The Forestry Forum

General Forestry => Forestry and Logging => Topic started by: Chris-M on August 11, 2021, 06:58:08 PM

Title: Terex PT-100 + Mulcher - roof top cooler
Post by: Chris-M on August 11, 2021, 06:58:08 PM
I am new to the forum, so hopefully I am posting in the right area.

Previous Equipment: For a year, I cleared yaupon/brush lots with a Bobcat T-190 skid steer and a rotary cutter MTL XC7 (60" 2 blade cutter). This was a low-flow rig. I used the grapple to pile up all the debris and burned it.

Current Equip: I sold the Bobcat and now have a 2008 Terex Forestry PT-100 carrier (100 HP) mated to a 60" Bradco MM60 mulching head (with 44 steel claw reversible teeth). The Terex has 1,800 hours on it. Hours on the mulching head unknown, but looks in good shape. I have new teeth on the mulcher.

What I do: I have a full-time job and do lot clearings on the side. I probably do 3-4 Jobs per month – so I am definitely not full-time into land clearing, and am not looking to quit my day job either. I do enjoy land clearing, so it is an enjoyable way for me to make side money.

The land I am working with: I mainly clear lots with yaupon, brush, and small trees, cedar, etc. I don't do large trees (6-7" diameter plus). I refer large tree removal to a buddy of mine; that's all he does – tree work. The soil where most of my jobs are is sandy or a sandy-loam mix, no rocks in the soil to speak of. Some of it is lot clearing and some of it is just brush cleanup around people's houses. This is a rural area, and the neighborhood I have 95% of my jobs in is rural; a 4,000+ acre development with lakes etc - kind of a resort neighborhood, but in a very rural setting. Some of the lots are hilly but most are flat or have slight slopes.

My issues and question: My Terex has a high flow system pushing 36gpm at 3,000 psi. When using the bucket, my machine never gets hot. Mulching, in Texas summer heat (90ºF plus temps outside), I can mulch heavy brush and yaupon for about 45 minutes and then need to let my machine cool for 10-15 minutes. When my machine gets above 190º I shut down to cool. If the land is very hilly it starts getting hot sooner than 45 minutes.  

1) Is this normal, to have to stop to let the machine cool down after about 45 minutes of mulching in Texas heat?

2) Would a roof cooler (hydraulic oil cooler) make it to where I could run without having to stop and cool the machine?

3) I know my machine is far from new, but would a brand new carrier of similar HP still require a cooldown in 90ºF heat, assuming no roof cooler?

Title: Re: Terex PT-100 + Mulcher - roof top cooler
Post by: treemuncher on August 11, 2021, 08:41:29 PM
If you are shutting down when the engine temp is 190 degrees, you are wasting your time. Today's diesels often run at 210-220 degrees on a hot day, not that I ever like seeing anything over 215. A solid cleaning and straightening of the radiators is part of regular maintenance with these machines. Sometimes I spend 2-3 days to clean and straighten core and fins on just a single machine as part of regular maintenance if needed. It can make a huge difference in cooling efficiency. If you can't see light throughout the entire radiator surface when lit from behind, it needs cleaning.

If a machine is getting hot, drop the load, park it and idle it around 1200 rpm until temps get back to normal. Shutting it down won't allow the radiators to do their jobs.

If your hydraulic oil is 190 degrees, yes that is too hot. Any restrictions in the system? A thermal camera could help diagnose this. Are you trying to run too much flow to the attachment? Some attachments can't handle what the machine can provide. Skid steers are not forestry machines and from what I've seen, they will always overheat when put through that type of service. You can run the pith out of it with a bucket and stay cool but the demands of a cutter are totally different as the engine is almost constantly loaded and generate lots more heat.

A local equipment company called me a couple years ago regarding a new skid steer that was overheating when using a brush cutter. They could not figure it out and wanted my help but I was working distant. I think they finally installed an additional cooler to solve the problem.

Mulching heads tend to draw a lot more hp than rotary decks from my experience. They also do a lot more work. My solution to my Posi Trac problems was to sell it off and purchase a true forestry machine. A proper built machine can be completely clogged looking on the screens and still be in the green on the temps. What was 2.5 minutes with 105 hp Posi became 30 seconds at 140 hp on the forestry machine without any overheating issues.
Title: Re: Terex PT-100 + Mulcher - roof top cooler
Post by: Walnut Beast on August 12, 2021, 02:42:24 AM
Definitely make sure you have everything cleaned out really good. What is your reversing fan set at ? Set it lower. Are you running carbides or knives on the mulching head. With that power it would run way more efficiently with knives. Do you have a bite limiter. Most  skidsteers are not designed for mulching as previously stated. Go to Mulcher Mafia and find out which ones burn to the ground and overheat all the time. The ASV is absolutely built for mulching and the ASV RT120F is a beast and the best out there.... That’s why Vermeer has it rebranded in there lineup of mulching machines with a Fecon head on it. Many many guys running dedicated machines along with skidsteer mulcher setups. I know multiple guys running 4 ASV 120F units with Prentice wheeled mulchers and 30 ton excavator mulchers. Dedicated machines are great. But they do have there share of problems. Steel tracks are not maintenance free. 1000 hrs and it’s time on a dedicated mulcher 
Title: Re: Terex PT-100 + Mulcher - roof top cooler
Post by: kiko on August 12, 2021, 10:34:39 AM
Often there is a manifold in the mulcher head that has a relief valve or even a flushing valve.  If the relief in the manifold block is set /or failed to a lower pressure than the machine system relief, it will generate excessive hydraulic temps and load the engine more  than normal.
Title: Re: Terex PT-100 + Mulcher - roof top cooler
Post by: barbender on August 12, 2021, 10:37:35 AM
Get yourself an infrared heat gun if you don't have one already.
Title: Re: Terex PT-100 + Mulcher - roof top cooler
Post by: Walnut Beast on August 12, 2021, 11:14:13 PM
Make sure your temperature sensor is not bad. Is your coolant level ok. Most guys running in the Texas to Florida heat are running all day long in solid dust and heat at tops of 140 to 155 and a few are on deleted 120s with 50g min. at 4500 psi. You are definitely running to high. ASV has the best cooling capacity by far. Let us know what you find out