Reply To: 1955 QD 16 Rod Knock/Piston Upgrade Question

[Jeff Barsch]

Sooo, I’ve run into a bit of an issue.  When I split the 1955 case the rod knock was worse than I thought, and the upper cylinder had a large score.  After some honing I have it usable but the end gap on the rings is at .020 and the manual lists a top limit at .017.  The lower cylinder is at .016 so just in spec.

The question is could I modify the 1961 block to work on the 1955 motor.  It looks like I need to plug the thermostat holes on the block, and drill one new cooling hole.  I need to reuse the 1955 head but it looks like the holes line up as do the holes on the exhaust leg.  Everything else looks like it will line up (see pdf attached below with notes and photos).  The 1961 cylinders are in great shape and well below the upper end gap limit. Is there anything else I am overlooking? It looks like the starter mounts will bolt on and the intake bolts also match up.

If this works, I need to get three broken exhaust bolts out add a little green paint and I hopefully have a great runner.

 

I appreciate any insights.

 

Regards,

Jeff

1954 Evinrude 7.5 HP
1954 Evinrude 15 HP
1954 Gale 12 HP
1955 Johnson 10 HP
1956 Johnson 10 HP
1956 Gale 12 HP
1956 Evinrude 5.5 HP
1957 Johnson Golden Javelin 35
1958 Johnson 7.5
1960 Evinrude 18 HP
1973 Johnson 6 HP