Circular mill power unit

[Osterman.r]

Hi all, I would like to know what every one of you are using as a power unit for your mill, and if you can tell me your fuel consumption that would be a bonus. I'm running a Detroit 4-71 burning 2-3gph 

[Gearbox]

Rule of thumb 5 gallon of fuel a thousand feet per man per day . That 4 71 is an animal on a sawmill I have run one with a 3 71 and sawed 8000 feet in a 3 day weekend with a good crew of old men

[moodnacreek]

I am electric off a c series 175 kw gen. set. [Cummins]. I burn about the same as you or a bit more. Formally I sawed with a 318 Cat, 1949, around 90 hp. Ran all day on 10 gallons. Before that gas motors. They need to be 400 cu in. or more and have a good governor. Your 4-71 is a good unit for a sawmill. The price of diesel sure takes the fun out of it.

[Osterman.r]

Mood, you've got that right! Price of fuel sucks, I'm only 35 years old, but I never used to stress about buying fuel for anything. Dirt bikes, motor cycles, cars, trucks, heavy equipment. I think about it all the time now. 

[Guido Salvage]

In a prior life I had a 4-71 on an 01 Frick. I currently have a disassembled 00 that came with a Case LA gas engine. I suspect it is a fuel hog.

[Ron Wenrich]

We ran a 671, but we powered more than just the mill.  The mill was a portable Jackson Lumber Harvester.  It was an automatic mill that run by hydraulics.  The hydraulics also ran a log deck, turner, and blower.  We also ran a separate hydraulics unit that ran an edger.  We also had another 671 on a chipper.  I'm not sure of the fuel consumption, but we were running home heating oil (off road diesel).  Production on that mill was about 8 Mbf/day with a 5 man crew.  I remember running a 671 that was using about 10 gal/day.  Light production with a 2 man crew.

When we went to electric on a gen set, our fuel consumption was about 350 gal/wk, if I recall correctly.  But, that ran a whole lot more than just the mill.  Production was in the 50 Mbf/wk range with a 5 man crew.  There was additional fuel used in the loaders, skidders, and debarker. 

One way we were able to keep fuel prices down was to buy from a local fuel provider that could guarantee a price max.  If fuel prices slipped lower than the max, the lower price was posted.  They used the commodity markets to lock in prices.  Usually, that helped in the winter time price spikes. 

Are you going to a station to get your fuel or are you getting fuel delivered?  I noticed that the local gas station that sells off road diesel is higher than my fuel man.  A month ago, it was over $1/gal difference.

[Osterman.r]

Ron, I go to the local gas station and buy off-road. 30 gallons at a time. I only saw a few days a week, so I'm not burning a ton of fuel. But it sure cuts into the profit margins 

[Ron Wenrich]

I'd check to see what a delivery man would charge.  Put in a 275 gal tank and get it filled every other month or so.  You might save money in fuel, but you'll definitely save time and gas.

[moodnacreek]

To save money on fuel you have to invest in tanks. When someone goes off fuel oil and has a decent tank to remove, you bring that tank home and set it up with a little tin roof or something, Find out how much fuel you state will allow you to keep without registered tanks and try to have that much capacity. Find out who will sell you fuel for cash at the lowest price and when the price really drops, fill your tanks. $$$, pumps, responsibility, maintenance and additives. There is no easy way. You need to be in it in for the long run.  I have a connection for buying fuel I cannot reveal and I haul it at night.  Also have no real competition for rough circular rough cut so I get a good price for my wood. Non of this happened overnight. It is not easy to make all this happen.

[dgdrls]

I cannot speak from personal experience however, I thought you might find the information below useful,

Is your 471 Turbo-charged?

fuel consumption of turbocharged engines

Detroit Diesel 4-71 Naturally Aspirated Engine
The Detroit Diesel 4-71 engine shows a fuel consumption between 0.430 to 0.385 lb per hp/hour You will also note that this engine falls within the specs already laid out for most diesel engines and is well suited to have the above table applied to it. Thus: at continuous full power (1116 kW @ 2100 rpm) it will use approx 25.0 liters per hour.
Detroit 4-71 Naturally aspriated
Fuel Efficiency = 240 g/kW hour

Detroit Diesel 4-71T Turbo Engine
The fuel consumption for the 4-71T varies between .370 to .355 lb/hp hour. At full turbo boost the consumption in terms of lb/hp hour is also better. This averages approx 24% less fuel per kWh than the naturally aspirated engine.
So continuous full power (157 kW @ 2300 rpm) it will use approx 46.9 less 24% = 34 liters per hour.
Detroit 4-71 Turbo engine
Fuel Efficiency = 182 g/kW hour


D

[moodnacreek]

All 2 stroke Detroit's are super charged, very few are turbocharged. 

