Merc V6 History

[powerabout]

I was told by a Mercury rep some 30 years ago it was just what you said. Machine-Freeze- Snap with a cone, found a video that might be what is done today?

https://www.youtube.com/watch?v=QlVrDJBiqd4

Cant see that working for a roller as you have the damaged line where the laser cut it.

[bernie]

[QUOTE=powerabout;3012283]Cant see that working for a roller as you have the damaged line where the laser cut it.

Mercury used, and probably still does, a cracking process using a shallow vee notch on the rod thrust face and small drill holes thru the cap side to side. It has been 40 years since I was in manufacturing and don't remember the correct steps, but the crack did not follow a straight line like that laser video, and went back together with the micro grain lumps and bumbs realigning, then the rod was finish ground and honed - you would not see the crack after those operations. rckid74 hopefully remembers the individual steps better than I do.

[rckid74]

[QUOTE=bernie;3012296]

Cant see that working for a roller as you have the damaged line where the laser cut it.

Mercury used, and probably still does, a cracking process using a shallow vee notch on the rod thrust face and small drill holes thru the cap side to side. It has been 40 years since I was in manufacturing and don't remember the correct steps, but the crack did not follow a straight line like that laser video, and went back together with the micro grain lumps and bumbs realigning, then the rod was finish ground and honed - you would not see the crack after those operations. rckid74 hopefully remembers the individual steps better than I do.

The rod shown in that video is for a 4-stroke engine so would be used with a plain bearing not rollers. If you tried to run rollers over that notch across the bearing surface, you'd have instant failure! I was involved in Mercury's development of the cracked rod but don't remember a lot about it. It's pretty much as you say Bernie. You have to harden all the material in the crack zone, hense the drilled holes to allow the carburizing into the interior of the section and the notches to act as stress risers to start the crack. Not sure if we used a wedge to force the crack or something else.

[FUJIMO]

Jerry, one of the first 50 perhaps?

[FUJIMO]

[FUJIMO]

[FUJIMO]

[FUJIMO]

[FUJIMO]

...studed heads...

[FUJIMO]

[FUJIMO]

[FUJIMO]

[FUJIMO]

[FUJIMO]

[FUJIMO]