first rebuild... lost on rods and VRO

[boltbreaker]

I'm doing my first complete rebuild on a 1987 Johnson VRO 40 HP outboard. I already have the block work done(bored .020 over) and have all the parts for assembly. I had to remove the rods from the crankshaft to remove the crankshaft assembly from the powerhead. When I did, I didn't take note which way the rods were pointing. I know which one is top, and which one is bottom, but have no clue which way to put the rods. I know to keep the rod caps with the same rod, but does it matter if I turn a rod around backwards? Both of the rods have a mark scribed into the piston end to desginate something. I think either I should put the scribe on both sides or oposite sides, not sure which though.<br />I also plan on not using the VRO. I don't know what a VRO is(besides oil injection). I thought just mixing the fuel in the gas tank would be suffecient, until I heard of a "VRO disconnect kit" available from Johnson dealers. Is it necassary to install the "kit" or would I be safe just plugging off the lines? Thanks so much in advance to all those who follow up. Jeff

 

[G DANE]

Re: first rebuild... lost on rods and VRO

Hi boltbreaker, welcome here.<br /><br />The lower rodends are marked, as turning the cap will make the bore out of round. These rods were machined, and then broken apart. I dont know if these can be turned, I never had a 40 apart, but on the V4´s there is a lubricating hole that must turn upvards. Be carefull aligning rodends look at this previous post: posted August 26, 2004 12:18 PM <br />--------------------------------------------------------------------------------<br />These rods were machined, and then broken into two. Every rod cap has to go on the rod where it belongs. There is a mark on one side to let you make sure you didnt turn the cap. If they were fittet wrong you can make a line rollers have to cross at high speed and it will damage them. I usually align caps as good as I can by the grinded 4 edges. Then check and check along when I apply torque. At last try with the lead tip of a pencil if there is external edge showing misalighment. If you accidently got caps mixed, you will usually be able to tell which belongs where by trial and error and feeling.<br /><br />You can remove oil line from tank, plug inlet and still use fuelpump side of vro. Just trace warning wires and unhook them. Be sure the overheat warning wire is still on.

 

[R.Johnson]

Re: first rebuild... lost on rods and VRO

On the big end of the rod is a small raised boss, or "Dot" on both the rod, and end cap! these must align. There is an oil hole on the wrist pin end! this must face up. As pointed out, these rods are first machined, then the caps broken off. If you look at the rod, and cap in a good light, you will see a slight jagged edge. Turn the cap around, and you will see that the jagged edge won't match. Keep in mind, if you get the cap on wrong, or worse yet! get the caps changed around between rods, when you torque it down, you will ruin the rod. If you have the cap on the wrong rod, you will ruin both rods. The cap on one, the rod on the other. If you know you have them right, go slow when tightening them down. Go from side to side, checking with a pencil, or a finger nail as you go.

 

[Mark42]

Re: first rebuild... lost on rods and VRO

Hi Folks!<br /><br />You describe the rods as being "machined and broken in two". Are the rods really "broken" or sheared after machining? Wouldn't that cause distortion? <br /><br />How is that done? <br /><br />Just curious. Mark.

 

[Dhadley]

Re: first rebuild... lost on rods and VRO

These type rods are actually known as "cracked rods". The rods are cast as one piece and then holes are drilled sideways in the big end. Usually 2 on each side. The rod is then held in place and the end is sheared off. It all happens very quickly so it will not distort them. The theory is that nothing fits together as good as cracked parts. The downside is that they cannot be rebuilt like automotive rods.

 

[Mark42]

Re: first rebuild... lost on rods and VRO

Dhadley,<br /><br />Thanks for explaining!<br /><br />Mark