OP
fordcomanche
Member
- Joined
- Jun 6, 2009
- Messages
- 45
I was able to get some measurements on the cylinder wear from my machinist friend so thought I'd share them. The wear isnt too bad for 40 years since rebuild
The book listed bore spec as 3.900" and we measured the following:
I showed him the existing sleeve wall thickness and mentioned about the thin sleeves in the overbore kit and he thought it would still be best to just bore these sleeves to .020 over and put in new pistons/ring.
The crankshaft main journals were ground .020 under during the 1970 rebuild and were still close, with the rear journal showing the most wear:
Original STD Spec 2.4974-2.4988, (20 under spec 2.4774-2.4788)
Journals were measured at 2 positions, 90 deg apart and were measured at both ends of journal
Rod bearings were previously ground .010 under and also were still within spec.
The crank journals are smooth but do have some staining in the center of journals, so considering getting it polished
The camshaft itself had quite a bit of rust on it and although the journals look good and within spec, some of the lobes have some small pitting from the rust. Likewise a few of the valve tappets had some of this pitting on the surface riding the cam.
Please let me know how this motor condition compares to others that have undergone rebuild.
Thanks
The book listed bore spec as 3.900" and we measured the following:
Cylinder | Bottom of Bore (Inline) with no wear | Bottom of skirt area 1/2 way down bore (crosswise) | Upper Bore Area with Max Wear (Inline) | Upper Bore Area with Max Wear (crosswise) | Near top of bore in ridge ream area (Inline) | Near top of bore in ridge ream area (Crosswise) |
1 | 3.899" | 3.901 | 3.905 | 3.903 | 3.900 | 3.901 |
2 | 3.899" | 3.901 | 3.904 | 3.904 | 3.8995 | 3.900 |
3 | 3.900" | 3.902 | 3.902 | 3.902 | 3.8990 | 3.8990 |
4 | 3.8987" | 3.8999 | 3.906 | 3.902 | 3.8990 | 3.8990 |
I showed him the existing sleeve wall thickness and mentioned about the thin sleeves in the overbore kit and he thought it would still be best to just bore these sleeves to .020 over and put in new pistons/ring.
The crankshaft main journals were ground .020 under during the 1970 rebuild and were still close, with the rear journal showing the most wear:
Original STD Spec 2.4974-2.4988, (20 under spec 2.4774-2.4788)
Journals were measured at 2 positions, 90 deg apart and were measured at both ends of journal
Crank Bearing: | Horizontal Meas | Vertical Meas |
Front Journal | 2.4774/2.4775 | 2.4774/2.4775 |
Center Journal | 2.4775/2.4775 | 2.4775/2.4775 |
Rear Journal | 2.4772/2.4772 | 2.4772/2.4772 |
The crank journals are smooth but do have some staining in the center of journals, so considering getting it polished
The camshaft itself had quite a bit of rust on it and although the journals look good and within spec, some of the lobes have some small pitting from the rust. Likewise a few of the valve tappets had some of this pitting on the surface riding the cam.
Please let me know how this motor condition compares to others that have undergone rebuild.
Thanks