Replace main bearings or not?

[Brinkmanship]

I have my 1985 mariner 115hp tore down and will be replacing the piston assemblies with new Weisco's. Do you think I should or have to replace the main and connecting rod bearings? I really don't want to spend the money or time but don't want a failure in 2 months either. What has your experience been?

[qmaster023]

you did all the labor to tear the motor down. the engine is an older engine. if you have to replace parts because they are worn out then i would replace everything. you said it best you rebuild and 2 months later if something happens what are you left with. no one likes to spend more money however a hole in the block will cost more. it is only my opinion but i would replace wrist pin and main bearings.

[Jay Smith]

I ALWAYS replace bearings, cheaper than cranks and blocks..

"If you have the money and time to do it over and replace ALL the torn up parts and damages, you had the money and time to do it CORRECTLEY the FIRST time "

IMO : These stressed to the max High Performance engines fail even with the best , new parts money can buy installed in them due to stress and fatuige, I'll be damned if I'M gonna short cut one to save a hundred $$ and run used bearings and cost my customer thousands, to blow up a 5500 rpm 150 steel sleeve fishing motor is on one plane of money to repair or replace to smoke a 11,000 + rpmed 280 , 260 or a Drag by short cutting ANYTHING comes into another realm of MEGA dollars and IMO foolishness...Like I've said a zillion times if ya short cut yours or a customers motor and it lives your a hero if it fails your a zero wiping HUGH amounts of egg off your face...

Good luck,

[Dave S]

I replace what I see as worn or broken. On the old 115 motors the mains sometimes take a real beating. The outer bearing shells get worn on the outside and the part that holds them in the block gets worn too. I have seen them crack the outer race in real bad cases. The reed blocks also get worn where the crank spins and it will lead to hard starting. Also the top of the bores get worn with extream abuse. The end caps also get sloppy. It really depends on how bad the motor was misused or not used up. V6 motors are a different story. Usally the oil injection gear goes bad and costs ya ## money.:eek: Or the ring pins fall out.:eek: If ya need any parts for your rebiuld let me know. I have some used parts Merc might not have in stock for the old motor.

[T-REX]

If they ain't blue and look good, and tha crank looks good, why replace them??...I reuse bearings all tha time, if they look good...don't take a rocket scientist to know if a roller bearing is good or not...If theyz any doubt in ya mind, change it!!...If it looks az good az a new one, why change it??...

I am far from bein politiklly correct, and don't do what tha guru's do, but I have motas still runn'in fer yeerz, and sum that have been pasted tha 11k mark and all have been blessed wit used bearings!!!.....I give tha owner tha option...U wanna spend money, we go new, U want to save money, we use good used stuff....Az I said, if it looks questionable to U, change it....If it lookz good az a new one, why not use it...It's already been stress tested!!!

[NEECAPR]

Bearing Replacement!!??
I go along with Rex' advice. And, I'll take it a step farther. If you put a bearing set back together in EXACTLY the position it was installed before, it's much better than a new one in the same worn parts. It is already an exact contact fit which is what a break-in does anyway. It's well beyond the infant mortality period and on its way to infinite life---or until its lubrication or alignment luck run out--as in lean running carbs or injectors, bad circ valves, or broken piston. Same lousy outcome here with a new bearing.
BUT!! If you want to have this advantage, you need discipline. The rods all have to go back in the same position and all bearing cages need to go on the same journal and with the same side up. All of this takes you back to the disassembly where you need to mark or position everything carefully. Of course, the CM outer races have well defined up/down orientation.
If all new bearings and their expense make you feel better--go for it!! It helps keep a lot of people in business, including many of my aquaintances in bearing manufacture.
Regards, Cy

[rwunstel]

Believe in the old sayin.....PAY NOW OR PAY MORE LATER!!

[Jay Smith]

Guess you and I will have to respectively agree to disagree Cy....

But thats what makes the world go around and this site sooo successfull as it is for opinions and sharing of information, huh ?

Jay Smith

[rwunstel]

Yep Mr. J, if everyone thought alike, this would be a hell of world. "and a lot of E'rude people would be out of work and on welfare"

[bigbore]

WHATS the price-tag on all new crank,rod,n pin beerings?nothing nice,i'm thinking the crank beerings are 100.00 a piece n there's 4.then rod n pin.