Mixed up rod bearings D'oh !

ice cold

Recruit
Joined
Jul 31, 2002
Messages
4
I bought a 87 yamaha 115 in a cardboard box. I have had the block bored .20 over new pistons ect. The rod bearings were in a can, mixed up. They are needle type in split cages and are ingood shape as the motor has very low hours. Is it critical that each half go togeather back in the same rod that they came from or can I just put them back in mixed up? New ones are very costly. I have gotten conflicting answers on this subject. Has anyone delt with this subject?
 

grandx

Petty Officer 1st Class
Joined
May 21, 2001
Messages
383
Re: Mixed up rod bearings D'oh !

The upper and lower rod should remain together as they are machined as a pair usually. I'm not certain about the bearings themselves, but I cannot imagine why they could not be mix matched. wait for other replies to confirm.
 

rickdb1boat

Supreme Mariner
Joined
Jan 23, 2002
Messages
11,195
Re: Mixed up rod bearings D'oh !

I'm sure others will reply to this, but I have always heard that they Must go to the same place they came out of. Something about the wearing characteristics that form after a while. Although, needle bearings I'm Not sure of, so wait for other responces!
 

BKool68

Petty Officer 1st Class
Joined
Oct 14, 2001
Messages
259
Re: Mixed up rod bearings D'oh !

It will not make a difference where you put them. Just be certain they are clean and free of pitting. Use clean 2-cycle oil for assembly lube. That goes for the cylinder walls and pistons also. Make certain everything spins freely before you button everything up.
 

MGuckin

Senior Chief Petty Officer
Joined
Jun 10, 2001
Messages
760
Re: Mixed up rod bearings D'oh !

Agree with bk.<br />Unless the crank has been (chrome) plated and reground, it is softer than the bearings. <br />Lube it, slap it together and lube again.
 

HowieDean

Seaman
Joined
Jun 28, 2002
Messages
66
Re: Mixed up rod bearings D'oh !

Mix and match all you want it's not a problem..<br />CLEAN - CLEAN - CLEAN as mention above the only thing that critical is the rod caps... they have to stay as a unit... as they are cast in one piece, frozen, then broken appart... no two break the same.. so they have to be kept together...<br /><br />I like to count out the bearings for each rod and stack them in groups... it's easy to forget and miss putting one in... Unless you are sure that the rod bolts have never been over torqued buy new ones... I re-use rod bolts some times but I will never use any that come from a motor that some one else might have put a wrench on the rod bolts... They WILL fail if over torqued....<br /><br />I like to do my assambly as follows...<br /><br />Put the first piston in<br />Install all the bearing and snug the rod bolts with a quater inch drive rachet. "snug" <br />Spin the shaft and watch the cage, it should rotate as you turn the crank...<br />Feel for any tight spots...<br />Loosen the rod bolts 1 turn...<br />Then do the next one... etc.. etc..<br />After you are sure they all turn freely go back to the first one.. pull the rod bolts... Put your locktight on em and torque to spec.. rotate the crank and make sure the cage still turns and there are no tight spots.. continue till you get to the last one...<br />DO NOT over torque the bolts..
 

Hooty

Rear Admiral
Joined
Oct 2, 2001
Messages
4,496
Re: Mixed up rod bearings D'oh !

How do you keep the rings in the right position (with reguard to the pin in the ring groove) when compressing rings with ring compressor?<br /><br />TIA & c/6<br /><br />Hooty
 

HowieDean

Seaman
Joined
Jun 28, 2002
Messages
66
Re: Mixed up rod bearings D'oh !

I like to use a hose clamp instead of those **** black steal wring compressors..."they cut my fingers and are just a general pain in the *** " get both rings resting against the pins on the same side.. tighten the clamp.. Get it snug.. look straight down the pison and look for a gap.. if you have a gap gently rock the clamp and the wring will snap in... then tighten the clamp pretty snug.. I use a hammer handle to drive the piston into the cylinder... hold the clamp flat against the top of the block and give it a clean sharp wrap with the handle... it will prop right in....
 

Hooty

Rear Admiral
Joined
Oct 2, 2001
Messages
4,496
Re: Mixed up rod bearings D'oh !

Thanks Howie,<br />I just posted the same question but a different place.<br /><br />I've got a picture somewhere of you coming out of the hole and the boat is pointed straight up.<br />It's a great shot.<br /><br />c/6<br /><br />Hooty
 
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