Why not use washers instead?

[V8INtheZ]

I have been reading and reading about the 4x4 toyota swap for weeks now. I think I have read every thread related to the swap. There are a few post warning against using washers in place of machined spacers, but no reason why.

 

I want to use the Z31 5 lug rotor/hub with s12w calipers/pads, I know I need a spacer, and I know about what size I need for my early 260z.

 

Can one of you guys explain the risk in using washers instead? I know there are a handful of guys using washers on their cars, the only thing I can think of is balance issues caused by the washers.

[blueovalz]

I personally would not use a set of washers for several reasons:

1) A stack of washers allows more movement over a properly designed spacer should the bolts holding the rotor into place become loose (would or should they ever do this is another issue).

 

2) This one is most important to me. I've taken washers and measured their thickness, and even SAE washers sometimes show some variance in thickness. Unless you have measured the stack of washers to ensure each bolt has an identical value for the width of the washer stack, you're placing some degree of runout into the rotor when it all gets installed.

 

3) The spacer allows full contact between the rotor and the hub when it's all assembled. Washers offer a smaller contact area between the two. Almost like you would be "cantilevering" the rotor out from the hub.

[V8INtheZ]

Runout, now thats a good reason not to use washers. Okie doke, thanks very much for the help Blue. I will order some spacers from Ross today.