Command 25CV Cylinder Wall Damage

[hlw49]

CV25 with nickasil cylinder liners? Never saw a CV25 with that all I have ever seen have cast iron liners.

 

[Riddler]

CV25 with nickasil cylinder liners? Never saw a CV25 with that all I have ever seen have cast iron liners.

I was surprised to, but that's why posted the photos. The delamination is interesting, to
say the least.

FWIW, I found this from a Kohler publication:

"Some CH25-26 engines feature POWER- BORE™ cylinders a special patented nickel- silicone plating process for increased power, superior oil control, reduced exhaust
emission, and virtually permanent cylinder life. POWER-BORE™ cylinders cannot be resized or honed as described in the following procedure. If a plated cylinder bore is damaged or out of specification, use a new
miniblock or short block to repair the engine."

 

[ILENGINE]

I'm willing to go with a complete engine if it won't present problems hooking up to the existing cables or wiring harness. When I research availabilty, complete CV-730 engines (which I understand replaced the CV-725 I have) seem tied to make and model of mower. The complete engine for my mower shows as "discontinued." What would be the trick to ordering a complete engine that I would have the least (if any) modifications to install?

The CV732-3014 or CV742-3022 which are both spec'd for Scag. so may need to do a little more research. Looks like crank dimensions are correct. 6 pin wiring harness should be the same connections.

 

[hlw49]

I was surprised to, but that's why posted the photos. The delamination is interesting, to
say the least.

FWIW, I found this from a Kohler publication:

"Some CH25-26 engines feature POWER- BORE™ cylinders a special patented nickel- silicone plating process for increased power, superior oil control, reduced exhaust
emission, and virtually permanent cylinder life. POWER-BORE™ cylinders cannot be resized or honed as described in the following procedure. If a plated cylinder bore is damaged or out of specification, use a new
miniblock or short block to repair the engine."

It says some CH25-26 engines. Those are horizontal shaft engines. Did it also say CVs as well?

 

[hlw49]

Don't know if they do Kohler engines or not you may want to check this out. https://millennium-technologies.com/cylinderrepair/

 

[Riddler]

The main concern when replacing engine is crankshaft diameter and length. If staying within the same series of engine say going kohler command to kohler command then things are fairly simply. Changing brands or series can get interesting but in most cases can be doable. I was trying to see what was available in that size engine and looks like almost al the engines in the range are set up with the cyclonic HD air cleaner not like your more pancake style filter but if room permits isn't really a big deal either.

Looks like you have found a short block used on your current engine. My distributor doesn't show any in stock so may be hard to track one

It says some CH25-26 engines. Those are horizontal shaft engines. Did it also say CVs as well?

TBH, I can't recall if it mentioned CVs as well. I think I found the statement in a CH repair manual.

Wiki says this in their write up on nikasil:

"The coating was further developed as a replacement for hard-chrome plated cylinder bores for Mercury Marine Racing, and Kohler Engines . . ."

I also came across some mention in an online Q&A with a small engine performance shop that Kohler and others dabbled in plating beginning in 2002. The mower that this CV powers is an early 2000s MTD Pro.

I figure that if Kohler was doing it on the CH, they probably did it on the CV. Regardless, as you can see from the photos that are part of my initial post, the cylinders in this engine are definitely coated, not iron sleeved. The coating in both cylinders has delaminated. I bought the machine new 20 years ago. Full disclosure, I have misused and neglected it since day one (long story). I'm surprised it held up this long, lol. I'm in a better spot these days to care for the equipment, so if and when I get this mower running again, I'll treat it better.

 

[StarTech]

Yes the same comment is in the CV25 service manual.

 

[VegetiveSteam]

Kohler only used Nikasil on the early CV and CH 25 engines. The issue you have was typically caused by dirt ingestion. The Nikasil was supposed to stand up better to dirt ingestion but unfortunately it didn't. Kohler changed to cast iron liners on the 25 hp just like the rest of the Command series sometime in the late 90s if my memory serves me correctly.

 

[VegetiveSteam]

The complete engine for my mower shows as "discontinued."

Do you have the original spec number of the engine? Should be 69XXX. MTD normally used a pretty basic spec engine so finding a replacement shouldn't be too hard. I have an engine comparison spreadsheet I can check if you can post the original engine spec number. The spreadsheet lets me compare everything from type of air filter and crankshaft to the type of charging system and wire harness.

Okay found your spec # in another post you made. This is what I found from my comparison spreadsheet. The big thing is would you have room for the Heavy Duty canister style air filter. It shows your original engine had a WAWB air filter system which stands for Wide Area Walk Behind.

I found a CV742-3016 that looks like a good replacement if you have room for the air filter. Same crankshaft and same wiring harness so should pretty much drop right in. The CV742-3016 is current production and shows in stock at distributors in St. Louis, Memphis and Kansas City.

 

[Riddler]

Do you have the original spec number of the engine? Should be 69XXX. MTD normally used a pretty basic spec engine so finding a replacement shouldn't be too hard. I have an engine comparison spreadsheet I can check if you can post the original engine spec number. The spreadsheet lets me compare everything from type of air filter and crankshaft to the type of charging system and wire harness.

I do. Here is a pic of the engine tag: