Ender-3 1cm Z-motor lower spacer

Keeping dual-Z motors in sync over time is a pain.
Print 2 of these and use along with Supavitax's side spacer to lift the motors up by about 1 cm. This provides the necessary space above the printer to add geared pulleys and a belt to keep the two rods in sync.

Just add:
Any dual Z-axis kit which includes upper guides with bearings
replacement screws for the motor mount + T nuts (Don't ask me what size, they were in my bag of spare parts that came with the machine when it was new)
2 toothed pullies: 8mm bore, 20 tooth, 6mm belt
1 belt: 6 mm x 618 mm closed, 2mm pitch (618-2gt-6)
1 tensioner: I added an aftermarket adjustable tensioner to the x axis and reused the stock one here.
Optional:
Flex coupler for one or both of the Z-axis motors (5mm to 8mm)

Then align, align, align, and once you get everything working, don't break it. :)
This has been working well for a few weeks now on my sister's printer.
Fingers crossed this just keeps working for her.