In message <9311092023.AA08724@vinny.cecer.army.mil> Marcus Tooze writes:
>
> A couple of people have mentioned that I shpould get my engine balanced
> since I'm rebuilding it. What does this involve? What parts do the machine
> shop require? Should I assemble some of the bits, or do they 'balance'
> each part individually? How much is a 'basic-balance-job'?
>
> cheers
> Marcus
Marcus,
In my area a machine shop balance costs about $100.
Before balancing, the crank should be magnafluxed, ground down if necessary, and
polished. The pistons should be fitted to the rods with new small end bushings
(reamed for proper clearence.
What they do (asumming they have dynamic balance equipment):
They weigh the rod piston assemblies and take metal off three untill all four
weigh exactly the same.
They put the crank onto a dynamic balancer and spin it then drill out metal from
the heavy side (like getting tyres spin balanced, but they take off weight
instead of adding lead fishing weights). Once the crank is done, they bolt the
flywheel on to the crank & do it again, taking metal off the flywheel. The next
do this with the clutch diaphram in place. Finally they add the crank timing
gear, pully and fan and do it one last time.
Everything attached to the crank except the clutch disk and rods with pistons
are dynamically balanced (fan, shaft, pully, timing chain gear, crank, flywheel,
and clutch diaphram). The rods with fitted pistons are statically balanced.
Think of the bumpyness of driving on the freeway with unbalanced tyres. Now
think about the same kind of thing happening in your engine with an unbalanced
engine. Its the same forces at work. A balanced engine is a happier engine
that given the same care & treatment will outlive an unbalanced engine.
Take care,
TeriAnn
TeriAnn Wakeman One of these days, I'll be old enough that
twakeman@apple.com people will stop calling me crazy and start
LINK: TWAKEMAN calling me eccentric.
408-974-2344 TR3A - TS75519L, MGBGT - GHD4U149572G, 109 - 164000561
|