|
Masseynut(Australia)
05-20-2008 05:45:43
|
|
Re: 175 blow-by in reply to JBMac, 05-20-2008 05:16:46
|
|
| |
Well now, there's a couple of questions here. Has the engine done a lot of work, or could it be just "glazed" from lack of hard work, or a heavy loading, for a period of time. The "blow-by" can be caused by both the reasons you have nominated. Excessive valve guide and/or valve stem wear can cause crank-case compression, remedied by lifting the head, and renewing either or both. Crankcase compression can also be caused by an insufficient seal between the compression rings, and the cylinder bores. This can occur at the same time that the oil control rings are functioning as they should. This often explains how an engine uses no oil, but has excessive crankcase pressure. If you are "pulling the head", I would get the cylinder head checked out, and, drop the sump and remove the piston assemblies. It's not a lot more work to do this. Check the bore for wear, remove a top compression ring, slip it into the bore, about an inch down from the top, and check the "gap". Ring gap for a "good" engine should be, as a rule, .003" for every inch of diameter of bore size. Anything greater than this will give you "crankcase compression" to a degree. Somethings to think about, regards, Evan.
|
|
|
