sigmaturbo - Page: 74 of 75

The shaft should have slipped through nicely. The ‘top hat’ as its called by Garrett should be inserted into the carbon seal as shown. Push it home and hold the assembly carefully as you tighten the four bolts that hold the backing plate in place. This will ensure that that backing plate is well centred and give it a fair chance of sliding home easier. After this step the shaft should spin freely and be removable without difficulty. The top
hat should also be free and easily removable.

The shaft in and the turbine on. Tighten the nut up while taking care not to load the shaft in any way that could bend or throw it off balance. I used a screw driver with socket attachment on the exhaust end and a small spanner on the inlet end. Make sure the marks on the nut, the shaft and the turbine on the inlet end line up to get
that perfect balance and tightness. The inlet housing goes back on simple enough. With the o ring in place just slip it over as shown and bolt in place. Leave it loose though for later as you’ll need to turn it into the
right place to locate properly with the crossover pipe.

Bolt holes have been milled out on a milling table and re tapped with 8x1.25mm threads. The new high tensile bolts supplied threaded right in without problems and you’ll have noticed the collar that came off the old one is no longer required. Now replaced by 3 small clamp plates. Before I finished though I attacked that scaling and rust pitting with a die grinder to gently improve the surfaces. I checked by putting the exhaust housing on and tightening up and found that the area was actually rubbing on the turbine fins when it turned. NUTS… Here’s
some after shots. Needless to say the exhaust housing is beyond its lifetime but this will get a little more time out of an otherwise irreplaceable part.