Author Topic: WM drive belts on diesel engines (Read 2182 times)

barbender · « **on:** October 31, 2014, 10:13:31 AM »

I've been wondering something. My LT40SHD has the Lombardini 40 hp diesel, and a triple v belt (if that's the right thing to call it). It seems to me that the triple belt struggles to transmit all the HP without slipping when tensioned to WM spec. When gus are talking about getting 600, 800, 1000+ bf on one blade, I just don't get it, because I am usually closer to 400 bf (on clean logs with a semi functional debarker). My blades don't seem that dull, but I'm fairly certain the belt is slipping and causing wavy cuts. So what I'm wondering is, do the WM mills running the 50hp+ diesels run a 4 v belt? I saw Customsawyer mention in a post that he pushes his blades really hard and the tips tend to be rounded off pretty bad, so he has to sharpen his blades before setting. I could never push a blade in that shape on my mill and saw straight, the power just doesn't make it to the blade. To sum it up, I feel like I have a 40hp engine and a 20hp transmission

If I could get 2000bf out of one sharpening and saw straight lumber, I would happily push it until it just broke and put on a new one

backwoods sawyer · « **Reply #1 on:** October 31, 2014, 10:38:12 AM »

I am running the 42 hp Kabota.
The mill came with a two belt drive and I upgraded to the triple v belt.
What I have found is the stiffer triple v belt has a break in period before they wear in enough to set down in the groves to transmit full power and not chirp while idling. Once they wear in they chirp when the auto clutch engages and do a much better job of transmitting the power then the two single belt system did.

During the break in period of a new belt I have had to adjust the tension 2-3 times and the belts have been lasting about a year and a half. When they get worn down the belt rides on the ribs of shieve and starts slipping again.

If you have been running this same belt for some time with it slipping it may be getting time to replace it.

These belts were designed to be ran under constant tension, using them as a tensioner uses about half their life.
In the production mill all the edgers had these triple v belts on 100 hp electric motors. When you stick a cant in an edger they make a cloud of smoke rite quik like.

terrifictimbersllc · « **Reply #2 on:** October 31, 2014, 12:40:30 PM »

I have 42hp kubota, triple v belt, 1-1/4" bands 4, 7, 9, 10 degree. No problem with slipping that I am aware of, although it would take comparison of two tach readings engine vs. band wheels to be sure. Sometimes I get 1000 or more out of a blade in clean softwoods or small red oak but usually swapping out much earlier. Tension is 18 pounds at 7/16" deflection. Not sure how you know blade is slipping, if you think belt tension is the reason then tighten it considerably more when you are in the wavy cut situation and see if it improves the wave. You don't have to keep running it that tight, just as an experiment.

I never see power feed belt tension listed as related to waves but I firmly believe I've cut some wavy lumber because of a loose power feed belt in my younger sawing days. Suggest checking this. On my mill it is 7 pounds at 1/8" deflection, this is pretty tight.

barbender · « **Reply #3 on:** October 31, 2014, 01:25:10 PM »

Thanks guys, my belt probably only has 75 hours on it, and I have retentioned it several times (with the WM tension guage). I swapped out the old one because it was bottoming out like backwoods describes, maybe the new one just needs to settle in a bit. I was quite certain the old one was slipping, I could hear it (it wasn't a squeal, more of a low groan). Always in a wider cut. That improved right away with the new belt, buy I still hear it once in a while when pushing a slightly dull blade, and the sound always goes along wits a diving blade. I will have to investigate further

Magicman · « **Reply #4 on:** October 31, 2014, 01:34:44 PM »

Quote

with a semi functional debarker

Don't know what that means.

I vote for using the Debarker more and using sharp blades. Dull blades are forced backwards causing undue metal stress which shortens the blade life.

drobertson · « **Reply #5 on:** October 31, 2014, 01:36:40 PM »

Mine has the triple as well, it seems that 50 to 75 hrs is the time to re-adjust these belts. I don't have the gauge, but use the twist method. turn the switch to the acc mode and engage the auto clutch. then twist the belt. you should not be able to twist it to a vertical position. Not very scientific, but the way it was explained to me by one of the techs. A lil squawk when it engages .

YellowHammer · « **Reply #6 on:** October 31, 2014, 02:10:08 PM »

I also have a Diesel engine on my LT40 with the triple belt. I don't get any slipping at all when sawing, and I have come close to stalling the engine several times over the years when I get a little too happy with the power feed on a big hard log. I'm certain I'm getting all the engine hp to the blade. I use the WM belt tension tool. I have replaced the belt once due to normal wear, and have never noticed any slippage on the old or new one. I replaced the belt because of separation, not slippage.
YH

Will_Johnson · « **Reply #7 on:** October 31, 2014, 02:14:08 PM »

There are lots of reasons this may be slipping and for sure the guys at WM can help you through this.

