I am re-building a Mitsubishi 2.6 L engine (Caravan 84). After installing the main bearings and finding all appeared well ? the crank turned without effort, I started to install rod bearings, trying #1 and #3 pistons. The rotational resistance torque increased by over 100 ft.lb with rod bearing #1 tightened to spec (34 ft.lb) and that of #3 to 55 ft.lb with rod bearing tightenened to spec. This was without any rings installed so that the increased rotational resistance is only due to the bearing. The diameter of the crankshaft and the clearance as measured with Pastigauge (deformable plastic gauge) are:
Piston Diam(in) Clearance(Thou) Clearance Spec (Thou) (Haynes)
1 2.057 .001 .0008 to .0028
2 2.056
3 2.056 .00125
4 2.056
What am I doing wrong? Thanks for any light you can shed.
Notes
- The crankshaft was ground to .030 (main and rod)
- The main bearings are labelled .030
- The rod bearings are labelled .75 (I assume mm, the equivalent of .030 thou)
- The bearing shells are located correctly with the tabs in the slots.
- The Plastigauge was used properly, w/o oil film.
- The bearing were coated with oil for the turning test