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KTL KTL is offline
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Join Date: Sep 2000
Location: Frankfort IL USA
Posts: 16,210
Originally posted by ZAMIRZ
The 4G63 has crank-walk problems when you start upping the boost, but it's cheap and readily available so if you blow it up getting another one won't be that big of a deal.
Apparently, the factory had a bad run of crankshafts. The crankshafts were machined just slightly out of spec, and as a result the main center thrust bearing on the crankshaft wears prematurely. When this happens, the crankshaft will move or "walk" every time the clutch pedal is depressed. Some people have complained of difficulty in getting the car into gear (manual transmissions) and the diagnosis has been the same: a "walking" crankshaft. The crank can walk so much that it pushes the crank sprocket and the trigger plate forward and causing the trigger plate to come in contact with the crank sensor, thus breaking it. When broken, car won't run because ECU needs signal from crank sensor to know when to fire coil and run injectors!

Mostly a 1995+ 2nd generation motor problem. Something the factory is VERY aware of. Get a 1st generation 6-bolt to reduce the likelihood of that problem. Stronger bottom end too.
Kevin L
Present: '86 Carrera, '79 911SC widebody conversion rolling racecar shell
Past: '87 Carrera
Old 01-30-2004, 01:53 PM
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