Tegheim - Home made 4 rotor Wolvo 142

[Rotary Evolution]

Originally Posted by Tegheim

I bought a bunch of new rotors. How do I comfirm that they are 9.7:1-compression?
I have weight them, but all the newer rotors have the same weight. The 28cc in the comb-chamber are kind of tricky to check, or?

take a caliper and a flat piece of metal, mic the metal and zero out the gauge. lay the strip over the pocket and measure the depth of just the pocket and it should be very close to 10.85mm in depth and have a machined relief(the deeper the pocket is, obviously the lower the compression is). this is the measured depth for the 9.7:1 rotors.

turbo rotors also have a T stamp embossed into the oil relief vein area facing the center iron, n/a rotors have no T stamp, just a I and II for front and rear(which accompany the T on turbo rotors).

that said, the quickest and easiest method is just check the oil galley in the rotor for the T stamp(or lack thereof in this case) and make sure the rotor has a machined pocket for the series 5.

if you somehow managed to get renesis rotors they're a little less conspicuous with their scallops and thick side seal lands.