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30 over block pure stock rules tanked block checked for cracks speed-pro 6 inch dome hypers, rod clearance .002 mains .0015 ran motor on run in stand set timing at 34 degrees @ 3000 run for about 2 hours and it had 95lbs oil pressure cold came down to 75 cold 160 degrees water temp.put in in the car ran it about 5 laps and it broke up real bad.brought it in checked timing timing was then 49 degrees so we locked dist and went back out motor developed a knock so shut it off ,removed motor ,wix oil filter felt like about 5 lbs heavy pulled pan checked rod bearings they all had a scratch in them .pulled mains and down to copper.i put a magnet in the pan and the left over oil was magnetic? the new piston skirts look like they were sanded with 80 grit and most all the coating is gone .003-.004 clearance on piston skirts when put together. not sure what happened.it feels like a fine sand in the oil pan piston coating? i found no other part of the engine worn other than scratches in crank . could the bearings have been washed with too much oil pressure or timing hammered out mains?
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Setting your timing at 3000 RPM is alright if your max RPM is 3000 out on the track, If you max RPM out on the track is 7000 roll the throttle up that far and make sure its where it has to be at that RPm and don't use a dial back light!!
Sound like a very dirty build, Not plugging the oil filter bypass will allow unfiltered oil to get to the bearings more so where your running a HV pump and maybe heavy oil.
If your block has the press in plug up near the top if the head on the left side and it was not removed that could be a problem as there is no way to clean that oil galley with out plulling that plug out.
I have seen engines come in the shop with that tight of bearing clearances and not seen and bearing issues.
Also was the block aligned honed?? plate honed?? what did they use for a hone to hone the cylinders with and what stones?? Was the block even decked???
Hyper pistons should not be used in any performance engine as we have seen guys try that with not very good results!!!
Also make sure the plug is under the rear main cap!!
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