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CV15S cylinder damage

#1

A

Affordable in Indy

I have a customer who has a 20 year old John Deere SST15 with a Kohler CV15S engine. He ran it without oil and, well, you know what happened. I'm trying to put a new crankshaft and connecting rod in it. However, when the connecting rod failed, it impacted the bottom of the cylinder and broke a chunk out. There appears to be wear marks in the cylinder. I don't think the piston travels down to where the damage is. Can I get this engine running or is the crankcase unusable?

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#2

Fish

Fish

I wouldn't bother with it myself. If it doesn't last very long, it will be a lot of money wasted, and your name will be associated with it.


#3

B

bertsmobile1

that will be fine
get a die grinder or similar and make the hole smooth left right & top bottom so the edges do not break away


#4

A

Affordable in Indy

Thank you for the replies.
Bertsmobile1, have you repaired an engine with this kind of damage before?


#5

V

VegetiveSteam

I agree with Bert that it will be fine. I would let the customer know what you found and let them make the choice on how to proceed.


#6

A

Affordable in Indy

VegetiveSteam said:
I agree with Bert that it will be fine. I would let the customer know what you found and let them make the choice on how to proceed.
Click to expand...
Ok. That's a good idea. Thank you.


#7

A

Affordable in Indy

Fish said:
I wouldn't bother with it myself. If it doesn't last very long, it will be a lot of money wasted, and your name will be associated with it.
Click to expand...
Thank you for your reply, Fish. You have a good point.


#8

A

Affordable in Indy

Ok, I have one more question. Do you think I should replace the piston rings since I have to remove the piston anyway?


#9

StarTech

StarTech

With that lick I would be careful inspecting the crankcase for damage too. Usually here I find it at least cracked.


#10

A

Affordable in Indy

Ok, I have one more question. Do you think I should replace the piston rings since I have to remove the piston anyway?
StarTech said:
With that lick I would be careful inspecting the crankcase for damage too. Usually here I find it at least cracked.
Click to expand...
Ok. I'll give it another look.


#11

V

VegetiveSteam

Affordable in Indy said:
Ok, I have one more question. Do you think I should replace the piston rings since I have to remove the piston anyway?
Click to expand...
I guess I'll sort of start over with my reply as I just gave my opinion on the question about the chunk out of the cylinder. If i found no other damage to the block and the bore was in good shape and ring travel did not enter into the broken area, I would have no problem trying get the engine up and running if it were my own and not a customer's. I'd probably lightly hone the cylinder and install new rings. Since it does belong to a customer, I might have to decline trying to repair it.

If you do go forward with it, I would start by measuring the cylinder and see if it would need to be bored. If it does, you would then need to find out if an oversized piston is even still available for that engine and now, you're getting into the probably not worth it area.


#12

A

Affordable in Indy

VegetiveSteam said:
I guess I'll sort of start over with my reply as I just gave my opinion on the question about the chunk out of the cylinder. If i found no other damage to the block and the bore was in good shape and ring travel did not enter into the broken area, I would have no problem trying get the engine up and running if it were my own and not a customer's. I'd probably lightly hone the cylinder and install new rings. Since it does belong to a customer, I might have to decline trying to repair it.

If you do go forward with it, I would start by measuring the cylinder and see if it would need to be bored. If it does, you would then need to find out if an oversized piston is even still available for that engine and now, you're getting into the probably not worth it area.
Click to expand...

Thank you. That's all good information. I've never messed with boring out a lawnmower engine. I won't be doing this repair if that's required. I'll check for more damage.


#13

Moparjoe499

Moparjoe499

Affordable in Indy said:
I have a customer who has a 20 year old John Deere SST15 with a Kohler CV15S engine. He ran it without oil and, well, you know what happened. I'm trying to put a new crankshaft and connecting rod in it. However, when the connecting rod failed, it impacted the bottom of the cylinder and broke a chunk out. There appears to be wear marks in the cylinder. I don't think the piston travels down to where the damage is. Can I get this engine running or is the crankcase unusable?
Click to expand...
I have done this before to an engine without any problems. I just ran a cylinder hone to clean it up.


#14

Fish

Fish

I would suggest cleaning and inspecting the cylinder walls closely, as it doesn't look too perky from here. The cost of a new crank and rod is quite high, to be throwing into a cylinder with damage.
You usually can buff out the cranks, btw. It usually is just pasted on aluminum.


#15

L

lowmow

I would replace the rings.I think it would be silly no to since the piston is already out.Look for scarring on the piston skirt in the area of the missing chunk,and check the rod for bending and check the big end for out-of round and proper clearances.I use Plasti-Gauge:link below:
https://www.yotashop.com/plasti-gau...ng-clearance-tool-plasti-gauge-001-003-mpg-1/


#16

ChiefH

ChiefH

It seems an engine that old, and with the damage you described, I would let the owner decide on a new engine or continue to repair the damage engine.


#17

Moparjoe499

Moparjoe499

Fish said:
I would suggest cleaning and inspecting the cylinder walls closely, as it doesn't look too perky from here. The cost of a new crank and rod is quite high, to be throwing into a cylinder with damage.
You usually can buff out the cranks, btw. It usually is just pasted on aluminum.
Click to expand...
The rod just hit the bottom. The rest of the cylinder will clean up with a cylinder hone. After you hone the cylinder, I would go with .010 over rings and file fit them.


#18

doug9694

doug9694

Fish said:
I wouldn't bother with it myself. If it doesn't last very long, it will be a lot of money wasted, and your name will be associated with it.
Click to expand...


#19

doug9694

doug9694

Be sure that the crank, cam and other bearings are still good. If not then look on Ebay or etc.


#20

B

bertsmobile1

cranks get dumped in warm 1/2 strength pool acid or boiled in caustic soda, both will strip off the built up alloy
Check for roundness , rare to find one oval
check the bottom of the cam shaft boss carefully for cracks at both ends, common for them to crack, usually at the sump end
Give all crank journals a very light polish , do not worry about groves, they become oil channels but ridges need removing
Beg borrow or go to a repair shop& have a bottle brush hone 100 to 160 grit run through the bore, most shops will do that while you wait for $ 20
Some car parts stores will hire out a hone & micrometer + tension wrench is you need them
Fit new std rings .
FWIW I ride vintage & veteran motorcycles.
Most have a pressed in cylinder liner and it is common for them to slip & rotate in the bore so the con rod punched out the sides .
Right now i have 1916 500cc wherer all of the spiggot has been chopped away by the con rod.
It runs fine


#21

Moparjoe499

Moparjoe499

I have done this before. I have no control what other people do or the decisions they make. Some people are scared of their own shadow. Once people found out I worked on mowers, they were coming from other counties looking for me and I didn't advertise anywhere. I have a parts supplier.


#22

Moparjoe499

Moparjoe499

bertsmobile1 said:
cranks get dumped in warm 1/2 strength pool acid or boiled in caustic soda, both will strip off the built up alloy
Check for roundness , rare to find one oval
check the bottom of the cam shaft boss carefully for cracks at both ends, common for them to crack, usually at the sump end
Give all crank journals a very light polish , do not worry about groves, they become oil channels but ridges need removing
Beg borrow or go to a repair shop& have a bottle brush hone 100 to 160 grit run through the bore, most shops will do that while you wait for $ 20
Some car parts stores will hire out a hone & micrometer + tension wrench is you need them
Fit new std rings .
FWIW I ride vintage & veteran motorcycles.
Most have a pressed in cylinder liner and it is common for them to slip & rotate in the bore so the con rod punched out the sides .
Right now i have 1916 500cc wherer all of the spiggot has been chopped away by the con rod.
It runs fine
Click to expand...
It's not that hard to figure out except for those who have not done this kind of work with engines.


#23

StarTech

StarTech

I think what Bert refers to as pool acid is Muriatic Acid if so then using it can be dangerous until done outdoors with good ventilation. It produces toxic fumes when exposed to moisture in the air. But will remove aluminum transfer from the crankshaft journals. Once the aluminum is remove the acid must be neutralized with water and the part immediately oiled or greased because if you don't the crankshaft will flash rust and continue rusting. Also keep all metals out of the area as they can flash rust just from the fumes off the Muriatic Acid.

As I noted the toxic fumes can take your breathe away so be extremely careful using Muriatic Acid.


#24

Fish

Fish

You need to closely inspect the areas where the camshaft rides, as you may very well see cracks there, and your expensive repair would crumble in short order.
As far as being scared, well. Working on this stuff for a living, I have found folks that had bad results go out of their way to let everyone know it, forever.

I want my repairs to be good, and lasting, and well worth the money invested.
I save repairs like this for my own stuff usually, in an experimental way..


#25

StarTech

StarTech

Fish that is part of the learning process. You do experimental repairs on your own equipment as most customer expect a lot more then can't accept it when something this fails. I don't attempt repairs on customers machines on the experimental side; unless, I have already proven to myself that it works or recommend by the manufacture.

Basically it is training ourselves how to do the repairs correctly. Personally I would like a pro looking over my shoulder and providing guidance than going on my own but most shops around here are afraid they going to lose business if they help out a learning tech. It is a shame in a way as many skills never get passed along.

It is like the diesel mechanic along the state line came up here Saturday with a fairly new compressor. He a customer of his brought in after only ran 30 minutes. He was lost when it came gasoline engines. I let him watch me troubleshoot and repair the problem. His customer had put in bad fuel which clogged the carburetor. The diesel said will bring work for me as he simply don't the time or the equipment do that kind of work. And personally I don't the strength to work the big stuff anymore.


