Hi Zeders
What have I started with my harmonic balancers, all I know is that BMW make one of the best harmonic balancer there is, that is why I use it. I ran the biggest heaviest Z one I could find on my Targa car in 98, it lasted three days, I rebuilt it, it lasted one more day before it disintegrated again and split the casting through the keyway. I put on another Cheepie, I finished the Targa carefully.
A month or so later at Sandown it buggered up to, but in the process I did the number one big end bearing on a relatively new motor, ( the other journals were perfect ) a direct result of the shaft harmonics shaking the guts out of the crank, I then built a BMW one, it has been on there since 98, and done two more Targa’s, and races ever since.
An L series revving to 6500 to 6800 RPM, a standard one will last almost forever, but if you accidentally, or deliberately go over 7000 RPM, they are finished, not to mention what you are doing to your engines internals. Since the new one I have still accidentally almost hit 8000 coming out of very wet hairpin corners in low or 2nd gear, and instant revs.
Ideally they should a flywheel on each end of the crank, so the BMW balancer is the next best thing, I make mine so big it clears the water pump pulley by only 4 mm. The further you get the balancer out from the crank, the more stable it makes the crank.
Some of you may have read that BRE fitted finned alloy sumps to there race cars in the 70’s for cooling, the harmonics were so bad through the block, that it sheared all the centre sump bolts on each side of the block, that gives you some idea of what's happening in your poor little Z engine at full works, and the power loss. I have proved it does the job, that’s why I build and sell them.
I also made and fitted an engine girdle, a 4 mm high tensile steel plate that covers the bottom of the block between the sump and the block to turn the engine block into a solid box instead of an upside down channel that can twist and wobble
The harmonic balancers by the way are $380 each, plus GST if applicable, and freight, depending on your post code.
Regards Len