turbota440
Member
- Joined
- Apr 13, 2007
Rod bolts and bearings
While converting to a roller cam and I needed to pull the heads for guide clearance I decided to check the bearings. There was no engine damage and the previous cam was just starting to show some lobe wear on two lobes. Engine was rebuilt about 55k miles ago at about 100k miles on the original motor. With at total of 150k total miles on the engine now. On rebuild I used factory .030 over pistons and reused the sps rod bolts torqued to 40 lbs ft. on reconditioned original rods.
Bearings used in the rebuild were Clevite 960 mains and Clevite 1228 rod bearings.
Clearances were checked at 1.5 to 2 thousands clearance. Engine ran well and very quiet. Front cover was massaged and always showed good oil pressure.
Looking at the bearings in the engine now shows
Some of the rod bearings show copper on top half only. I assume detonation. Bottom half of same rod are very good almost no wear showing.
Mains are in good condition showing very little wear. Thinking of replacing with new 960 P just because I'm here.
Questions are:
1. Should I use the wider rod bearings Fed Mogul 3755apa or maybe Clevite ??
2. With 150k miles on Rod bolts I want to replace with GM replacement bolt 25531956. Is this an SPS bolt and of equal quality to original? Reason is that I don't want to pull the rods out or rebalance the assembly.
Primarily 99% street car weekend toy now. When raced before was a 11.7 quarter mile car.
While converting to a roller cam and I needed to pull the heads for guide clearance I decided to check the bearings. There was no engine damage and the previous cam was just starting to show some lobe wear on two lobes. Engine was rebuilt about 55k miles ago at about 100k miles on the original motor. With at total of 150k total miles on the engine now. On rebuild I used factory .030 over pistons and reused the sps rod bolts torqued to 40 lbs ft. on reconditioned original rods.
Bearings used in the rebuild were Clevite 960 mains and Clevite 1228 rod bearings.
Clearances were checked at 1.5 to 2 thousands clearance. Engine ran well and very quiet. Front cover was massaged and always showed good oil pressure.
Looking at the bearings in the engine now shows
Some of the rod bearings show copper on top half only. I assume detonation. Bottom half of same rod are very good almost no wear showing.
Mains are in good condition showing very little wear. Thinking of replacing with new 960 P just because I'm here.
Questions are:
1. Should I use the wider rod bearings Fed Mogul 3755apa or maybe Clevite ??
2. With 150k miles on Rod bolts I want to replace with GM replacement bolt 25531956. Is this an SPS bolt and of equal quality to original? Reason is that I don't want to pull the rods out or rebalance the assembly.
Primarily 99% street car weekend toy now. When raced before was a 11.7 quarter mile car.
