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Post by new2rotary on Jan 2, 2011 21:41:25 GMT -5
I was wondering what the compression on a 75 re5 should be
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Post by wayne on Jan 3, 2011 0:01:41 GMT -5
Very variable. About the best that you're going to see is around the 140 psi mark.
I have graphs for the same engine from first service: 138, then at 42,000 kilometres: 134.5, and at 64,000 kilometres: 116.
Another new engine with 3,000 klm: 140.6.
My engine which is adequate two up with luggage but lacks a bit of grunt: 131.
You can get an idea by just putting in a standard piston engine compression tester but you won't get the correct figure unless you use the proper tester with a trace. I'll put up some trace comparisons and make a link or post it here.
Wayne
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Post by wayne on Jan 3, 2011 0:19:46 GMT -5
Here are some compression traces: Most important: Trace 2 and 3 are misaligned at the bottom. The trace starts below the Zero line. To correctly read these, you must mentally move the whole trace up. For example, "Wayne's Trace" is actually a peak compression of about 131 when the alignment is corrected. Also note that the traces not only show peak compression, but each peak is a single chamber. So you are not only looking at overall compression, but how even the trace is. Wayne
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Post by steveuk on Jan 3, 2011 8:02:38 GMT -5
My compression on my latest project is only 4.5 bar and so will not start, but while its been standing its getting coolant in the bottom of the housing which is a possible place where compression could leak past the water jacket o rings.
If i can find some of the long proper unit tools i want to have a go at repairing it.
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