CV15S cylinder damage

[VegetiveSteam]

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

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.

 

[Affordable in Indy]

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.

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.

 

[Moparjoe499]

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?

I have done this before to an engine without any problems. I just ran a cylinder hone to clean it up.

 

[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.

 

[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/

 

[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.

 

[Moparjoe499]

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.

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.

 

[doug9694]

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.

 

[doug9694]

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

 

[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