses the H series crank in a
street motor?
Tony Genovese
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