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Discussion Starter · #1 ·
I significantly raised the RPMs on the 27HP Command in our DGT6000, and would like to add one of the factory oil coolers that these engines had on higher end models. Has any one bought a Kohler oil cooler kit and installed it?
 

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There is a good thread here from the Cub forum showing a full install.

There are also notes from me on the install I did just using a used oil cooler and adapter plate. It all depends on how original you want it to be and how much money you want to spend.

Based on the information I feel that it is well worth the investment in either case to install the cooler as it will improve the engine life. In my case where I run the tractor 2-3 hours straight at high load I felt it was worth it.

On that note be careful how much you increase the RPM on the engines.
Usually the maximum is 3600 RPM for these engines but dependent on the application they are often derated down. I think Craftsman usually uses 3350 RPM.
 

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Funny...I work in a small engine repair shop and see most Command s that have a oil cooler on the side of the block..With only 6-10 lbs of pressure not sure you would see a large gain in engine life to over come the price..jmo
 

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Discussion Starter · #4 ·
I was told that spec speed on this tractor was 3200 RPMs, which is exactly where mine ran on the factory tach. I got interested in this because 2 people I know have commercial zero turns with Commands, and both SCREAM when wide open. The Dixie Chopper has a 23HP Command, and I found they run them at 3750. The Scag has a 27HP Command and doesnt rev quite like the Dixie Chopper did... my guess is around 3600. I have ours about 3500ish at the moment.

Supposedly one of the reasons for keeping the RPMs low on the Craftsman Commands was because of the residential limitation on blade tip speed. Sears choosing not to install oil coolers on them played a part too I reckon.

I dont understand the reason why oil pressure would matter. Anytime you get oil outside the engine to cool, its a good thing. There will be enough oil pressure for oil to flow through the cooler, and the airflow across the cooler is just a bonus.

This engine is a vertical also, so the cooler configuration is a bit different. Wonder if any body has messed with one like that?
 

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You can take the oil pump apart and stretch the spring in it and that will give you more oil pressure...my uncle has a pro built 18hp command thats pumping 90hp and 10,000rpms or more, and carries 50psi oil pressure... my stock 18hp command runs around 30psi and my 23hp runs 35psi when cold then drifts down to about 20psi(internals are wore so it loses pressure).....I believe the cooler is a good idea on a mower! and RPMS are safe to like 3800rpms for mowing....these command are a good motor I believe!!! BUT i do try and run mine at slower speeds when ever possible!
 

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I don't think pressure is a factor for the oil cooler - it's the amount of flow through it that matters.
Bypassing oil to go through the cooler might just deprive something else of oil, though.
Cooling oil is quite beneficial in hot weather, though, since a great deal of the engine's cooling is via the oil, not just the air over the fins.
 

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I didn't think an oil cooler was a BYPASS system????

Another cheap way, if you have the room, is to use a larger oil filter. it adds a few more sq. inches of cooling area to the "can" and a couple oz. more capacity.
 

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I didn't think an oil cooler was a BYPASS system????

Another cheap way, if you have the room, is to use a larger oil filter. it adds a few more sq. inches of cooling area to the "can" and a couple oz. more capacity.
I don't know, just made an assumption - not always a good idea :Stop:

Good suggestion about the larger filter. I do that with my Vanguard, both for cooling and hopefully a little more filtering surface.

I've seen an aluminum finned heat sink that clamps onto an oil filter. I bet that would help some.

J.C. Whitney used to sell them, but I did a search there and came up empty.
 

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The stock command cooler hooks on inline ahead of the oil filter, Id assume cause I dont own one that it just passes through it like a filter...Ive seen them but I dont use them on our pullers so Ive never really sat down and looked to hard.....
 

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Discussion Starter · #10 ·
The "better" factory Command oil cooler is a different oil filter adapter thats plumbed with two hoses coming out of it, leading to the cooler. A hole is cut into the engine shroud so it can pull air through the cooler. Here is a picture of the setup for reference-



This may be obvious, but on a vertical shaft engine the cooler lines run vertical and the cooler is mounted on the top/side of the engine shroud. On a horizontal, the lines run horizontal and the cooler is mounted at the middle rear of the engine on the shroud. With the cooler on a horizontal, it probably adds a little oil capacity.. not so much on a vertical.

There is also a more basic cooler that looks like this-



I do wonder if there are passages inside this one, or if it just acts as a large heat sink. If its just a heat sink, doesnt seem like a very worthwhile upgrade.
 

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The stock command cooler hooks on inline ahead of the oil filter, Id assume cause I dont own one that it just passes through it like a filter...Ive seen them but I dont use them on our pullers so Ive never really sat down and looked to hard.....
I installed the filter on mine which is similar to what is included in the kit shown. There is an adapter plate that goes between the block and the oil filter to divert the full flow through the cooler before it gets to the filter.
There is a spring loaded check ball that lets the oil go through the cooler before it goes to the oil filter.

The spring loaded ball ensures that there is still flow to the filter and engine in case the cooler is plugged up for some reason. This is pretty clever and serves the same purpose as the spring bypass on a filter. So the only potential downside to the cooler I can see is that there will be the slightest added resistance to the flow as it has a longer path now. Compared to the resistance in the filter it is insignificant.

Hope this helps.
 

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There is also a more basic cooler that looks like this-



I do wonder if there are passages inside this one, or if it just acts as a large heat sink. If its just a heat sink, doesnt seem like a very worthwhile upgrade.
I have seen but not used one of those.
It does have internal passages that lets the oil flow through the flat area of the cooler. I found my cooler of the newer style used for a good price and installed that instead.
 

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Ive always wanted to install the first cooler shown...Remove the stock lines and mount it off to the side on tractor and mount like an electric fan on it....YEs it would make it WAY more difficult for oil to flow....BUT we can do the oil pump upgrade for more pressure to ensure we get propper lube..Also a note, small block chevy hydrolic lifters are a PERFECT fit for replacing the stock kohler ones, will that aid in oiling the top end? I dont understand how the top end is lubed? SOrry if this is hi jacking this thread!!!
 

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Anyone attempted to add an OEM Oil Cooler from a Command to a Magnum (Vertical or Horizontal Shaft)?

I'm trying to find the Adapter Kit for this...

-Thomas (12)
Port Orchard, Washington

Sent from my SM-G900V using Tapatalk
 

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I don't recall exactly how, but maybe 6 months ago I found a Kohler pdf that listed a whole bunch of "options", such as air cleaner kits for cold weather, as well as oil cooler kits. You might try directly contacting Kohler to get this info, then with the part number, you can google for buying options.
 
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