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Old 10-22-2013, 05:45 PM   #26 (permalink)
BGTV8
A True Z Fanatic
 
Join Date: Dec 2009
Location: 03350 Australia
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Drives: 09 Nissan 370Z M6
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For guys running high clamping force clutches - beware the implications for the thrust bearing on the crankshaft.

A 1200kg clutch implies you need to overcome 1200kg force with your leg leg pressing on the clutch pedal. the hydraulics will give you the leverage to do that, BUT you are still effectively trying to push the crankshaft out the front of the engine with 1200kg force.

This is absolutely going to accelerate the wear on the thrust bearing which has only been spec'd by Nissan for the OEM clutch clamping load.

Expect to see the thrust bearing ("washer") suffer accelerated wear as a consequence.

For most of us, this won't see the light of day as these typically have a life of 200,000klics, BUT wear is unlikely to be linearly proportional. In my race engine, we suffered oval bore wear after 4 seasons (with a SACHS twin-plate solid centre 1250Kg clamp-load) as a consequence of premature thrust washer wear). As a conseqeucne, we tear down the engine every season and replace main/big-end bearings and thrust face washer as a matter of course.

The consequences of excessive crank end-float caused by a high-clamping load clutch can extend to side loads on rods with asymettric wear on big-end and small-end bearings, oval wear in the bore, side wear on pistons in truly excessive cases - usually asscoated with hi-mileage engines used as DD with hi-clamping load clutch.

We always need to remember that an engine is a "complete system" and altering one component really requires thinking about the system as a total.

RB
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