2550 Melting hood!

[Fordlords]

Here are generally acceptable temperatures for air cooled aluminum engines. These are not specific to any perticular engine, just general ranges with engine at operating temperature.

Oil Temp: 180-210 degrees, 230 degrees max. (This figure is most important, as overheated oil is what will damage bearings)
Cylinder Head Temp: 300-385 degrees, 450 degrees max.
Exhaust Gas Temp: 1000-1200 degrees

Now as for what Cub actually engineers or uses as acceptable figures, I have no idea. I have yet to hear of any issues involving overheating or engine damage with the Command engines in any year model of Cub 2500, or actually any model of Cub, ever.

Thermoformed plastic hoods? Simply put, they suck. They are used not because of scratches or dents, they are used to cut costs. They probably cost $10 each to manufacture, where a metal hood probably costs $50 or more between material, stamping, and finishing. That's $400,000 in savings on a run of 10,000 tractors. In essence your sucky hood pays for that new carpeting in the CEO's office and a really lame summer picnic for the employees with thermoformed coffee mugs as door prizes No matter what color it is, it's all the same.

-Fordlords-

 

[Dascro]

Got a question on my 2007 2550. The louvers in the hood are all open. Is there another "panel" in the center of the hood that can/should be removed to aid cooling air flow?

Also, while I haven't paid particular attention up till now, I can't say that the engine temp on the 2550 seems any hotter to me after mowing for a couple hours than on any other air cooled engine I have used in the past.

I have rebuilt and used old Cub Cadets up until I bought this 2550 (128 and 1650), and the air flow is exactly the same on the 2550 as it was on both the 128 and 1650. I do notice more debris on the 2550's screen though. But I also blow it clean after each use with a leaf blower.

Lastly, I have noticed that the air filter gets real dirty real fast (at least the pre-cleaner)!! But I have attributed that to the very dry conditions here and the amount of dust in the air during mowing. I'll have to watch that over time.

Anyhow, if anyone can enlighten me on any other louvers in the hood of my 07 2550 that can/should be removed, I'd appreciate it.

Dave

 

[Dascro]

Later this morning I got a chance to check the hood on my 2550 and answered my own question on the center hood louvers . There is a cover over the louvers.

But this leads me to another question. What is the best way to remove the fasteners on the pegs of the cover to allow the cover to removed?

Thanks,
Dave

 

[JSharp]

Here are generally acceptable temperatures for air cooled aluminum engines. These are not specific to any particular engine, just general ranges with engine at operating temperature.

Oil Temp: 180-210 degrees, 230 degrees max. (This figure is most important, as overheated oil is what will damage bearings)
Cylinder Head Temp: 300-385 degrees, 450 degrees max.
Exhaust Gas Temp: 1000-1200 degrees

Now as for what Cub actually engineers or uses as acceptable figures, I have no idea. I have yet to hear of any issues involving overheating or engine damage with the Command engines in any year model of Cub 2500, or actually any model of Cub, ever.

Thermoformed plastic hoods? Simply put, they suck. They are used not because of scratches or dents, they are used to cut costs. They probably cost $10 each to manufacture, where a metal hood probably costs $50 or more between material, stamping, and finishing. That's $400,000 in savings on a run of 10,000 tractors. In essence your sucky hood pays for that new carpeting in the CEO's office and a really lame summer picnic for the employees with thermoformed coffee mugs as door prizes No matter what color it is, it's all the same.

-Fordlords-

That earlier post of mine wasn't meant as a dig on you Fordlords, it was dig on the guys at Cub. I noticed a year or so ago when I first came here that you were one of the straight shooters on the board and knowledgeable. Maybe I should have used a few more in there somewhere...

Your listed temps are right in line with what I've always been told. Of course air cooled engine temps will rise on a hot day with high loads and fall on a cool day with light ones. But there are some upper limits as you've said that should be approached with caution.

Judging by my earlier 238ºF measurement on the oil filter end cap I think these things are pushing it. And it's my belief it's because of the inability of the cooling fan to pickup anything but already heated air.

I think we'll see reduced engine life on the plastic hooded 2500's vs. the previous ones thanks to this whole cooling issue. They're just too new yet to have anyone with enough hours racked up to notice. Time will tell.

Unfortunately the fix here may involve even more plastic. Something like a divider in the engine compartment or some other means of ducting cool air to the engine fan and separating it from the hot hair under the hood.

