KT Series I vs M20S

[jstertz]

Guys,
I have a tired KT I in my 682 that I'm refurbishing. I've been watching for a Magnum motor to repower. I have seen a lot of talk on here about folks who have changed in the M18 in place of the KT engines. However an M20 has come up locally for a good price. I would really like to put that in my Cubbie in place of the KT, but I want to know what I'm in for. I already understand that I'm going to have to make some adaptions in the electrical system. What I'm concerned about is the exhaust manifold and especially the PTO. Do I need a different PTO than the one that is on my KT motor? From going through the parts look up it appears that they have a different one for that engine. If I need a different one, how hard are they to come by used?

Also, is there any problem items that I should look for on this motor when I go to look at it and hear it run? The current owner is going to have it set up to start and run. Any info or opinions are much appreciated!

 

[mgonitzke]

The exhaust is the same; The PTO will depend on the crankshaft configuration of the M20. I think the Cub-spec M20 as used in the 2072 has a 1 3/8" diameter shaft, while the M18 and KT-17 have a 1 1/8" shaft.

 

[jchamberlin]

Good Question, Josh --I wouldn't have thought to ask.
Good info, Matt --I'm glad you monitor this site.

 

[jstertz]

Thanks for the response! After I posted, my cousin suggested that I find and engine spec sheet for the motors. I went into the pdf manuals and found the downloadable one for the M18 & M20. I studied it carefully and came to that same conclusion about the PTO. I didn't see anything else that would pose a problem. Again I will ask-has anyone here done this type of conversion? I'm looking for any input regarding the switch.

Matt- how hard is it to change out/set up the PTO to work properly? I went to the parts look up and compared the PTO's for the 1872 and 2072. There were only two pcs different out of the 5pc PTO assembly. Is the diameter of my PTO pulley likely to be the same or different than the pulley for a 2072? If it is different would the 2072 pulley be larger or smaller? I'm just trying to see any possible problems to making this work ahead of time-so I know what I'm getting myself into!!!

Jeremiah- I'll likely be contacting you about the wiring situation as I run into challenges there if you don't mind.

Good, bad, or ugly I think I'm going to go through with this and I'll keep a record of pics on my refurbish thread of the "heart transplant" and maybe others will know ahead of time what they're getting into if they decide to do the same swap!

 

[mgonitzke]

I have an M18 in my 782. Somewhere around here there's a wiring diagram that shows the relay that you need to add to make the wiring work with the Magnum engine.

The 2072 clutch would be the same diameter. Keep in mind that unless you get a Cub-spec engine, you are in uncharted territory because there are hundreds of crank configurations.

 

[jstertz]

Does anyone here have access to the spec number on their M20 powered 2072 (or similar Cub tractor with M20) motor that you wouldn't mind sharing with me? I need the spec number from the engine data plate. I've talked with the reps from Kohler and they said if I had a spec number from a Cub M20 they could cross reference it with the spec number of the engine that I'm looking at purchasing. This would tell me for sure if I'm going to run into problems with the clutch. I would appreciate it greatly.

 

[eburton]

Joshua,
See if this info helps.
https://www.ihcubcadet.com/forum/messages/22774/23434.html

 

[jstertz]

Thanks Eddie for the link. It adds more info to the electrical changes that need to be made but honestly I'm not as concerned about that because you guys have proven to me that it will work. I'm really concerned about whether or not the crankshaft end on this engine will work with a cub pto. If it doesn't and I purchase the engine, I'm not even sure how to rectify the situation. The current owner says that he thinks it came out of a John Deere. However, I did some model by model searching of the JD's produced from the mid 70's to the mid 90's and couldn't find one model that listed the M20 as either the primary or optional engine. Maybe someone owns one that has that motor factory and could fill me in. This is why if someone has a factory equipped M20 cub that could send me their spec number, I could find out from kohler directly what it is out of and if it would work with a cub pto. I want to use my 682 Cubbie when finished for lawn duties, snow blowing, tilling, etc and will need an operational pto. I really do appreciate all your help and insite guys. I don't want to get myself into a situation that costs me more than it is worth!!!

 

[kweaver]

Joshua - You'd better find the specs b4 you buy it because I know that in the K301 engines Ford called for a bigger crank stub diameter than IH.

You never know what you'll find when buying engines from other manufactures.

Keep searching , you'll find it

 

[kweaver]

Checking on my PC I would say that either Charlie or Kraig has the info ... because it's in the <u>Kohler Crankshaft Reference Manual</u> on page 61.
I don't have the complete manual !!

 

[kmcconaughey]

I don't have the complete Kohler Crankshaft Reference Manual either...

