Randall, List,
sorry, I didn't mean to become 'unbalanced' and rant about the flywheel.
Randall, if switching to the aluminum flywheel made the engine smoother, I
would venture that your old flywheel & pressure plate assembly were
probably out of balance. Most likely, the pressure plate...but who knows.
I would THINK that maybe a more heavy flywheel would dampen
vibrations, but that's pure speculation.
When I had an original style 3-finger pressure plate balanced with the
original flywheel, the machinist had to weld a little 1" piece of 3/8" rod
on one side of the pressure plate just to get the thing in the ball park.
This was a rebuilt Borg & Beck unit.
Jim mentioned rod balacing 'end for end' rather than just weight matching.
If you consider that the big end of the rod is traveling in an elipse WITH
the crank as it rotates, you WOULD want the big ends of each rod to be the
same weight ideally. If the big end of one rod was heavier than another,
this would amount to the crank itself having one of its journals heavier
than another.
So, in other words, go ahead and have the rods balanced end for end. That
was the least expensive of the balancing costs.
In all, I think the balancing cost between $200-$300 here in Santa
Barbara, California. Most services (and everything else) here tend to be
pricy, so YMMV. (And by the way, gas just hit $2 here)
But Jim also mentioned one OTHER often debated points of TR2-4
motors.....to install a harmonic balancing crank pully or not.
I've yet to pop for the harmonic pully. I polled a few racers and found
the following scenarios in race cars that are being revved high:
1. Harmonic Balancing crank pully installed. I think you can get them from
BFE. Seems like I heard once that they were a V8 pulley machined to fit
Triumphs.
2. Original fan extension installed, but no fan on it.
3. Just the original crank pully sans fan extension.
TeriAnn Wakeman has a harmonic pully on her car and she spanks it pretty
hard (5700 rpm shift point I hear) and she swears by it based on research
from the FOT list. There is reportedly a harmonic around 5500 with the 4
cylinder TR motors that likes to fracture cranks and\or cause the center
bearing to take a beating due to the crank 'whipping'. But again, there
are racers out there who are revving past 6 grand without it.
I'm still shifting below those nether regions at 5000-5200. It might take
a more radical cam (or perhaps just more nerve) than mine to get up
there. I have a Isky grind with a 268 degree duration. I think that puts
it in the 'warm' cam category.
If anyone else on the list has a harmonic pully, would you care to share
your experience?
-jeffrey
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