I'll see what the dealer says tomorrow, along with writing notes to Kohler and Cub. The GF and I talked last night and we both realized I'm going to take an absolute bath on this thing if I get rid of it. The dealer I got it from sells Case/IH, Cub and Grasshopper so they won't be able to offer me anything that might better. I like the additional features of the 3000 Series but I'm a bit sour on Cub at this point and the turning circle on one would be a problem in my use. And trading at the other local dealers that sell other brands I'm unlikely to get more than 1/2 of what I paid a year ago, if that. $2000 is a lot to lose for such short hours.

Buyer beware indeed...

Dascro - I'm glad you found the cover fasteners but don't expect removing the cover to do much. There seems to be little to no airflow in that area of the hood...

 

[TractorLarry]

Is it possible to send the exhaust parts out and get them coated with that ceramic stuff they use on car headers? From what I've read, it does a heck of a job keeping the heat in the exhaust system.

-Larry

I thought it was excessive myself.

The cooler is located on the shroud. You cut a rectangular hole in the shroud and mount the cooler to it. Then the engine fan blows cooling air through it. I'll see if can find a photo or take one if I can't. It has a massive amount of air blowing through it. Too bad it's the hot underhood air that the engine fan picks up instead of some cooler outside air...

Those temps I measured are telling us something about the oil temps and IMO they're plenty high. It certainly doesn't make me want to run inexpensive oil.

That might also explain why the Cub Cadet oil change interval is 1/2 ( 50 hours vs. 100 ) of what Kohler recommends in their engine manual...

There's a stainless steel guard over the muffler but I like the header wrap idea. That stuff always shortens header life but if it extends engine life it might be a good trade off...

 

[TractorLarry]

Is there anything about the 1864 I should be aware of?

-Larry

 

[Fordlords]

I'm curious if the way the 2006 2500's duct air is different than with previous horizontal engine Cubs.

The 682 I have ducts like any other Cub I have seen- cool air enters from underneath the tractor, right above the center of the deck where the drive shaft tunnel is. There is a metal screen there to prevent large debris from entering. I would figure this air to be fairly cool, and at least as clean as the air anywhere else around the tractor while mowing. It then goes through the "firewall" in to the engine fan, which is butted up to the firewall. It then exits off the engine shrouds, over the exhaust system and muffler, (which are also shrouded) and out through the front of the tractor which is a fully open grille and perforated metal section by the headlights- essentially wide open, but the heat is ducted upwards.

Where is the 2006 2500 actually drawing it's outside air from?

One thing I remember is the cooling air exit is supposed to be at least 4 times the area of the inlet air opening. On the 682, I'd say this is pretty close. I have had no concern for the Honda engine running too hot.

There may well be some mis-engineering on Cub's part with the 2006's that only time will tell if engine damage will occur. The melting hoods do tell me they are running the plastic hoods way too close to hot components, or are using materials not made to withstand the temperatures- all things that should have been recongnized during the initial development and testing of the design. Perhaps it's going to come back and bite them.

-Fordlords-

 

[Dascro]

I understand why others have serious concerns in regard to cooling air flow on the 2500 series tractors. And I am not arguing with those that have experienced problems with their hoods because of temperature. I have about 20 hours on mine and so far, so good.

But I am having a hard time reconciling the difference in airflow patterns from any other older Cub Cadet I have owned or seen (and older John Deere 140's too) with the air flow pattern on my 2550. And the fact that the side of the hood is open at the cooling air intake location adds to my question .

More to the point, I don't understand where such overly hot air would be coming from to be drawn into the cooling air intake? All airflow principles just seem to counter hot air build-up in that area. I can see it being warmer than ambient, but not that much more. Again, I am not challenging anyones experience or measurements. I'm just having trouble seeing how cool ambient air would not enter into the cooling air intake area.

Maybe its just that the plastic hood is too close to the engine?? Not that the engine is running too hot?

If I am missing something obvious (and it wouldn't be the first time ) please help me understand why the problem is engine heat and not the plastic hood too close to an aircooled engine.

Thanks,
Dave

 

[CCinCT]

The air is drawn in from a grill below the steering wheel and above the drive shaft, and from both sides of the rear engine compartment (basically above the driver's feet). The air is blown forward and exits through the front grill as best I can tell. I haven't put a thermostat to the oil filter or the engine compartment, but I've never felt any kind of heat anywhere that would make me concerned about longevity.

 

[Dascro]

Yeah, I agree CCinCT.

