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Broken Con Rod 44N677

#1

S

Stanna

Hi all

I have a B & S 44N677 with a broken con rod from a john Deere Z355E twin cylinder. Only 75 hours on the clock and owner says it has been serviced and never been run dry???? Other cylinder runs fine and mower is still moving but obviously next to useless.

Is it worth repairing or is it likely to be too much damage to crank and casing. No external damage and i havent bothered to strip down yet as it seems pointless.

Any thought please.


#2

ILENGINE

ILENGINE

The only way to know for sure is to tear it down and have a look see. You can speculate about what damage there maybe internally, but without opening it up you will not know, and there is potential that the broken parts could cause more damage if continued to be run.


#3

B

Bertrrr

Fixing it is doable but finding out why is more important ,this is a major failure that rarely happens


#4

R

Rocky J

There is no way I could not tear into it . If it is junk, broken piston skirt , cylinder skirt or and camshaft you do not have to put it back together . It might have been the first rod poured on a Monday morning and have nothing to do with oil starvation . Might be a rod cap came off . They do not like to waste time sharpening drill bits so the rod cap bolt hole in the rod is a few thousands of a inch to big and it will end up 50% thread and there is the made in China .


#5

R

Red Good

I could not tell a customer its not worth fixing till it is apart and the cause found . The fact that it has no external damage and it still runs is suspect . Obviously the crank is not broken or the cam shaft either . Not a lot of room in the cases hard to think it broke a rod and did not break more .


#6

L

leeton31

I broke a con rod on my Kubota ZG222, sorry to say lack of oil, however, I pulled it down and replaced con rod, everything else appeared ok, but when about to put back together I noticed the rod punched the crank case and left a dent and crack,
I decided to clean thoroughly and repair the crack with JB weld, crossed my fingers and re-assembled the motor, still running 3 years later.


#7

sgkent

sgkent

you say "the owner" which implies you are the mechanic. Why are you asking here when you haven't even put in time to see what the damage is. Sort of pointless to ask until you know what you are working with. If you don't want to work on it, put one of these on it and send it home.

61Gl92CqTqL._AC_SL1500_.jpg


#8

S

Stanna

Whilst I am a mechanic I have no experience on small engines. The repair is half a favour so I asked in the local mower store and their mechanic said he had zero success with this kind of repair. Lots of parts thrown at it but never ran again properly. Therefore not wanting to waste my time or their money if it's kaput!
Thanks for the advice.


#9

S

slomo

IF you can get the parts, I would fix it. Cheaper than a new 0 turn. Tear it down and post pictures up here. Take pics of everything.


#10

R

Rivets

Even if you could get parts, I would be very careful about fixing it, unless it is not major. As stated you need to tear into it and find and verify the cause. If you need to replace one piston, rod, head, etc. it is best to replace both on a twin. This is major. Second, most techs only warranty repair work for 90 days and as an inexperienced small engine tech, what do you tell your friend if something goes wrong. If you find out it’s major, short blocking or new engine may be the way to go, still would be expensive, but cheaper than a new unit, depending on the direction he wants to go. All of the experienced tech would advise not to spend a lot of time on it, realize that just removing the engine and tearing into it will probably be at least 2 hours labor. That’s why the experienced guys tell customers it’s going to be expensive, either direction you want to go. You may not charge much to do an investigation, but what do you do with your results?


#11

Tiger Small Engine

Tiger Small Engine

Rivets said:
Even if you could get parts, I would be very careful about fixing it, unless it is not major. As stated you need to tear into it and find and verify the cause. If you need to replace one piston, rod, head, etc. it is best to replace both on a twin. This is major. Second, most techs only warranty repair work for 90 days and as an inexperienced small engine tech, what do you tell your friend if something goes wrong. If you find out it’s major, short blocking or new engine may be the way to go, still would be expensive, but cheaper than a new unit, depending on the direction he wants to go. All of the experienced tech would advise not to spend a lot of time on it, realize that just removing the engine and tearing into it will probably be at least 2 hours labor. That’s why the experienced guys tell customers it’s going to be expensive, either direction you want to go. You may not charge much to do an investigation, but what do you do with your results?
Click to expand...
Normally connecting rods break from lack of lubrication. Because engine has never “run dry” doesn’t mean it was not run low on oil amount. Good probability that pistons, rings, cylinders, crankshaft and cam have some scoring due to being run with low oil. Also, low oil causes overheating and further problems result.

You can do a compression test on good cylinder, and look down spark plug hole with endoscope. However, a real engine condition assessment would take removing and cracking the case open.


#12

sgkent

sgkent

Stanna said:
Whilst I am a mechanic I have no experience on small engines. The repair is half a favour so I asked in the local mower store and their mechanic said he had zero success with this kind of repair. Lots of parts thrown at it but never ran again properly. Therefore not wanting to waste my time or their money if it's kaput!
Thanks for the advice.
Click to expand...
My two cents is that when an engine breaks a rod, parts fly around and break other things. To know what is broken you must take it apart. Then if you hand a basket of parts back to the owner they say but I gave it to you assembled. Sometimes you are lucky and maybe only $300 or $400 in parts are needed. If you have other core engines around you of the same kind, sometimes you can frankenstein a motor back together. Generally however, it is cheaper to put a whole new motor on it. And, you better build in a cushion if the guy runs it low on oil again.


#13

Tiger Small Engine

Tiger Small Engine

sgkent said:
My two cents is that when an engine breaks a rod, parts fly around and break other things. To know what is broken you must take it apart. Then if you hand a basket of parts back to the owner they say but I gave it to you assembled. Sometimes you are lucky and maybe only $300 or $400 in parts are needed. If you have other core engines around you of the same kind, sometimes you can frankenstein a motor back together. Generally however, it is cheaper to put a whole new motor on it. And, you better build in a cushion if the guy runs it low on oil again.
Click to expand...
If a person has the time, tools, inclination, and experience, then doing an engine autopsy is really cool and interesting. On the other hand, if you are busy and doing it for a living, it doesn’t pay usually. I am a one person shop and do not offer rebuilds on engines and hydraulic pumps. You cannot sweep the floor, everything in between, and rebuild engines, and keep good service for your customers. Most shops will only remove and replace these days, and they have multiple employees.


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