There have been some posting on balancing pistons, rods, flywheels. I can see this for those who want to gain performance from the side-valve engine. My question is did the factory engine builders (from 1907-1927) spend time in building engines that were balanced and vibration free? What was considered a suitable factory engine for public sale?
Are there any indications on engine parts that they were factory balanced? Don't recall it being mentioned before + usually, if checked say on a modern re-build, most stuff needs balancing.
"...building engines that were balanced" YES
"...and vibration free" NO
You can find factory balancing holes in flywheels and see where stock has been ground of off crankshafts. I don't believe I've ever seen any balancing techniques done to connecting rods that appeared to be "factory". I think that what was good enough to run well at 30 mph or so was most likely their goal.
Most things need balancing today because; 1. We drive faster 2. Parts have been mixed up from multiple engines & transmissions. I'm sure that con rods made from the same lot probably had roughly the same weight. They may have even been sorted by weight, if not actually balanced. But, that's all out the window after 100 years of parts swapping.
Yes, flywheels have balancing holes drilled in them. But in taking apart transmissions looking for usable drums, I've never seen any evidence of balancing there.
I seem to recall that the rods and pistons were a "matched set" individually. They were weighed and grouped by weight. On an engine assembly, all rods and pistons from the same group were used. No effort was put into making them exact by grinding, etc. They were just in the same weight range. Such as Group A, B, C, D and one group may have had a weight difference of one ounce from the next group. (Or whatever the spread was. I don't recall.)
I just said "one ounce" but I think it was less than that. Perhaps 1/4 ounce. That's about 7 grams. It's in the Ford Methods book if someone wants to find it. There's no documentation about the later years but the procedure was probably the same.
I remember reading, some decades ago, that during the Model A production, engine parts were sorted according to weight, just what the sorting specs were, I don't know, but I would suspect the same thinking held during the T production. It was probably over-all weight, not like today when you send rods to be balanced, they are weight balanced at each end. The piston end is just up and down, but the crank end is in circular motion, and I would think, a big more critical.
Ken is right. I remember seeing an old newsreel video that showed pistons being weighed and separated into four groups. Then those pistons were moved as a group to engine assembly. I do not know if they were marked though.
A lot of original pistons were marked with from one to four center punch marks on the top of the piston. These were the weight grouping marks, not cylinder positions. I have pulled pistons out of several original engines over the years. All pistons marked alike.