connecting rod torque value

[shearpin]

I'm looking for the connecting rod torque value for a 1996 mariner 6o hp 3 cylinder. I have conflicting values one source states 190 in/lbs with a 1/4 turn. and another one states 270 in/lbs.

 

[emckelvy]

Re: connecting rod torque value

If those are stretch bolts (torque-to-yield), be sure to use new ones. Torque-to-yield bolts will break if re-used as they have already been stretched to the point of permanent deformation the first time they were tightened.

The 270 in-lb value sounds like it would be for non-stretch bolts. I know that for the older Inlines, the 'cracked cap' style of conn rod, which did not have a thru-bolt but had holes threaded into the rod itself, used torque-to-yield rod bolts.

What kind of manual are you using? I'd trust anything put out by Merc or Seloc but be wary of others (like Chiltons) as their info is not always the best.

Whatever you do, make absolutely sure to resolve this before you reassemble. It'd be a terrible thing to have the motor blow up after all that work, because of a bad part or wrong spec.

Maybe one of the old-timers here who knows this spec off the top of their head will chime in.

HTH...........ed

 

[gonogo]

Re: connecting rod torque value

I should stay out of this, but I never learn. All bolt stretch when torqued, its called clamping load. If it is torqued to deform, it will fail in service, That is why you torque bolts, so they don't deform.
Torque to yield takes out the drag factor, which can be variable. The 1/4 turn will remove the drag factor, the 270 in/lb will be same as 190 + 1/4 with drag being normal.