Posted by Daryl in Oz [58.178.194.38] on Monday, December 09, 2013 at 06:31:54 :
In Reply to: Piston/rings - what might I look for? posted by don in nh [96.61.72.163] on Sunday, December 08, 2013 at 22:53:01 :
Couple things come to mind - first, take an oil ring off the piston and put it in the bore, push it down with the piston about 1" to 1.5" and measure the end gap. Think you will find it's a bit out of spec, so new rings needed. Second, what is the condition of the valve faces? Should be clean and sharp edged, with a dull grey color where it contacts the valve seat, any doubt then you need a valve grind. When/if you pull a valve, you need to post a picture showing if there's any carbon build up on it, especially if there's build up on the stem - if so you need to check the valve to guide clearance. A lot of times when you get a hot engine leak down problem it's caused by valves. Can be too tight tappets caused by valves seating deeper due to wear, can be too tight clearance because the spec used wasn't for that particular engine - there are several clearances listed for different models and configurations, also the mil spec is different to the civvy spec.
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