alternator balancing

Is balancing the alternator a thing? The reason I ask is that I have had to add a couple of big washers under my 4" pulley for spacing, and want to make sure I'm not inducing an unnecessary vibration.

It does need to be balanced, but if the washers are a snug fit on the shaft (centered), it wouldn't worry me.

However... having played around with a lot of different automotive alternators, adapting them to a/c engines and to other auto engines, I'd look carefully at the retaining nut, to be sure it still has adequate 'bite' on the shaft threads. Many alternators don't leave a lot of wiggle room for anything other than 'stock' thickness pulleys.

FWIW,

Charlie

cheap hardware

Thanks Charlie. The 4" Summit pulley is about 3/16" thinner than the original, which is why I added 2 washers close to the alternator, and one close to the nut. There are plenty of threads.

The washers didn't seem like they had a lot of precision since they are cheap hardware store items, thought I'd check on the balancing.

Perhaps I should find a better source.

Find someone with a lathe and turn a pair of spacers out of aluminum, since the pulley is alum too. That way, they will fit the shaft perfectly and no worries about balance. Plus, you could fine-tune belt alignment through spacer thickness if desired.

Heinrich

When you are doing your prop balance you can see the alternator peak show up on the vibration spectrum. Make sure you do it on a balancer that can show you the full spectrum.
To find the peak just calculate the rpm from the size of the pulleys. Mine spins at 3.61 x engine rpm.