I think small amounts of filing might have been performed on the pistons.
Except in rare instances the sum of variation in weight of a typical piston set will fall in the range of 1.5 gr. (a good set) 2.5 gr. (typical) 3+ gr. (not so happy, but not that unusual a set) and even if only needing the lesser sum of material removal for balancing, as it would present, with observation, as notable.
I don't see any markings on the pistons in relation to the connecting rods either (i.e., #1 piston to be used on #1 connecting rod). I don't remember all of the particulars, but I think I recall particular pistons being paired with particular rods.
In relation to the balancing effort, the reason for matching a particular rod with a particular piston would be because the small end of the rod in weight and the the piston weight are offsetting (i.e. the rod pin-end is light, so one matches it with a piston that is heavy, or vise-a-versa), this theoretically reducing the sum of correction required to bring this reciprocating sum of the overall "bob-weight" value into line. This is sometimes practiced as a compromise as if the componentry in hand doesn't lend itself (structurally) to the sum of correction required otherwise. Or unfortunately often, the operator is just trying to reduce the effort in correction required otherwise in the balancing process!
The part I'm a bit confused by is the rod bearings still being shrink wrapped in their original packaging, so I have no way of knowing if their weight was factored in?
So my question is, should I be concerned about the rotating assembly being balanced properly?
Most of the time, we know what a pair of rod bearings will weigh, so we don't bother to open up a new package. But to answer your question, leaving a pair of rod bearings out of the bobweight could cause some issues, that's 30-35g that's part of the equation on the rotating side.
As stated, most shops with any history generally already have the more common bearing weight applications recorded; but do note that the bearings increase in weight in instances were the crankshafts have been turned to an under-size (and the crankshaft throw got lighter!
), and if utilizing a "narrowed" or "chamfered" bearing, it gets lighter (but with the increased radii the crankshaft throw, it gets heavier!
); and then also one must realize that an FE crankshaft might be utilizing an FE bearing, or a BBC bearing, maybe Chrysler "Hemi" bearing, even SBC!
So all of this needs to be considered if the shop is falling back on that recorded information vs. just weighing the actually intended bearing, which really probably is the wiser practice when possible.
Oh, and just to aid in clarifying things: yes, 30-35gr. is a reasonable range for a single set of FE rod bearings to weigh, but remember that in the standard balancing practice here, there are two bearing sets attached to the singular throw that are included in the typical calculation of the "bob-Weight", so that's a sum of 60-70gr. in the total bob-weight value up for consideration!
And there is no "quicky-fix" here; you either accept that which you currently have, or choose to have the "revolving" and "reciprocating" assembly re-balanced (yeah I know, hopfully, properly!
)!
Scott.
