Thruapole
Probationary Member
- 25
- 3
- Dec 23, 2004
-
Parsippany,
New Jersey
The same exact thing happened to my 4G64 over this past summer. The part that weirds me out is that the thrust surface was still fine, just like yours is. I chalked it up to either the crankshaft cracking, or the main cap bending (probably from detonation).
I bought a new crankshaft and bearings and upon reassembly found that there was .0025 oil clearance in main bearings #1,2,4,5 and .0005 in #3. I line honed the mains so all were at .0027-.0028 and reassembled with the new parts and it is running fine now. I never found out what came first, the crank cracking or the cap bending and closing up the bearing clearance.
I bought a new crankshaft and bearings and upon reassembly found that there was .0025 oil clearance in main bearings #1,2,4,5 and .0005 in #3. I line honed the mains so all were at .0027-.0028 and reassembled with the new parts and it is running fine now. I never found out what came first, the crank cracking or the cap bending and closing up the bearing clearance.