 

[jstertz]

Thanks Guys for the help. I got the serial number for the engine I would like to buy (which incidently was 49512), called the technical rep from Kohler and he looked it up. He gave me the dimensions of the crank and said that the engine was set up for a cub cadet! Sounds like the crisis is averted! Evidently the current owner got his yellow and white mixed up with his yellow and green!


If everything looks as it should I'll purchase it and then post some pics tonight. Thanks again for the help. I'll certainly be picking your brains and your expertise for all the help I can get as I retrofit this dude.

I've noticed from culling through the titles of threads in this section some of the problems that people have had with these motors. The coil pack seems to be something to look for, the carb, magnet issues. The owner has is set up to run independently. Is there anything I should be alerted to look for?

 

[jchamberlin]

Josh, congratulations on really doing your homework, again, I would only have thought to ask the questions AFTER I made the purchase.

I would definitely try Cylinder Balance Test. The procedure is given in my Briggs & Stratton manual and it can be very revealing about the condition of each cylinder vs. the other, which in turn, can tell you a lot about the general condition of the engine itself.

What you do start the engine and run it at its full no-load RPM, then short out one spark plug and look/listen for significant changes in how the motor runs (or if it stops); then short out the other spark plug and look/listen again.

If the RPM drops significantly or stops when one of the cylinders is shorted out, there is a problem with the OPPOSITE cylinder. (In other words, shorting out the weaker cylinder has less effect on engine performance than shorting out the stronger cylinder.)

When I tried the Cylinder Balance Test on my 16 HP Briggs, the motor REALLY smoked when one of the cylinders was shorted out, but not when the other one was shorted. ==>The motor failed less than 10 hours later.

According to the Briggs manual, conditions that can affect one cylinder include:

1. Bad Spark Plug
2. Bad Spark Plug Wire
3. Leaking Head Gasket
4. Leaking Intake Manifold Gasket
5. Valves
6. Rings
7. Piston
8. Cylinder

I think its a great diagnostic test which is not available to single-cylinder owners. It is supposed to be run with a tachometer, and changes greater than 75 RPM indicate a problem; if the change is less than 75 RPM, the engine is deemed OK.

I think if the M20 passes the Cylinder Balance Test, it is a good indication that the motor is in good shape mechanically; if it fails the test, I would investigate further by visual examination of the spark plug wires, carbon spots around the head, general condition of the oil, etc. as well as the vibes you pick up from the seller, his property, and the shape of his other equipment. But that's just me.

Good Luck, I hope everything works out for you.

Matt is right, there is a wiring diagram for an M18 conversion into a 782 on the site somewhere. But if you have problems, I'll be glad to help.

 

[jstertz]

Well I took the plunge! Based on the info received from running the spec number and being assured that this was set up for a Cub, I was on the right track. The owner was unsure of the hours. He had purchased it four years ago with the intent to install it in his Simplicity tractor if the engine ever failed. It didn't however and he finally sold that tractor. Now he was ready to sell the engine. It seemed to start and run fine but I'm going to check it over good before I completely install it on the Cubbie. He said he wasn't sure how many hours it had but the oil filter had painted "1121hrs" on it so I'm going to say that it has somewhere in that 1200 hour range! According to the serial number it was manufactured in 1987. Unless there is another Cub model that I'm not thinking of in 1987 with an M20, my guess is that it was installed originally on a 2072. I'm going to place an add in the wanted section for a 2072 PTO because I'm going to need one of those if I want to run my implements. I'll post the pic I took of it tonight when I got it home and on the bench but it is pretty dark. More good pics to follow.

i can't wait to see how that beast is going to work on the Cubbie. My guess is that it will be a real improvement.

Jeremiah--Thanks for the test, I wish I had gotten it before I made the purchase but that is the way it goes. I will check it now though to look for potential problems! It is much easier to clean the starter, change the coil, etc now before the engine is installed. Thanks!

 

[jchamberlin]

Looks good, Josh. I think you'll be OK.

 

[kmcconaughey]

This just in from Jim D.,

 

[jstertz]

Thanks Jim D/ Kraig for the crank charts. How do you decipher the numbers for what type of equipment it was originally installed on?

 

[bjames]

A 2072 used the 52-014-71-S crank. PTO end is 2-11/16 X 1-1/4.

 

[jstertz]

Thanks Bill--That is the crank that my M20 has in it. Now all I need is the correct PTO and some time to do the transplant! The KT will become a wall hanger for my IH memorabilia and hopefully the Magnum will serve me well in my 682 Cubbie. I will be posting comparison pics and detailed install pics on my refurbish thread.

 

[bjames]

You need the 717-3043 or 917-3043 clutch, around 500.00 new.