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bought a 521 stroker kit from CNC motorsports. has 4.3" stroke cast eagle crank, eagle forged Hbeam rods with ARP capscrew bolts, mahle flat tops. clevit 77 rod and main bearings.
tq specs for the eagle rod ARP capscrew bolts are 63ftlbs, also the recomended rod bolt stretch is .0059-.0063". now my tq wrench is a cheap one since its rarely used (ive only built 2 motors) but the 1/2" drive tq wrench is less than 1yr old from harbor freight. my dads rod bolt stretch gauge is from summit and is the summit brand, never used and less than 2 yrs old.
so heres the issue:
I took the free length of the rod bolt (out of the rod) with .200" preload on the rod bolt stretch gauge. I then zero'd the gauge out (yes the rod bolt dimple/holes were used and lined up). covered the rod bolts with ARP fastner lube and screwed them in by hand. I then used the tq wrench on them and tq'd them to the recomended 63 ftlbs. I then took the rod bolt stretch gauge and with a steady hand saw only .004-.005" on the gauge! I then proceded to tq the bolts till they reached the .006" mark on the gauge. I then checked this with the tq wrench and found that they were in the 80-110ftlbs range! how is this possible? is the tq wrench off that much?
Also each rod bolt used a different tq rating, some only needed 80, some needed 95, 100, 110ftlbs, and each bolt on the same rod got different tq ratings. This was so each bolt had a stretch of .006".
what should i do?
also i tested the rod bearing clearance with a plastigauge and with the 63ftlbs with the tq wrench i saw .0015" clearance which is alil tight. but now that ive increased the tq on th bolts to 80-110ftlbs how is this going to affect the bearing clearances?
tq specs for the eagle rod ARP capscrew bolts are 63ftlbs, also the recomended rod bolt stretch is .0059-.0063". now my tq wrench is a cheap one since its rarely used (ive only built 2 motors) but the 1/2" drive tq wrench is less than 1yr old from harbor freight. my dads rod bolt stretch gauge is from summit and is the summit brand, never used and less than 2 yrs old.
so heres the issue:
I took the free length of the rod bolt (out of the rod) with .200" preload on the rod bolt stretch gauge. I then zero'd the gauge out (yes the rod bolt dimple/holes were used and lined up). covered the rod bolts with ARP fastner lube and screwed them in by hand. I then used the tq wrench on them and tq'd them to the recomended 63 ftlbs. I then took the rod bolt stretch gauge and with a steady hand saw only .004-.005" on the gauge! I then proceded to tq the bolts till they reached the .006" mark on the gauge. I then checked this with the tq wrench and found that they were in the 80-110ftlbs range! how is this possible? is the tq wrench off that much?
Also each rod bolt used a different tq rating, some only needed 80, some needed 95, 100, 110ftlbs, and each bolt on the same rod got different tq ratings. This was so each bolt had a stretch of .006".
what should i do?
also i tested the rod bearing clearance with a plastigauge and with the 63ftlbs with the tq wrench i saw .0015" clearance which is alil tight. but now that ive increased the tq on th bolts to 80-110ftlbs how is this going to affect the bearing clearances?