ZA50 Transmission and Crankshaft Shimming

Shims

Shims for the transmission and crankshaft can be found on McMaster-Carr or hand made with sand paper, time and a flat surface. Stock numbers for mcmaster carr are below.

clutch shaft diagram

 Clutch shaft:

• 99432A364 - 0.127mm - Shim For Die Punches, .005" Thick, 3/4" Od, .595" Id 
• 99432A366 - 0.381mm - Shim for Die Punches .015" Thick, 3/4" OD, .595" ID, packs of 10
• 99432A449 - 0.635mm - Shim for Die Punches .032" Thick, .595" ID, 3/4" OD, packs of 10

Gearshaft Diagram

Generally, you'll use one 1.5mm shim to take up a majority of the space and then use the .1mm shims for final adjustment.

Gear shaft:

• 98055A117 - Metric Spring Steel Shim - Din 988, 0.1mm Thick, 10mm Id, 16mm Od
• 98089A123 - Metric 18-8 Stainless Steel Shim, 1.5mm Thick, 10mm Id, 16mm Od

Crankshaft Diagram

Crankshaft L17 side:

• 98089A230 - Metric 18-8 Stainless Steel Shim .1mm Thick, 18mm ID, 25mm OD, packs of 25
• 98089A270 - Metric 18-8 Stainless Steel Shim .2mm Thick, 18mm ID, 25mm OD, packs of 25

Crankshaft E20 side:

• 90214A135 - Metric 316 Stainless Steel Shim 0.1mm Thick, 20mm ID, 28mm OD, packs of 5
• 90214A236 - Metric 316 Stainless Steel Shim 0.2mm Thick, 20mm ID, 28mm OD, packs of 5

The only shims not available from McMaster are the 0.005mm shims for the L17 side - these are for the time being available from treatland.tv

End play float adjustment can also be done on the crankshaft by cutting multiple or individual case gaskets of differing thicknesses than stock. Measure your end play float and compensate with the appropriate paper thickness. When you're ready to cut your own gasket, us Mustachio's gasket template. Make sure to not scale the print to page size when you print and print it in actual size. You can download the case gasket template here. Stock gasket thicknesses are in the range of 0.2-0.25mm. The material I usually use ends up being a compressed thickness of 0.22mm. Card-stocks will get you differing thicknesses.

Tools

The only tool you really need to properly build these motors is the crankshaft shimming tool - everything else can be done with plastigauge or calipers and a straight edge. I highly suggest shipping your motor off with the gasket you intend to use to someone with the tool before installing your other bearing. Removing the bearings to change the shimming is difficult to do without damaging the bearing. Feel free to contact me and ship your motor to me.

The transmission shim tool is in my opinion not necessary with the use of  plastigauge which is available at any automotive store. Place a small bit of the plastigauge between two of the shims or the shim and bearing and use the gauge to measure the gap. I usually place two pieces 180* out or even four pieces 90* out to make sure that equal pressure is applied to the plastigauge. Make sure to install the gasket and torque all of your case cover bolts down to spec where you will be running it, then and only then, remove your case cover and measure the plastigauge. Adjust your shims according to your readings and re-measure. Continue until your readings are reasonable. I usually shoot for tighter tolerances the more power I'm putting through, but as long as you're within specs, you're good.