65 Hipo Engine Balance

[mygt350]

When Ford balanced the 65 HiPo 289 rotating assembly, did they (Ford) include the flywheel and the thick balancer/hatchet, in the balance? I assume the balance excluded the balancer/hatchet and flywheel as those could be replaced during life of the engine without requiring a rebalance. 

Thanks in advance

[Bob Gaines]

When Ford balanced the 65 HiPo 289 rotating assembly, did they (Ford) include the flywheel and the thick balancer/hatchet, in the balance? I assume the balance excluded the balancer/hatchet and flywheel as those could be replaced during life of the engine without requiring a rebalance. 

Thanks in advance

Randy G is better at explaining this then I am but Ford did not balance the rotating assembly like your machine shop would. It was not as precise as that.  They engineered it so all of the components put together would have a acceptable balance variation range . They knew what the rods weight range ,pistons etc. etc. and it would balance within a certain range using components made to work together. Your machine shop for example can balance and compensate for eliminating the hatchet head counter weight with the precise equipment they use. Ford was mass producing the hipo engines and made it so the engines would all balance within a acceptable range with just bolting together the right components. Millions of other Ford engines were done the same way. It is not required for rebuilds but having your machine shop balance the rotating assembly helps your engine perform typically more smoothly then possibly the way it came from the factory.     

[gt350hr]

   Thanks Bob.
      Because the "assembly line engine" process was SO quick ( about an hour total) "precision balancing" was not a possibility. So "range" weights were used when the components like pistons , rods , cranks, fly wheels and balancers were produced. The entire assembly was built and then "final balance" was "adjusted" during the "run test" EVERY engine got before shipping to an assembly plant. This is called "mass balancing".  Your local machine shop CAN'T do this and has to resort to balancing the individual components.  Of the entire "rotating assembly" the "hatchet" is the one item with the least weight variation. Engine "balance" on a V8 is generally accepted as "50%".What that means is 50% of the reciprocating weight is bolted to the crankshaft throws and then the crank is spun ( similar to a tire) and then adjusted to be "in balance". Some engines are "internal" balance and others are "external meaning there is additional counterweight in the fly wheel and balancer to supplement the crank counterweights. An external balance engine must have the balancer and fly wheel/flex plate bolted on then balancing for obvious reasons. Mass balancing is JUST as good as component balancing , and balancing is very important in a performance engine.
     If you have more questions , just ask away.
    Randy

[mygt350]

Ideally, machine shop would gather all the rotating components and balance the complete rotating assembly. But, if needed to replace a balancer or a flywheel on an existing engine, could use a balancer or flywheel from another engine as long as the components were identical and were within the window of balance.

[mygt350]

Am curious how the "final balance" was "adjusted" during the "run test" which EVERY engine got before shipping to an assembly plant. Surely didn't alter crank or rods. So without pulling pan off completed engine, only thing to modify would be balance er or flywheel.
Since all HiPo 289 engines were not standard shift, how did they balance engine destines for automatic transmission?

[Bob Gaines]

Am curious how the "final balance" was "adjusted" during the "run test" which EVERY engine got before shipping to an assembly plant. Surely didn't alter crank or rods. So without pulling pan off completed engine, only thing to modify would be balance er or flywheel.
Since all HiPo 289 engines were not standard shift, how did they balance engine destines for automatic transmission?

What makes you think automatics are done any differently ? Of course automatics have a flex plate instead of a manual flywheel. The Hipo flex plates are weighted differently in the same way that manual flywheels are weighted differently compared to non Hipo engines.

[J_Speegle]

Am curious how the "final balance" was "adjusted" during the "run test" which EVERY engine got before shipping to an assembly plant. .............

There was no "final balance" done nor "adjustment". Either the engine passed or didn't. If a vibration out of the ordinary too place the engine was not shipped then likely scrapped or disassembled and evaluated by others if there were multiple examples suggesting a possible issue or problems with the parts used to assemble the same engines. Then it would be a specific shipment or supplier issue from there once determined

[mygt350]

Jeff

Was curious because Randy G make the comment "The entire assembly was built and then "final balance" was "adjusted" during the "run test" EVERY engine got before shipping to an assembly plant". That statement got my interest up.

So engine was started and if it was within some vibration specs, it was sent to installation. If it failed, it was send somewhere else...

[mygt350]

Bob

Am having difficulty understanding engine balance using flywheel and same engine using a flexplate. Understand each has weights, but they are many pounds different in weight. Just thought the rotating weight would be significantly different between the two.
That said, assume an engine originally shipped with a flywheel, could be used in a automatic application without adversely affecting balance??

[J_Speegle]

Jeff

Was curious because Randy G make the comment "The entire assembly was built and then "final balance" was "adjusted" during the "run test" EVERY engine got before shipping to an assembly plant". That statement got my interest up.

So engine was started and if it was within some vibration specs, it was sent to installation. If it failed, it was send somewhere else...

Since Randy made the statement I guess it would be best for him to answer what he meant by the statement.

For your other flywheel related question rotation total mass weight and balance are two different things if I understand correctly

[mygt350]

Since an engine may have a flywheel for a standard or a flexplate for a automatic, am really confused just how the flywheel/flexplate is used in the overall balance equation.

