Indy says no need for Leak Down, just Diagnostics?
05-22-2010, 03:29 PM
#16
Race Director
I agree the engine should throw a CEL if one cyl is weak. We used to call this a cylinder balance test and we did it by disconnecting one spark at a time and looking at rpm drop. Problem is it doesn,t indicate an evenly worn engine with all cylinders down.A condition sometimes found on high mile engines, a compression and leakdown would do that. I would not bother with a leakdown if the engine has under 75000 mi and no CEL.
Generally a worn engine will rev ok it just doesn't have the grunt at low to mid range, at higher engine loads, cause the cylinders of course don't have the compression they once did.
However, worn out engines appear to be rare. Most often before the engine wears out it develops a ticking valve lifter, or a flat lobe on a cam shaft, or excessive camchain noise or of course more serious problems.
Plus I can testify that if properly cared for these engines can accumulate some big miles with no apparent ill effects. My 02 Boxster has just over 231K miles on its original engine (and clutch) and the engine still runs very well, pulls strong right off of idle and mid-range is strong too. Plus it revs to redline when I have the guts to rev it that high.
Sincerely,
Macster.