#26

Fish

Fish

StarTech said:
Fish that is part of the learning process. You do experimental repairs on your own equipment as most customer expect a lot more then can't accept it when something this fails. I don't attempt repairs on customers machines on the experimental side; unless, I have already proven to myself that it works or recommend by the manufacture.

Basically it is training ourselves how to do the repairs correctly. Personally I would like a pro looking over my shoulder and providing guidance than going on my own but most shops around here are afraid they going to lose business if they help out a learning tech. It is a shame in a way as many skills never get passed along.

It is like the diesel mechanic along the state line came up here Saturday with a fairly new compressor. He a customer of his brought in after only ran 30 minutes. He was lost when it came gasoline engines. I let him watch me troubleshoot and repair the problem. His customer had put in bad fuel which clogged the carburetor. The diesel said will bring work for me as he simply don't the time or the equipment do that kind of work. And personally I don't the strength to work the big stuff anymore.
Click to expand...
My 5 years of working on tractor/trailers helped me quickly have a distaste for winter.


#27

StarTech

StarTech

Smacking your hands in the winter does hurt alot more...:whistle:

Going for the :coffee::coffee::coffee: of Java now and then going to town and fight the crowds for air compressor parts.


#28

Moparjoe499

Moparjoe499

Fish said:
You need to closely inspect the areas where the camshaft rides, as you may very well see cracks there, and your expensive repair would crumble in short order.
As far as being scared, well. Working on this stuff for a living, I have found folks that had bad results go out of their way to let everyone know it, forever.

I want my repairs to be good, and lasting, and well worth the money invested.
I save repairs like this for my own stuff usually, in an experimental way..
Click to expand...
There is a reason people would bring their lawn equipment to me. The guy in town would charge them just to look at it and it would cost them dearly for a simple fix and they didn't even get a kiss.


#29

H

hlw49

bertsmobile1 said:
cranks get dumped in warm 1/2 strength pool acid or boiled in caustic soda, both will strip off the built up alloy
Check for roundness , rare to find one oval
check the bottom of the cam shaft boss carefully for cracks at both ends, common for them to crack, usually at the sump end
Give all crank journals a very light polish , do not worry about groves, they become oil channels but ridges need removing
Beg borrow or go to a repair shop& have a bottle brush hone 100 to 160 grit run through the bore, most shops will do that while you wait for $ 20
Some car parts stores will hire out a hone & micrometer + tension wrench is you need them
Fit new std rings .
FWIW I ride vintage & veteran motorcycles.
Most have a pressed in cylinder liner and it is common for them to slip & rotate in the bore so the con rod punched out the sides .
Right now i have 1916 500cc wherer all of the spiggot has been chopped away by the con rod.
It runs fine
Click to expand...
Mix up a solution of red devil lye and water, it will do the same thing if you can still get it since they say it is used to make drugs


#30

B

bertsmobile1

hlw49 said:
Mix up a solution of red devil lye and water, it will do the same thing if you can still get it since they say it is used to make drugs
Click to expand...
same animal NaOH / Sodium Hydoxide / Caustic Soda / Lye / Washing soda , used to the active ingredient in most drain cleaners to break up the fat balls & hair.
also a favourite way of making bodies vanish


#31

Tiger Small Engine

Tiger Small Engine

bertsmobile1 said:
same animal NaOH / Sodium Hydoxide / Caustic Soda / Lye / Washing soda , used to the active ingredient in most drain cleaners to break up the fat balls & hair.
also a favourite way of making bodies vanish.
Click to expand...



If the piston, rings, and cylinder are scored, and if so, to what extent, I would definitely hesitate to go forward with this repair. The fact that this engine was run low on oil, is not good, at all. Seems like parts and labor will add up quickly on this engine. The Kohler CV15S engine is a good solid engine, but is it worth hundreds and hundreds to partially rebuild? Probably not.


#32

Moparjoe499

Moparjoe499

Tiger Small Engine said:
If the piston, rings, and cylinder are scored, and if so, to what extent, I would definitely hesitate to go forward with this repair. The fact that this engine was run low on oil, is not good, at all. Seems like parts and labor will add up quickly on this engine. The Kohler CV15S engine is a good solid engine, but is it worth hundreds and hundreds to partially rebuild? Probably
Click to expand...

Tiger Small Engine said:
If the piston, rings, and cylinder are scored, and if so, to what extent, I would definitely hesitate to go forward with this repair. The fact that this engine was run low on oil, is not good, at all. Seems like parts and labor will add up quickly on this engine. The Kohler CV15S engine is a good solid engine, but is it worth hundreds and hundreds to partially rebuild? Probably not.
Click to expand...
A cylinder hone will clean up any scuffs. Stop being a wuss.


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