[jpassardi]

I have a 471 in my old 40K # excavator. Runs like a top. Unfortunately the 2 strokes aren't as efficient and the noise...well if you've been around one you know.

[barbender]

I couldn't believe the engine on the mill Gearbox was running was a Detroit...the exhaust pipe was 15'-20' tall and it was actually quiet!

[longtime lurker]

Perkins 1006T through a 2.5:1 Twin Disc.

Look I love 2 stroke Detroits. I've made a lot of money out of things powered by Detroit Diesel engines for many years. I admire them for their simplicity, reliability and cheap parts and forgive them the noise and the inevitable oil drips. I crawl up on one of my old skidders with the 4-53 and enjoy the day immensely. I hear some old KW go past with an 8v-71 and it makes me smile from ear to ear.

And it's 2023, and sawmilling is what I do for a living, and being lean mean and efficient is pretty much impossible with an engine that was designed before my father was born running all day

Problem with a 471 is if you're planning on replacing it when it dies beyond hope of repair you'll need to live to 207 years old. The things are about as indestructible as motors come. But they were built when fuel was cheap, and fuel is never going to be cheap again. It's just a matter of how long you need to hurt before you accept the inevitable.

[Osterman.r]

Lurker, we'll said... and I just bought a 671, it was cheap and a must have. So I guess I'll have to live to 414. I'd like to see some pictures of your Perkins setup.

[jpassardi]

LL: I couldn't agree more. You're spot on.
Hearing an ole screamin meanie will put a smile on your face.
Years ago there was a pickup at the drags with an 871 with a turbo and nitrous. You'd swear that 2 stroke was turning 12 grand.

[Resonator]

Years ago there was a pickup at the drags with an 871 with a turbo and nitrous. You'd swear that 2 stroke was turning 12 grand.

Sounds like a recipe for a "runaway". Quite a few videos out there showing what happens when a 2 stroke Detroit gets stuck running wide open, and then self destructs.

[Satamax]

Mood, you've got that right! Price of fuel sucks, I'm only 35 years old, but I never used to stress about buying fuel for anything. Dirt bikes, motor cycles, cars, trucks, heavy equipment. I think about it all the time now.

Well, there is a partial solution. 
What do you do with slabs? 
wood gas generator in diesel engine perkins 6-357 - YouTube
I really don't have the room to run mine on woodgas, but it is possible. 
I run  a 144kw volvo Genset. And from the start, i was looking into woodgas modification. 

[longtime lurker]

Woodgas is a different story. The old screaming demons are supposedly the easiest diesel engine to convert to gasification.

I've thought about it a few times and mostly wound up with questions that I can't find answers to around fuel (woodgas) quality with relation to varying species and moisture contents. And what I saw available as turnkey units were either too big or two small for my application. Diesel might be getting expensive but it's pretty easy to live with. Time is money too, and I don't want to waste it putting sticks on the fire so then you're up for a screw chipper and storage hopper and automatic feeders and all that stuff.

Stirling cycle engines on paper at least are the best waste fired power unit for a sawmill but information on those is even less available. 

If someone gets a Detroit based gasification unit effectively powering a sawmill I'd be all over that like the white on rice.

[barbender]

Detroits sound like they are spinning 12K when they are at 3000rpm.

[HPPDRoss]

I'm running a 3-71 on my #1 Meadows with a 48'' saw. It does really good for me and is pretty fuel efficient. I absolutely love the governor on it more than anything. No lag whatsoever.

[jpassardi]

Detroits sound like they are spinning 12K when they are at 3000rpm.

10-4, they're firing twice as often as a 4 stroke at the same RPM, 4K sounds like 8K.

[barbender]

Firing twice as much, then the sound pressure and high frequency whine of the Roots blower doubles that😂

[Tim]

Mood, you've got that right! Price of fuel sucks, I'm only 35 years old, but I never used to stress about buying fuel for anything. Dirt bikes, motor cycles, cars, trucks, heavy equipment. I think about it all the time now.

