2554 heat shields and underhood temps.

[JSharp]

Ok folks, here the temp readings I took last night as promised. I used my Rayek MT-6 IR thermometer again for the surface temps of the oil filter, oil cooler, and heatshield. I wanted to get some better air temperature readings under the hood while running so I used a Fluke model 52 for those with two bead type thermocouples. The Fluke will record and hold peak readings and was set to do so. The thermocouples were mounted as follows -

One thermocouple was mounted about 1" from the front of the air filter housing, slightly off center. This should give us a good idea of engine intake air temperature and the overall underhood temp.

The other thermocouple was mounted near the bottom of the PTO clutch, about 2" away from it in the cooling airstream that exits the heatshield. This the engine cooling air after it passes over the muffler and the clutch.

I mowed a little over an hour in 85ºF weather. Grass was tall but not wet. In my estimation an average amount of engine load as I could tell later. Here's the peak numbers but keep in mind they aren't just some rare and seldom seen peaks. The air temp measurements ran up to within about 15ºF what I recorded as maximum after just a few minutes of mowing -

Intake airstream - 174ºF
Cooling/clutch airstream - 236ºF

The next three are surface temps and were taken with the Raytek immediately after stopping. I stopped, set the engine to idle, got off, opened the hood, and shot the temps -

Oil filter - 255ºF
Oil cooler - 267ºF
Heatshield - 215ºF

All I can say is WOW. These numbers are WAY too high IMO. Clutch life is going to be a ? and the intake air and oil temps are disturbing.

To comment on the engine load having an effect, it does. I could see the cooling air temps climb after a little lag while going slow in heavier grass. Then they'd fall as the load was removed. And when I ran just the deck wash later with the tractor parked I never did see the cooling air temp above 200ºF

I gotta run right now. I've some other comments I'll make later today, but there's the numbers. Enjoy...

 

[TractorLarry]

Good Heavens!

-Larry

 

[JSharp]

Larry wins the understatement of the day award.

I called Kohler a bit ago and talked to tech support. Nice guy they connected me to. I gave him the temp numbers I got and although he wouldn't make any comment either way on engine life he did say he'd seen this sort of thing before. He also said "Those tractors companies don't seem to pay enough attention to cooling" and that he "wished they would."

I asked him about the clutch but since they don't build it his only comment was "they should have tested it and determined if the environment was acceptable."

I guess everyone can decide for themselves what Cub did or did not test. I know what I think. Does anyone know who builds the clutch assembly? I'll call the manufacturer if I can find out who they are.

I have to agree with all that like the old 2500 series metal hood setup. I don't care for the Mickey Mouse collection of levers, hinges, panels, fasteners, etc. but I'm sure it's far superior from a cooling standpoint. That much is obvious from even a casual glance.

I have some things I want to try on my tractor to get these temps more in line with what I think they should be. I left the thermocouples attached so I can connect them right up after I make some changes.

I hope all of this is of some value to people. Certainly those that have gone though the whole melting hood saga on their tractors might be interested...

 

[Northstar]

JSharp
I was wondering can you check oil temp. or does anyone make a oil temp guage for Kohler engines? I have a Harley (air cooled) , with synthetic oil it runs 200-220 degrees. Thats running at highway speeds, I wonder what the norm is for a tractor? The readings your getting seem way to high, esp, at the oil cooler.

 

[JSharp]

JSharp
I was wondering can you check oil temp. or does anyone make a oil temp guage for Kohler engines? I have a Harley (air cooled) , with synthetic oil it runs 200-220 degrees. Thats running at highway speeds, I wonder what the norm is for a tractor? The readings your getting seem way to high, esp, at the oil cooler.

I have to agree. They seem way too high to me also. That's what got me started on all of this. I'd thought for a while that my tractor ran warm, then thought to check after seeing some numbers posted on a different board from a single cylinder Kohler. He also took them with an IR thermometer.