But I think I can speak for them when I say: do not tighten the belt beyond their specs.

If you do this you will almost certainly get more power to the blade and faster cut speeds in the very short run.

In the medium or long run you will very likely damage, if not destroy, your engine due to excessive side-load.

(Keep in mind this is true of any engine and any mill -- I'm not in anyway saying this is a "Wood-mizer" thing. It's a physics thing.)

barbender · « **Reply #8 on:** October 31, 2014, 05:31:08 PM »

Quote from: Will_Johnson on October 31, 2014, 02:14:08 PM

There are lots of reasons this may be slipping and for sure the guys at WM can help you through this.

But I think I can speak for them when I say: do not tighten the belt beyond their specs.

If you do this you will almost certainly get more power to the blade and faster cut speeds in the very short run.

In the medium or long run you will very likely damage, if not destroy, your engine due to excessive side-load.

(Keep in mind this is true of any engine and any mill -- I'm not in anyway saying this is a "Wood-mizer" thing. It's a physics thing.)

Will, that is precisely the reason for my concern, and question. I do NOT want a busted crank. And I know that it is an issue, that's why WM has made the update available for the cat diesels to support the crankshaft.

Magic, my mill is a late '97 model, with the same frame etc as your mill, however, it has the "mark 1" debarker with the belt driven blade and 1/2 horse motor. It works, kind of

I mostly use it to remind me to wear safety glasses

Why does the debarker have to spin at the operator, anyways?

Dave Shepard · « **Reply #9 on:** October 31, 2014, 06:32:27 PM »

I have the 51 HP CAT with a triple v belt. I adjust it to the factory 7/16" @18 pounds. I have done a few full power passes lately to see what it will do, and I don't think there is any belt slipping going on.

customsawyer · « **Reply #10 on:** October 31, 2014, 07:22:41 PM »

Just for information. When I am talking about pushing a blade like that I have the best of all worlds. When I put a fresh blade on I use it to cut a couple of oak/hickory logs. Once it has cut those logs then I start putting sweetgum, sycamore or some other easy to saw wood on the mill. On the easy to saw wood it is all pallet wood, so if there is a little wave I don't stress about it. Just for the record I can't do with my other mill what I do with the one at the big mill. At the big mill I have plenty of logs to choose from and I am set up to cut what ever comes. I use this to my benefit. The few folks that have come down and seen the operation know that when it comes to my setup at the big mill, it don't get any better. Please don't use my numbers as a comparison for your mill, it will never measure up. I don't mean this in a ugly way, I am just saying that I can't even compete with that mill.

barbender · « **Reply #11 on:** October 31, 2014, 07:55:11 PM »

Jake, that would sound pretty arrogant if I didn't know what you meant

Thank you for clarifying how you get your bf numbers, so I'm not chasing something unattainable

This belt issue is something I've been pondering for a while, but probably won't look into for a long time. I still haven't got a chance to fix the hydraulic pump solenoid I posted about 2 months ago

It's really too much mill to be sitting around idle like that. I know because my wife keeps reminding me

I think she wants me to change it into something else, like say, $17000

drobertson · « **Reply #12 on:** October 31, 2014, 08:00:33 PM »

I can say with full confidence I have pushed my 40super to the max as well. no slippage, but the waves show up for sure.
and it is for this reason, and my little niche of sawing, I prefer to make the boards flat as possible. Now SYP knots really test my patience, but it boils down to it is what it is. A very thin band, with contrasting densities, I like pine, I really like red oak.

prittgers · « **Reply #13 on:** November 01, 2014, 09:50:46 PM »

Mike in WM Tech Support emailed me and mentioned that putting a thin coat of ordinary bar soap on the belts helps them to 'buff - in' to the pulleys. I'm going to try it on my next V-belt change.

Chuck White · « **Reply #14 on:** November 02, 2014, 04:05:26 AM »

Quote from: prittgers on November 01, 2014, 09:50:46 PM

Mike in WM Tech Support emailed me and mentioned that putting a thin coat of ordinary bar soap on the belts helps them to 'buff - in' to the pulleys. I'm going to try it on my next V-belt change.

Like we used to do on the old cars when we had a squeaky fan belt!

petefrom bearswamp · « **Reply #15 on:** November 02, 2014, 08:36:14 AM »

Mine is the perkapillar 51hp and I get an occaisional squeal when the auto clutch engages.
I attribute any waviness to my sometimes incompetent sharpening.
I saw 95 percent hemlock and the knots are a problem.
I cannot get the high Board feet per blade some are claiming, about 4- 500 ft. in a good day.
I use 7 degree hook angle.
My blades are a mix of WM Cooks and i now have 2 from the guys in St Louis.
I used to some TW also with good results.

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