Capacitors

As far as value goes, it's hard to tell. What you have are not really common capacitors. It really would help if you knew what type of motor they were used with.

From there, you could find a real value.

Most of the time if you replaced a cap you are going to put in a new one and not a used one because they don't cost a whole lot and you wouldn't want the cap to fail again soon unless they are expensive.

The second picture seems to sell on ebay...but they all may sell well. You just never know. I'm sure you could expose these to more potential purchasers if you knew what they were from. 1000 volts, 635 volts, are just uncommon, it's high voltage for a motor.

Aerovox Capacitor 1000 Volt 13 MFD Oil Fill Capacitor No PCB Priced for 2 | eBay

here is one of them i was able to identify, none have sold though, im guessing you could put them on ebay and get $30 each but you might be sitting on them a very long time before they sell:

Ronken 86C81136K50 Capacitor | eBay

car audio caps are 12volt and normally function between 10.5-18 volts. amperage i am not sure of off the top of my head. 0.5 farad is the entry level size and 48 farad was the biggest i have seen made for car audio. the farad amount should match the output or be higher than the connected amp. 500 watts = 0.5 farad. 1800 watts = 1.8 farad or next closest (2 or 2.5 farad). i ran a 4.5 farad cap with only 2000 watts. i have also ran backwards and had a 0.5 farad on a 1000 watt amp and it simply is not enough to do its job so you are better off not using one at all as it chokes the voltage because it limits what can be drawn through.

i will tell you this much; most car audio caps are not necessarily cheap but i will never put a cap not specifically made for car audio on an amp. the caps are much cheaper than an amp.

a cheap cap is $15-25. they can cost a couple hundred dependant on size and brand.

amps on the other hand are cheap at $40-100 and can cost thousands on high end.

when wired, the cap runs between battery and amplifier. you tell me what is gonna be the first part to go...? my point is caps are too cheap to risk cooking an amp or any other part in the system. use the caps for what they are speced for not just random placement. you will ruin something pretty fast otherwise and maybe even start a fire.

The cap is put in line to eliminate the "sagging" of the power line voltage. When the bass thumps hard it'll pull hard on the voltage and cause it to sag or go below 12/13 volt. The cap acts like a quick battery and gives a shot of juice in the line to bring the voltage back up and eliminate the sagging.

A car audio power cap works by storing large amounts of electrical power which it can then deliver to power hungry components when called upon to do so. They have an advantage over typical lead acid storage batteries because they have very low internal resistance. This allows them to deliver large amounts of power (current) very quickly. Much faster than a car's charging system can deliver that same amount of current.

Thanks to car audio online