Quote:
Originally Posted by sjf911
I was dry fitting my crank and new Glyco main bearings today to measure bearing clearance. I am fitting a used 3.2L crank with standard mains confirmed to my 3.0 case. Using a new set of Glyco bearings from PP I came up with 0.08-0.085mm clearance consistently with both plastigauge and bore gauge. When I swapped my old bearings which have 125K miles back in, I got 0.055-0.06mm clearance. I measured the old bearing shell thickness versus the new and get over 0.0003 inch difference.
So, my old bearings measure in tolerance and my new ones don't. What are my options? Can the new bearings be coated up to standard? Should I source alternate bearings such as an official Porsche set from the local dealer?
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Steve, co-incidentally, Chris Carroll @ TurboKraft has today posted his findings on an engine he's building for Schnele, over in the 930 Super & Turbo Charging forum....he's also found problems with Glyco's, but on the rods.
Have a look on post #55 on p3 of my build thread (linked below)...I've had exactly the same issue as you on the mains, using Glyco's (although my rod shells are ok). I was able to swap them for some original Porsche items. I did exactly the same as you, retrieved and cleaned the old shells (84k miles old) and had far better clearances....the Glyco's put everything out of Porsche tolerance straight away!
Can't remember how much thickness a coating onto new shells will add, but was an option I would have taken had I not had an easy fix solution available to me.
Cheers
Spencer.