[gt350hr]

   When the engines were test run at the Cleveland assembly plant the balance was adjusted 'if " and as needed by drilling the flywheel or flexplate. On flexplates , you may also see small squares spot welded on to them. Service part will not have them. On the balancer you might see holes drilled into the end , or a small steel rod added to one round holes in the hub. Mass balancing is just as accurate but "could" change if any one of the components were exchanged.
   Component balancing is done around a "Bob weight" no pun intended. Bob weight is the sum of rotating and 1/2 of the weight of reciprocating weights. A special fixture is used on the rods to determine "big end" weight and small end weight. both of the big end weights are used but only one small end weight plus one piston , pin , and rings weight are used. This is often around 1200 grams or more. This weight is then added to the crank throws ( all four) with special clamp on weights. the crank is then loaded into the balance machine and the fly wheel / flex plate and balancer are added . The crank is then "spun" and any out of balance is corrected the same way as a mass balance by adding or subtracting weight from the balance or flywheel flex plate.
     Randy

[pbf777]

They engineered it so all of the components put together would have a acceptable balance variation range . They knew what the rods weight range ,pistons etc. etc. and it would balance within a certain range using components made to work together.

     This probably what one should concentrate on in understanding the balancing procedure utilized by Ford (and others) in this period.  In other words for example the O.E.M. would engineer, say for a connecting rod, establish what was required dimensionally for function, this would lead to the resultant mass and typical weights in manufacturing, and then with the variables exhibited in the manufacture of one component versus another it is necessary to balance or one might prefer the term to 'equal-weight' them in the appropriate fashion, this generally via the removal of the parent material through a grinding or milling operation in the deemed appropriate and provided for locations.  Then even though the weight differentials have been narrowed their still exists a resultant tolerance value remaining necessary for mass production efficiency so then units are often batched by simular observations to further reduce the differential; all of this in each step with "acceptable" tolerance specifications, with individual units often being tossed (or redirected from Production to Parts & Service  ) when failing to equal such along the way.  This process most represents the "reciprocating" (stuff that moves up & down  ) balancing effort of the connecting rods (big-ends & small-ends) pistons, gudgeon pin, and known sums for the rod bearings, piston ring set and piston pin retaining rings/locks if applicable.  This providing a "bob-weight" value, typically in the American V8 (but not so in other engine layouts  ) a sum of 50% of the reciprocating (rod small-ends, pins, locks, ring set, etc.) and 100% of the revolving (rod big-ends & bearings), in the balancing effort.

     The "revolving" (stuff that goes round & round  ,  crankshaft, damper, flywheel or flex-plate, etc.) balance process requires a 'spinning' operation with establishments of the effects of the reciprocating values in place and then corrections  to create the desired effect, this via removal of excess material provide for as before. Unlike the local machine shops where it is required to establish "bob-weight" fixtures to simulate the effects of the rods & pistons etc., here the O.E.'s for efficient manufacturing have tooling set-ups that create the imbalance effect and the revolving units (crankshaft or crankshaft dampers or flywheels and flex-plates) are balanced, or perhaps actually imbalanced to counter this establishment, or what we in the balancing business say: to "neutral" the assembly, and whether the net result on the component is neutral balanced or providing a counter-weighted imbalance value is dependent on the set-up. But again, this to a tolerance outlined by the O.E.; one which at the local machine shop is suppose to be bettering.

     And then yes, as stated above, all of the appropriate components are then assembled, having never seen one another previously, this unlike the procedure required for the local machine shop balancing effort, and it all 'should' fall within the manufacturers' acceptable tolerance; but it is the potential 'stacking' of tolerances exhibited in each individual component that really causes the problem, and here is where the factory wasn't able to compete, and even though the local balancing effort 'should' provide a narrower deviation in weights and balance, as we have all of a singular assembly in front of us and invest a greater time element. 

    "Balancing" is a rather complex subject, and there are differences of opinion on what a "balanced" unit might really be, so read up on it if interested, cause I type way-to-slow to be able to present all of the nuances here.

     Scott.

[gt350hr]

  For a slow typer you sure are flowery.

        45 years ago I was at Holman Moody in Charlotte. I watched a guy assemble a Boss 429 short block. He opened a brand new box of TRW pistons and put them on the rods and eventually into the block. I questioned him about not balancing or even checking the piston weight of the assembly. His response was "what goes up and down isn't as important as what goes 'round" . "If you want to make an engine shake , pull a plug wire" . "All them pistons still weigh the same!"  His name was Robert Yates (rip). I learned something that day. balancing to a "quarter of a gram" may be fine for a Swiss watch but an automotive engine doesn't care.
   Randy

[pbf777]

"what goes up and down isn't as important as what goes 'round" .

     I don't disagree, just that in order to 'balance' the stuff that goes round & round accurately, one needs to have reasonably accurate bob-weight values, and in the case of the American V8 with four crank trows it is generally practiced to have these bob-weight sums consistent, this if only for the self cancelling attributes of these items in motion making for simpler offsets somewhere else; though if one weighs each component and accounts for variances in the bob-weights then what the heck!  Though I would yield to the expediency factor, still I would consider it poor practice, as remember, nothing is perfectly "balanced", we are balancing these assemblies from only a singular perspective and allowing the remainder to be accepted or ignored, and reducing as many of the known variables aids in exposing the otherwise unknown.   

     As an example, I have been involved with the light aircraft racing guys (don't tell the FAA  ), these mostly being the 180° flat-six air-cooled units of Lycoming manufacture, and often one finds that although connecting rods attached to opposing cylinders and crank journals will prove relatively consistent in weights, the next opposed set many be significantly different, and so on!  Here we see the self cancelling of the opposed banks (remember 'flat' engine configuration  ) consideration, but not that they all need to be equal.  I have thought that the reason for this practice is as the mass of a thing changes so does the frequency of the point (R.P.M.) of 'critical' vibration, therefore if the components of the unit are of a different mass, then they won't pass thru this critical at the same R.P.M., and this reduces the cumulative effect on the hole.  But in these racers' it is practiced to match rods into sets of equal weights.

    Just food for thought, .......... or perhaps just fertilizer for the flowers!

     Scott.