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Join Date: Jan 2011
Location: Smack in the middle of Illinois
Thanked 283 Times in 278 Posts
Your loss of compression was not due to the rings - I would have done a cylinder leak down before taking it back apart
That being said, Why didn't you have the shop that bored the cylinder set the ring end gap? I bore cylinders and typically set the clearance at .0015" unless the owner says he's going to race it, then I set the clearance at .002" - and, yes your ring end gap is within spec for an 85 mm bore - if you check the papers that came with the Wiseco piston, for a bore of 87 mm (3.425") the top ring is correct at .0137" and the second ring is correct at .0171", but for high performance engines, the top ring is correct at .0154" and second at .0188" and for extra high performance (using a turbo or Nitrous , the top ring end gap would be set at .0171 and the second ring at .0188.
Yes, a Wiseco piston has to have Wiseco rings. No, you can't get 88 mm rings and file them for proper end gap in an 87 mm bore - the tension of the rings will be too great and the rings will press into the cylinder wall too hard.
The questions I would like answered is; how was the engine run during the first two minutes? Idle only, moderate throttle 1st, 2nd and 3rd gear, wide open throttle and were the rings installed right side up? Although you had the engine bored, did you do anything else? Did you use the 10:1 or 11:1 compression ratio piston? High lift cam? What was the clearance between the piston crown and the valves?
I will guess the problem was the cam jumped time and you bent the intake valves.