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fredmeister fredmeister is offline
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Join Date: Oct 2002
Location: Baltimore, MD, USA
Posts: 2,184
Garage
Re-ringed my Alusils about 50k miles ago. Compression 120psi roughly all cylinders, taken ast week. No oil smoke even little on initial cold start. I think the reason for the lower compression numbers was the fact that they measured compresion ratios were in the average 7.9 or 8.0 to 1. Not the 8.5 to 1 specified by Mahle or Kolbenscmidt!
Anyway, I was working at Mahle at the time and had the test lab measure all pistons and cylinders to factory specs using the proper equipment. Al within tolerance range allowable. Some surface scratches on the piston skirts but no scuffing damage.
All I did was use steel wool and wet and dry sandpaper to the cylinder walls to break the glaze/clean up the surface then re-ringed with Goetze rings.
Seems great to date 5 years and 55000 miles later. Only disappointment is the lower than thought compression ratio.
Anyone thinnk 120psi compression is in the ballpark or is that a little low?
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1979 930 Turbo....3.4L, 7.5to1 comp, SC cams, B&B intercooler, Snow Perf water/meth injection, Rarlyl8 headers, Garret GTX turbo, 36mm ported intakes, Innovate Auxbox/LM-1, custom Manually Adjustable wastegate housing (0.8-1.1bar),--running 0.7bar max
---"When you're racing it's life! Anything else either before or after, is just waiting"
Old 12-10-2004, 08:20 AM
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