I don't have a way to measure the oil temp directly though, just the IR gun measuring the filter or cooler temp. Too bad my oil cooler sandwich adapter doesn't have a port for an oil temperature sender. That would make this easier. The guy at Kohler didn't seem surprised though.

I don't how the surface of those objects could be hotter than the temp of the oil inside them though. The oil filter maybe since it's tied to the engine with a metal center tube that could conduct heat to the filter. But the cooler, it's mounted to the plastic shroud and connected with rubber hoses. The only heat that it can absorb is from the oil plus maybe a small amount of radiant heat from the engine.

Your Harley has adequate cooling air moving across it on the highway and a larger capacity dry sump oiling system. That certainly helps.

We've sort of come full circle. My contention is still that we don't have sufficient cooling in this application and that's what these temps show...

 

[GreenQuality]

Good work! J-sharp the clutches are made by warner! Carpet cleaners ran in to the same problems. engine being inside a vented van can still get the engine hot what they did may shock you! but worked thay placed there oil coolers with cooper tubing into a bucket of water which cooled the oil and brought the temps down.

 

[JSharp]

Northstar, you got me wondering if using my IR thermometer on the oil filter was really a good way to measure oil temperatures. So I checked my 5.0L Mustang this AM after my 20+ mile trip to work.

80ºF day today. The car has a 192ºF thermostat and I ran all the way with the air conditioning on. For sure the thermostat is open.

Top radiator hose near the thermostat housing - 196ºF
Oil filter - 221ºF

I'd expect to see the oil temp within 10-20ºF of the water temp as long as the engine wasn't run hard or with a high load. It's showing a bit above that. But in this case the oil filter is just a few inches from the left header that reads 653ºF so the filter may be getting some radiant heat.

Anyway, the previous numbers from my Kohler *might* be a little high although I don't know for sure why they would be. But even if we knock off say 15ºF from them we're still into an area where I don't think we should be. I'll be checking them again so we should be able to see if the measurments have any repeatability...

 

[JSharp]

Good work! J-sharp the clutches are made by warner! Carpet cleaners ran in to the same problems. engine being inside a vented van can still get the engine hot what they did may shock you! but worked thay placed there oil coolers with cooper tubing into a bucket of water which cooled the oil and brought the temps down.

Thanks for the clutch info. I looked at the Warner site but unfortunatly they don't have much technical data there past the mechanical and electrical specifications. The do say their "Lawn and Turf" clutches are made to survive "typical undehood temperatures." Whatever that means.

I'll check mine for a number when I get a chance and then I can call and see if I can get the rest of the data. I have to think it's a question that's been asked before...

Hey, that container of water cooling method worked on machine guns as far back as WWI.

 

[Northstar]

JSharp,
I believe the most important reading would be the oil temp itself. Regardless of melting hoods or anything else if the oil fails we have a major problem.I was on Kohlers website tonight looking for a oil temp guage and found some interesting things. First they have a " High Temp Cutout Switch" . This sounds like a safety device for the engine. Second and most interesting is the " Oil Temp Sensor" . They have two , the first opens at 310degrees and closes at 350 degrees, the second opens at 255 degrees and closes at 310 degrees. These temps seem pretty much in line with the readings you have been getting. I think what we need to know is what is the normal oil temp ? I found some aftermarket temp guages and if I can find the right one for a Kohler engine I will be hooking one up. Thanks for all the ground work and research you have put into solving this problem and should the problem arise this winter Kohler also has Anti Iceing Componets

 

[Fordlords]

During this weekend I will take some temp readings in the same areas on my older Cub with the new Honda engine for comparison. I will use my Extech thermocouple thermometer for the tests. This might help us determine if the engine temps are a cooling system design flaw with the newer Cubs, or if most of the horizontal engine cooling systems run in the same temp range.

My Cub has its original Warner Electric PTO clutch, now 26 years old. But as you can see in my engine photos, the ductwork blows the air upwards and away from it, as it did with the original Kohler KT engine which had iron cylinder jugs and probably ran 30-40 degrees warmer than the Honda does as was common with cast iron engines.

-Fordlords-