After dinner tonight I did a rudimentary, yet credible (I believe) smoke test inside one of our bigger buildings that can provide a still air environment (I was in there finishing up some work anyway and figured what the heck!). What I found confirms what you just stated. In fact, I found that the engine draws in ambient air from about 4 inches away from each side at approximately 1/2 throttle.

And while I haven't measured any temperatures (and probably won't) I am now less concerned based on my smoke test and my "feel" that this engine doesn't seem to run any hotter than any other air cooled engine I have used over the years.

Time will tell, but I feel pretty good about engine longevity. Plastic hood life may be a different story!

Dave

 

[JSharp]

Well, I tried to mow today. I got 3 passes and noticed the left rear deck wheel laying on the ground thanks to the shoulder bolt/axle breaking. I figured I'd run the deck wash anyway and noticed one headlight out and the other one flickering... More for the dealer to fix when they come pick it up. I'm done fixing things for the 2 remaining years of my warranty. I've already done a number of repairs on this mower not limited to the POS press in zerks and straightening out the steering wheel after the steering recall.

Here's a few photos for those not familiar with how the '06 2500 series is setup. You can see the oil cooler I added to the Kohler and see that there no ducting of any kind to the engine cooling fan inlet.

It just draws air from where it can and sends it over the engine after exiting the engine shrouding. No ducting in, no ducting out. No control of airflow at all and no way to keep the hot underhood air from being drawn back into the cooling fan or into the engine intake.

What we have here in effect is a heat source with fan, the engine, and an almost closed "box" that is the hood. Opening the lower rear sides of the box and adding a few louvers to the top of it doesn't change the fact that there's not enough air actually being forced through the box by the cooling fan with no ducting arraingment nor does the cooling fan or carb inlet have direct access to cool air. They just pull in whatever is under the hood. And if that's hot re-circulated air, then that's what they get. Ultimately some gets out of course. We see that in the burned spots on our lawns. But judging by the temp readings I've taken, it's not nearly enough IMO.

Folks are free to believe my temp readings or not. They're as real as they can be. They were taken with an almost new Raytek MT-6 IR thermometer and an older remote thermistor thermometer made my Computemp. And I've been designing and implementing instrumentation since the 70's so I do have some idea how these things work.

One thing I'm pretty sure of though - The *many* folks that have had hoods melt and the others that are already seeing high oil consumption at low hours are likely to believe me...

 

[CCinCT]

Your last photo does a great job of showing where most of the air is drawn in from, for those that aren't familiar with the hood. Why you keep insisting that hot air is being drawn DOWN from the engine compartment is beyond me, but whatever. I've had no problems with cooling, nor has anyone that I know of in the area.

I'll snag a temp gauge in the next day or to and see what I get for temps at the same locations you measured at.

 

[JSharp]

I was going to ask you a similar question. Why do you insist that air flows from the louvers under the steering wheel when there are 2 steering system cover plates in the engine compartment that almost completely block that area? I'll post some pics of that area being blocked if you like but anyone with a 2500 series can see them.

I can also post another photo if you like that shows just how enclosed the engine really is. The vast majority of it, where the cooling air actually exits the engine shrouds, along with 100% of the hot exhaust system, is under the hood. But again, anyone who's seen one can see all this is true so there's little need to post more pics.

I'm not insisting that air flows just downward. I'm insisting that heat builds up under the hood since there's no real mechanism I can see to prevent it. Then the engine fan and intake can draw that hot back into and over the engine.

I'm also insisting that oil filter and and sump temps of almost 240ºF to almost 250ºF are TOO HIGH for a lightly loaded engine on a 90ºF day. Especially when that engine has an additional oil cooler.

Anyway, those numbers may look just peachy to Cub Cadet dealers and the factory "engineers", but they don't to me. And my hood agrees...

 

[Fordlords]

Now that I see the picure, what is wrong with that? It's got a wide open area on both sides of the tractor, right by the fan, to draw in fresh air- adding ducting there would not help it any. The warmer air under the hood will rise to the top. If you are concerned that the fan can draw in some warm air in from the top, yes it can, but these type of tractors have been doing that for ages. Some warm air gets back in, it's not a problem.

I don't know of any lawn tractor out there that has a fresh outside air draw for the intake or carburetor.

I don't think the ducting on my older Cub works better, if anything I'd say it would be worse. I can take temperature measurements with my Extech thermocouple thermometer if we want to compare. One thing I know is worse is the screen under the tractor with my setup has to be cleaned, and it is much harder to get at than having the fan shroud right there up top easy to clean. These have to be cleaned on every air cooled lawn mower engine every few hours.

