Air Filtration for the PT

[smartguyz]

Hi Guys,

I was out using the brush hog for about 4 hours today, and of course the PT425 was just filthy afterwards. Some detergent, pressure washer, and the handy-dandy leaf blower got things spic and span again, but I was wondering...

Has anyone considered the notion of providing filtration for the engine bay? For example, the engine cover could be sealed at the bottom (where it contacts the chassis), and the holes at the bottom of the chassis could be covered. The openings in the engine cover could be covered with filtration material - perhaps furnace filters. The idea is that the unique design of the PT could lend itself well to an easy-upkeep design, where all you do is either clean or swap out the furnace filters. The key would be is there is sufficient airflow into the engine bay to keep the Kohler cool. I would reckon that if you keep an eye on the filters, you could always take a quick break and then swap the filters if need be. I'd be willing to bet that, assuming sufficient air flow, this would be a wonderful way to keep the job of keeping the PT running cool and clean - and make cleanup really fast.

A few minutes with a garden hose would be all that would be need to keep the rest of the unit clean.

Any thoughts?

-Rob /forums/images/graemlins/laugh.gif

 

[Bob999]

I have given it some thought because on my unit the engine "radiator" on the Deutz engine tends to plug up from chaff with resulting overheating. I presently have the back of the unit covered with screen material that is simply taped on. This dramatically reduces the amount of material going into the engine radiator and takes care of the overheating problem. I am considering a more permanent sulution of using perferated metal with 1/16 " perferations. I believe that this material will clean up much more readily that screen based on experience with this material on a skid steer. This material has an open area of about 40% and I believe will provide adequate circulation -- provided that I cut holes for the engine exhaust and for the cooling air exhaust from the engine.

 

[Charlie_Iliff]

I've gone the same route as Bob, but put insect screen over both sides and the rear. I can now mow for two hours without overheating instead of ten minutes.
I have a centrifugal filter to mount to the back but haven't yet tried it.
I'd vote for insect screen rather than furnace filter to try first. I just taped mine on with duct tape pending test results and a more elegant solution. It's still on there after ten months.

 

[smartguyz]

Wow, Charlie - You overheated after 10 minutes? That's pretty severe. What are the symptoms that you notice? Does the 1845 have a temp gauge?

-Rob /forums/images/graemlins/shocked.gif

 

[Charlie_Iliff]

There is a considerable amount of discussion, including some pictures, about the 1845 overheating problem in threads last summer. It happens in high-chaff mowing where the chaff packs into the oil cooler of the Deutz. Since the engine is oil cooled, restriction of flow causes fairly quick overheating. I reduced the problem dramatically by enclosing the compartment with screen. Sedgewood had similar good results with a frame inside the engine compartment holding screen over the cooling fan.
I don't think there is a similar problem with the 400 series, but our screen experiments showed that with screen over the cooling intake there wasn't enough restriction to cause overheating. I would guess the 425 would also still get enough flow if some screen were taped where you have clippings being sucked into the engine compartment. I've not heard of any overheating in the 400 series.

 

[Bob999]

The 1845 does have a temperature gage--it is liquid cooled. A concern I would have with the 425 is that there is no temperature guage and you may not know if there is blockage until it is too late. I think frequent checks of the screens on the engine and, if you have the Kohler Command Pro, of the oil cooler coil on the engine would be prudent.

 

[SnowRidge]

<font color="green">( A concern I would have with the 425 is that there is no temperature guage and you may not know if there is blockage until it is too late. )</font>

I think that is a valid concern, and I would love to add one if I can figure out how to do it neatly and without invalidating the warranty.

SnowRidge

 

[smartguyz]

Agreed, Snowridge.

The PT is a major investment, and I'm doing my best to keep it a lasting one. Has anyone put in a temp gauge on a PT425?

-Rob

 

[Bob999]

I have never seen temperature guages for small utility air cooled engines. The first issue is what do you measure--head temperature or lubricating oil temperature. I know that air cooled aircraft engines include head temperature sensors. Unfortunately this is a very specialized and expensive market to try to buy parts from.

The Deutz engine used in larger PT units is oil cooled (using the same oil as for lubrication) and the temperature guage is measuring the oil temperature

 

[SnowRidge]

I did a little investigating.

VDO sells temp gauges for air cooled engines. They are popular with karters and VW bug enthusiasts. The sender is a thin ring shaped transducer that replaces the spark plug gasket. I don't know if they make one for the plug type used by the Kohlers (didn't get that far).

Kohler sells a temperature sender themselves that replaces one of the oil drain plugs. It is a switch type that is designed to turn on a red light. I will probably go that route, but will hook it to a <font color="red">LOUD</font> bell instead.

SnowRidge