I've just gone through the process of balancing and blue printing the
engine in my Fiat Cabriolet as part of it's build up for vintage racing.
What you have described is balancing the motor it involves step 1&2 as
described. Step 3 is done on a dynamic balancer the process is fairly
complex they install what they call bobweights to each of the rod
journals that simulate the weight of the pistons and rods. The
bobweights are filled with lead shot based on the weight of the
piston/rod and some additional math. The crank, flywheel, clutch, front
pulley, and bobweights are put on the dynamic balancer they spin it up
and and the computer tells them where to ad or remove weight. If a shop
only does a static balance their not really doing a true balance job.
As far as blueprinting goes I would suggest you pickup one of the many
books on the subject the one I have is :
The Step-by Step Guide To:
Engine Blueprinting
by Rick Voegelin
Published by SA Design
ISBN 0-931472-21-0
Blueprinting is one of those topics that is always a debate, each engine
builder will have a different definition in terms of exactly how far
they go when blueprinting an engine. If you have all the components in
your engine remachined within factory specs is it blue printed some will
say yes others will say no, does an engine have to be balanced to be
called blueprinted again it's a matter of who you talk to. Some will
even go as far as matching the flow of the ports on your head before
calling your engine blueprinted. Your best bet is to get some books on
the subject and decide for your self what you require for your
application. once you have educated your self you may find you can do
allot of the blueprinting process yourself. You will find that most
books on engine blueprinting use a small block Chevy for examples but
most of what they show applies to any engine. Most speed shops have a
book section and carry books on engine blue printing go spend $10-20 on
some knowledge before spending $1-3k at a machine shop.
One thing I found while blueprinting my engine was that I had a
variation of rocker arm ratios with the factory rockers they ranged from
1.41:1 to 1.45:1 ( they should all be 1.44:1) so I've got another set of
rockers and will have to sort through them to create a matched set
hopefully all around the 1.45:1 ratio. When I found this out I asked a
few engine builders I know about this and was told even after market
roller rockers will have some variation in ratio and that they arrange
them to have the highest ratio on the end exhaust valves and the lowest
on the center intake valves this has to do with which cylinders tend to
run richer or leaner.
One last note very few machine shops are setup to do true engine
balancing most send the parts out unless they do a lot of racing or high
performance engine work. Don't waste your money on a shop that doesn't
do a dynamic balance of your engine a static balance is like having your
tires static balanced and most of us have experienced how well that works.
Doug Hamilton
1960 Triumph TR3A
1963 Fiat Cabriolet
>Hey everyone,
>>
>> I'm looking for a definition of 'blueprinting' an engine. In my
>> understanding, it involves several things:
>> 1) Ensure all pistons are the same weight
>> 2) Ensure all rods are the same weights at both big and little ends
>> 3) Spin the crank/flywheel/pulley and remove material until all
>> vibrations are removed up to say 6k rpm
>>
>> Is this an accurate description? If I went to a machine shop and just
>> asked to have the engine 'balanced' what would I get, just #3 above?
/// triumphs@autox.team.net mailing list
/// To unsubscribe send a plain text message to majordomo@autox.team.net
/// with nothing in it but
///
/// unsubscribe triumphs
///
/// or try http://www.team.net/cgi-bin/majorcool
|