Well, there is a partial solution.
What do you do with slabs?
wood gas generator in diesel engine perkins 6-357 - YouTube
I really don't have the room to run mine on woodgas, but it is possible.
I run  a 144kw volvo Genset. And from the start, i was looking into woodgas modification.

I don't know if I would go the wood gas route with a diesel... I would try it with a gasoline powered engine in a heartbeat. However, I would process used vegetable oil to burn in my diesel.

At to the OP: I ran a Ford 300 6 cyl gas on our circular when we were sawing lumber... I had a Nissan Diesel on our edger and a 2.2l chev on the trimmers. We batched through what we were sawing so while all those engines could run at the same time if there was enough help around, they usually ran one at a time. We switched to shingles a little over 20 years ago and are currently running a Perkins 4.236 on the mill. It plays with it but, I really like Perkins. Easy on fuel, simple to fix and reliable except for not liking the cold.

My cousin a mile down the road is running a Cat L10 on his circular. It runs his whole line (head saw, hydraulic carriage, vertical edger, trimmers etc.)

My neighbour 2 miles in the other direction is running a couple 671 Detroits. One is on his debarker and the other on his sawmill (head saw, turner, hydraulic carriage, vertical edger, and trimmers) I can hear Ken two miles away and tell if he is sawing or debarking. The only way I can tell if Ken in the other direction is working is if I drive by. 

[Satamax]

Mood, you've got that right! Price of fuel sucks, I'm only 35 years old, but I never used to stress about buying fuel for anything. Dirt bikes, motor cycles, cars, trucks, heavy equipment. I think about it all the time now.

Well, there is a partial solution.
What do you do with slabs?
wood gas generator in diesel engine perkins 6-357 - YouTube
I really don't have the room to run mine on woodgas, but it is possible.
I run  a 144kw volvo Genset. And from the start, i was looking into woodgas modification.

I don't know if I would go the wood gas route with a diesel... I would try it with a gasoline powered engine in a heartbeat. However, I would process used vegetable oil to burn in my diesel.

The advantage of woodgas on a diesel, in a sawmill, is that you have plenty of fuel in form of slabs. Vegetable oil, either waste, or fresh, has to be scavenged or made. Mind you, it can also be used in conjunction with woodgas. I don't think woodgas can be used pure in a diesel.  You still need to have injection, to trigger the combustion. The injection acts as a spark plug more or less.
It's the same, pretty much, as propane injection in diesels.
If this make sense.

[handhewn]

I'm recently back to running my 60" circle saw powered by a  Detroit 6-71 two-stroke. Anybody out there know what my oil pressure should be at operating speed? It starts out at 30 lbs. and down to 20 lbs. after a few hours and stays there all day.

[moodnacreek]

Those screamin Jimmies are notorious for low oil pressure. If the oil pressure holds after warm up I would not worry. If the engine was shot it would keep going down. The 2 stroke heats to oil very fast and  very hot compared to many 4 strokes. Are you using 40 wt. ? That is what they call for unless cold season. When those engines are hot and dropped down to an idle there may be no pressure seen on the gage so don't idle too slow.

[handhewn]

I am not running 40 wt. I believe I'm running 15-40. I will change this before I run it again. Thanks much. I can't wait to see the difference. It seldom gets below 25 deg. here, is that cold?

[mudfarmer]

handhewn I don't remember what the book says but your oil pressure is the same as a healthy one I know intimately that runs about 8hrs a day most days of the year and has stayed the same apparently for at least a decade. moodnacreek as usual is right on the money including the bit about when you drop back to idle.

[handhewn]

Funny thing about low RPMs with my mill, I recently found out that if I screw up and drop my RPMs while running wood through the three blade edger, I will eat four v-belts at a total of $150. Now if I do drop my RPMs, I don't drop them much.

[dgdrls]

I am not running 40 wt. I believe I'm running 15-40. I will change this before I run it again. Thanks much. I can't wait to see the difference. It seldom gets below 25 deg. here, is that cold?

Handhewn,  look for straight 40wt with Sulphated Ash, %wt as far below 1.0 as you can find,

Delo 100 is a very good choice for 2 stroke DD Sulphated Ash, %wt is rated at 0.8.

D

[handhewn]

Thanks much dgdrls, I can't wait to try it. I would really like to see the oil pressure up where it was. 1939 and still running strong.

[moodnacreek]

1939?  I think that was the first year they where made. Does it have 3 air cleaners?