911sc compression

[Aussie]

Does anyone know what the compression should be for a 1978 911 SC 3.0 ltr?

[88 Club Sport]

Check out the following thread..... http://forums.pelicanparts.com/porsche-911-technical-forum/139414-questions-about-3-2-sc-post1080033.html#post1080033



Craig

[juanbenae]

mine when ppi'ed with 64k on the clock was between 164-168 across all 6 holes. from what i understand consistancy from cylinder to cylinder is nearly as important as the #'s themselves.

[rdane]

My '79 went from 160/165 @ 160K to 150 @ 174K to 145 in all 6 @ 179K.
I suspect some of that difference was human and mechnical error.
Leak down @ 195K miles was between 6 and 12% and 183hp at the rear wheels. So the engine was still very strong even at 195K miles. Consistancy is the key as k911sc mentioned.

Not that you asked but I would look at leak down, oil consumption, compression and a dyno run as a whole to see what shape your engine is in.

[Superman]

Agreed. Compression levels are among the least important. Seems to vary according to the tool used, heat of the engine, etc. Consistency from one cylinder to another is FAR more important. That information, along with a leakdown test and monitoring of things like oil consumption, startup smoke, valve adjust findings, etc. can give a good picture of engine health.