Looking at the 2006 setup in those pictures, I really don't see what is wrong with it. The plastic hood is just the plastic hood doning the things that plastic hoods will do. See the dealer, get the mods and the problems repaired. You put on the oil cooler, so you are doing the best you can do to keep it as cool as possible, you might just be worrying too much.

-Fordlords-

 

[JSharp]

I'd agree with you Fordlords had 2 things not happened in the last week. I was playing around with my Raytek and noticed what I thought were high filter and sump temperatures. Then I noticed my melting hood...

<shrug> I'll call the dealer in the AM. They can come get it and can replace the hood along with everything else that's broken on the tractor right now. If they fix those things enough times, maybe it'll motivate them to do something different in the future...

 

[Fordlords]

This is what the "ducting" on the 682 looks like, with an engine that really is completely boxed in. All air is drawn in from underneath, and ducted out front. Kind of makes you more comfortable with the 2500's now, I hope

-Fordlords-

 

[CCinCT]

JS, in this quote:

Quite a bit of "sag" around the the hole cut for the exhaust pipe and the grill is looking bad.

... you point to the hood melting around the exhaust. This is a know issue with the latch failing, not with a cooling issue. The latch fails and causes the hood to ride higher than normal, partially (or coming very close to) blocking the exhaust. which would cause any hood to melt. This would also result in much higher engine compartment temps, and eventually higher oil temps. Is it possible that this is what's going on?

If your latch has indeed failed in this manner, than it's also probably that you don't have the additional exhaust shields in place, These two things would explain why your experience is different than mine. Mine was made in early '06, but my dealer has performed all TSB's that have been issued, at least that I know of. I don't have any unexpected heat build-up, and I don't get brown grass even after letting my 2544 idle at full throttle for 15 minutes (which I did yesterday because of this thread, just so I could see firsthand). The only thing left to check is oil temp, which hopefully I can do this week.

 

[JSharp]

JS, in this quote:

... you point to the hood melting around the exhaust. This is a know issue with the latch failing, not with a cooling issue. The latch fails and causes the hood to ride higher than normal, partially (or coming very close to) blocking the exhaust. which would cause any hood to melt. This would also result in much higher engine compartment temps, and eventually higher oil temps. Is it possible that this is what's going on?

If your latch has indeed failed in this manner, than it's also probably that you don't have the additional exhaust shields in place, These two things would explain why your experience is different than mine. Mine was made in early '06, but my dealer has performed all TSB's that have been issued, at least that I know of. I don't have any unexpected heat build-up, and I don't get brown grass even after letting my 2544 idle at full throttle for 15 minutes (which I did yesterday because of this thread, just so I could see firsthand). The only thing left to check is oil temp, which hopefully I can do this week.

Mine is also early '06. I would have done the TSB before except I didn't know about it. It's not like Cub sends out notices.

Here's a photo of what mine is doing -

My latch is fine but it won't be soon since the whole front of the hood is starting to deflect. And though it's not easy to see in this photo, the exhaust pipe is still centered in the hole through the hood and protrudes slightly.

You can see in the photo where the lower part of the hood is starting to twist and deflect downward, pulling away from the grill. On the inside you can see ( not in these pictures though ) where the grill is also deflecting. What would help here is a longer exhaust pipe but, it's not possible because then the hood wouldn't open.

In the first pic you can notice too how the headlight reflectors are sagging and the lenses are turning white already. 1 year old and always garaged so it's not in the sun except when it's being used. That doesn't bode well for the longevity of the headlight assemblies either.

I'm liking Larry's header wrap idea more all the time even after they fix all of this stuff with the latest factory scab-on.

I must be lucky since mine got it all. High oil temps, brown grass, and now a melting hood...

 

[JSharp]

This is what the "ducting" on the 682 looks like, with an engine that really is completely boxed in. All air is drawn in from underneath, and ducted out front. Kind of makes you more comfortable with the 2500's now, I hope

-Fordlords-

Check out a current 3100 if you get a chance. It has a sealed engine fan inlet sized flexible duct that ties to a plenum under the steering column. That plenum has a screen below the dashboard as it's inlet.

It's really done right. Nothing but cool outside the engine compartment air makes it into the cooling fan.

Nice tractor by the way. I've liked it and the Honda engine retrofit since I've been here.

 

[nbtvee6]

Have you considered the possibility that the engine may be running lean? A lean running engine will run hotter... Just an idea....