LA 360 - 0.030" Undersize Main Bearing Clearance Questions
Seeing a decent amount of views with no responses. In an attempt to provide as much info as possible, I might have accidentally provided too much info and made it a PITA for anyone to read/respond. Main post revised just in case.
The interesting part to me is my main housing bore diameter vs the desired spec and the the main journal diameter vs the desired spec. It was difficult to actually find the OEM spec for a main housing bore for a 360. Mahle references a range of 3.0025 in. - 3.0030 in. in their parts catalog. I found the same specs on page 60 of my "How to Rebuild Small Block Mopar Engines" book (the early edition that is LA specific):
I searched my FSM PDF and couldn't find this documented anywhere in there. The thing I find interesting about my bearing clearances is that my block measured 0.0020 in. - 0.0025 in. above the main housing bore spec. I don't do this stuff professionally, so I could be wrong, but even with the main shaft diameter of my crank being 0.0008 in. - 0.0011 in. larger than the upper end of the spec, I would expect a bit looser bearing clearances. Below is a table of the differences in main housing bore diameter and the major shaft diameter for each main for my 360:
When compared to the loose end of the acceptable specs listed by Mahle (3.0030 in. main housing bore diameter - 2.7795 in. shaft diameter = 0.2235 in. delta), mains 1-4 for my 360 all have a larger delta and main #5 is just slightly (0.0001) smaller. Shouldn't that result in a larger bearing clearance? What am I missing here?
Seeing a decent amount of views with no responses. In an attempt to provide as much info as possible, I might have accidentally provided too much info and made it a PITA for anyone to read/respond. Main post revised just in case.
The interesting part to me is my main housing bore diameter vs the desired spec and the the main journal diameter vs the desired spec. It was difficult to actually find the OEM spec for a main housing bore for a 360. Mahle references a range of 3.0025 in. - 3.0030 in. in their parts catalog. I found the same specs on page 60 of my "How to Rebuild Small Block Mopar Engines" book (the early edition that is LA specific):
I searched my FSM PDF and couldn't find this documented anywhere in there. The thing I find interesting about my bearing clearances is that my block measured 0.0020 in. - 0.0025 in. above the main housing bore spec. I don't do this stuff professionally, so I could be wrong, but even with the main shaft diameter of my crank being 0.0008 in. - 0.0011 in. larger than the upper end of the spec, I would expect a bit looser bearing clearances. Below is a table of the differences in main housing bore diameter and the major shaft diameter for each main for my 360:
When compared to the loose end of the acceptable specs listed by Mahle (3.0030 in. main housing bore diameter - 2.7795 in. shaft diameter = 0.2235 in. delta), mains 1-4 for my 360 all have a larger delta and main #5 is just slightly (0.0001) smaller. Shouldn't that result in a larger bearing clearance? What am I missing here?