Quote:
Originally Posted by BRENT in 10-uh-C
Dave, did you actually check the balance of the Burlington prior to mating your flywheels? Also, was the rest of the rotating assy. statically balanced and then dynamically matched?
FWIW, in times past I have also experienced some vibrations on engines that used a Burlington crank and just took the assumption they were balanced at the factory. I later learned from those early experiences that I should assume nothing. I now balance three different times, first the crankshaft, next the flywheel & the crankshaft as an assembly, -and finally the pressure plate mounted to the balanced flywheel/crank assy. Since using SCAT product exclusively, my balancing time and use of heavy metal has diminished substantially. I think that probably has more to do with the design differences between the two cranks.
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Brent,
I did the same balancing as you. Burlington crankshaft first, then add lightened flywheel to crank and balance making the adjustment to the flywheel then add clutch cover and balance again only modifying the clutch cover.
Since this problem, I have all of my reground cranks checked and adjusted as needed as part of the process before I will use them. I have 10-15 cranks processed at a time to get a pricing advantage from both the grind shop and the balancing shop. I usually have 6 flywheels completed at the same time also. Touring engines often require a trip back to the balancing shop if the customer wants a different weight on his flywheel than what it was balanced with. I cannot keep all combinations in stock but also cannot be running back to the balancer for every engine. Most people are receptive to following my advice of a good combination.
FWIW: Over the past couple years, I built up a B block with a new Roof overhead valve head. I tested it about three months ago in a new (to me) touring car I am building and I was feeling some vibration or extreme pulse at a load and rpm I need to drive in. I have ordered a "Rattler" light Model A flywheel from Vibration Free, LTD in England. I also ordered a dampened front pulley from Mr. Horn. I will put both of them on the engine and re-install the engine late this winter and road test it in the spring. I think the flame front is traveling too fast in the combustion chamber causing the torsional pulse. Hopefully, the dampers will calm the beast. I also plan to change the valve timing by four degrees to bring the power band down in rpms. I have all kinds of power at 3500 rpm (115 hp) but somewhat lower than I would expect from 1800 to 2600 rpm (40 -65 hp). I am trying to reach 75 - 80 hp at 2600 rpm...I am not very confident it is possible.
I plan to report my results when completed.
Good Day!