GSTwithPSI
Well-known member
I disassembled my motor and took some measurements for the rebuild. I have a used crankshaft that I'm planning to put in the car, and took some measurements just to verify it is good. The strange thing is that the measurements I took on the new crank are identical to that of the old one. Simply, the smoked crank that's in the car right now measures out to be identical to the used one I have. That wouldn't be strange normally, but both cranks are identically under factory specs. Here are the measurements:
Old crank (smoked)
Main Journals
1= 2.234"
2= 2.234"
3= 2.235"
4= 2.234"
5= 2.235"
Rod Journals
1= 1.762"
2= 1.762"
3= 1.762"
4= 1.767" (This was the burned journal)
Newer crank
Main Journals
1= 2.235"
2= 2.234"
3= 2.234"
4= 2.234"
5= 2.234"
Rod Journals
1= 1.762"
2= 1.762"
3= 1.763"
4= 1.762"
Rod Journal OD spec = 1.7709-1.7715
Main Journal OD spec = 2.2433-2.2439
It looks to me that BOTH cranks have been cut down .010" on both the main and rod journals. It's just blowing my mind that both cranks are measuring out under specs, but are measuring out exactly the same? I know my mics are reading right, and I double checked each mic measurement with my dial caliper just to be sure. What are the chances of that? Additionally, the bearings I pulled out of both the main and rod journals say .25 on them. I thought this was a standard bearing, but now I'm not so sure. Does .25 usually identify a standard bearing? Any help or input is greatly appreciated.
Here is a pic of the bearings.
The main bearing is engraved: M1-1085 .25 NDC
The rod bearing is engraved: C1-1085 .25 NDC
Old crank (smoked)
Main Journals
1= 2.234"
2= 2.234"
3= 2.235"
4= 2.234"
5= 2.235"
Rod Journals
1= 1.762"
2= 1.762"
3= 1.762"
4= 1.767" (This was the burned journal)
Newer crank
Main Journals
1= 2.235"
2= 2.234"
3= 2.234"
4= 2.234"
5= 2.234"
Rod Journals
1= 1.762"
2= 1.762"
3= 1.763"
4= 1.762"
Rod Journal OD spec = 1.7709-1.7715
Main Journal OD spec = 2.2433-2.2439
It looks to me that BOTH cranks have been cut down .010" on both the main and rod journals. It's just blowing my mind that both cranks are measuring out under specs, but are measuring out exactly the same? I know my mics are reading right, and I double checked each mic measurement with my dial caliper just to be sure. What are the chances of that? Additionally, the bearings I pulled out of both the main and rod journals say .25 on them. I thought this was a standard bearing, but now I'm not so sure. Does .25 usually identify a standard bearing? Any help or input is greatly appreciated.
Here is a pic of the bearings.
The main bearing is engraved: M1-1085 .25 NDC
The rod bearing is engraved: C1-1085 .25 NDC