Unique sound of a direct drive working.

[Scrub Puller]

Yair . . .

I have been on the road awhile and chanced to happen on a few folks watching a stickshift D7 digging out a real large stump.

I parked up and joined them and listened in delight.

The operator knew what he was doing and was pushing the old girl pretty hard, she'd lug down and grunt and you could almost count the cylinders firing and then he'd throw the clutch . . . but never once he stalled it.

A couple of blokes were going on about how the thing was f****ed and the operator was killing it and an engine shouldn't bog down like that.

They had obviously never heard a DD working and I tried to explain the tractor was running fine, the engine coupled to the tracks with no converter but I don't think they were convinced.

Cheers.

 

[Zed]

 

[Zed]

G'day Scrub here's some pics of old Heidi the D7G we had at Casy Station, Antarctica. I was down there for a year in 2003/2004. Old direct drive had more levers than I ever saw before but it was a hoot to operate, we used it mostly for pulling sleds when building the Casey runway and also taking gear up to Law Dome which was 240km round trip. A couple of pics of her blizzed in, took a while to dig her out!!!

 

[lantraxco]

Those old engines were long stroke with a ton of flywheel, boatloads of torque and yes, they sounded like Thor's hammers when pulled down and working like an old plow horse, as you say you can almost count them firing. Stand close enough you can almost feel every pulse. The converter gives you some torque multiplication and when it stalls you have to give her more turns to make it go, higher rpm engine with less foot pounds, which is just the opposite of the system with direct drive.

Direct drive and a pony motor, steam locomotives, radial engine aircraft, Lord I was born in the wrong era....

 

[RonG]

You guys are teasing this old man but keep it up!!That D7 is only 4 cylinder so when you lug it down you can really hear those jugs popping.they were made to work in that low RPM range,they were cammed to be efficient any place they were as long as they were running.The only problem I ever had with a D7 was while boxing out a road in a new housing development our "mechanic" who was one of the brothers that inherited the business from their father and probably could not spell mechanic told me that the dozer was smoking too much while I was pushing and I should not be working the machine so hard but machine had a hole in the intake manifold so the engine was getting the fuel of a turbocharged engine but was only getting the intake pressure of a naturally aspirated engine so it was way overfueled and of course it was going to smoke.The brother "mechanic" in charge of the wrenches asked me once if I thought that that hole made the dozer smoke so it was obvious that he did not understand things too well.
I also got a reprimand from our mechanic "Arnold" at a different company I worked for because I was driving our lowbed with our Brockway tractor that had a 318 detroit and was gearing down for a railroad crossing and someone who was friends with Arnold thought that the the engine was turning too slow as I approached the tracks while looking to see if a train was coming but he was just jealous that that detroit could sound so good while that jake was slowing me down!!Ron G

 

[Scrub Puller]

Yair . . .

Good stuff fellers, you know where I am coming from, thanks for replies.

Its fascinating for me to see pictures like that! Thanks Zed.


Cheers.

 

[old-iron-habit]

And the three cylinder Cats are awsume sounding under load also. A unique sound for sure. I'll try to get a video of my 1939 Model 11 patrol under load this summer.

 

[oldirt]

about 45 years ago I watched a guy push dirt uphill to repair a large dam that had failed. he was running a D73T with a very worn out motor. It was about 95 degrees, I was above and behind him looking down with the sun low and at my back. he would push a load in low, pull down till you could count the pops, pull the clutch till the motor hit the governor then pop in the clutch and do it all over again. took him about three hits to get to the top.

another time when I was younger yet, I watched a guy push up broadbase terraces with a D814A. it never seemed to lug down much at all, and would usually burn the tracks in second against a full blade if he got careless and gouged. that tractor was owned by a guy who was absolutely meticulous in keeping that tractor in top shape and it really ran like it. it also had hyd boosted control levers for steering which looked kind of little to me at the time, he could run them with one hand over both levers. I was about 13 at the time.

 

[Scrub Puller]

Yair . . .

I love these discussions about old gear and how things used to be.

it also had hyd boosted control levers for steering which looked kind of little to me at the time,

So oldirt you are saying it had the Cat straight pull controls that worked back and forth in a console projecting from the dash rather than levers through the floor?

That straight pull actuation felt very strange to me after thousands of hours on the Allis's which just had a simple pivot.

Cheers.

 

[Welder Dave]

When they improved the road to my land, they used a direct drive D8H with a cable scraper to haul out the clay. The operator let the clutch out and hit the throttle at the same time and it lugged right down, poured out the black smoke but never stalled despite the low RPM when the clutch was let out. I think the County still has the 2 D8H's purchased new in about 68 with the CCU's and cable scrapers. The one used on my road had new undercarriage and although it needed some work on the pup motor, ran great. They thought about trading them in but Finning was only going to give them about $10,000 a piece for them. They figured they were more useful to keep.

 

[RonG]

Here is a pic of the old D7 that smoked,I should have included it in my post but I didn't have a pic of the old long nose Brockway.I took the pic from an EC200 Ackerman that I was loading trucks with at the time.Ron GView attachment MVC-005F.JPG

 

[Scrub Puller]

Yair . . .

The operator let the clutch out

Nope. I'm just be'in smart azz picky Welder Dave but he would have actually pulled the clutch in.( big grin) I hear and can see what you are saying though, those old girls can pour out the coal.

Cheers.

 

[ol'stonebreaker]

I spent a lot of time on D-8 14A's and 36A's feeding crusher. Most times w/ the 36A being turbo'd if you saw smoke coming out the stack it was time to either lose part of the load or grab a gear. The 14A not so much. How many stick cat skinners know how the Johnson bar got it's name?
Mike

 

[RonG]

If I would just shut up I would read the answer and pretend that I knew all along but noone happened to say it within earshot that I could hear since 1960 and I have heard the reversing lever called that since I started back then so let me hear it,it's my turn.Ron G

 

[TomA]

I stopped to watch a local guys powershift D7G working once, kind of disappointing, all I could hear was planetaries singing.

 

[ol'stonebreaker]

RonG, The Johnson bar was the name of the reversing lever in a steam locomotive. How it got a sexual connotation attached to it is a mystery to me.
Mike

 

[RonG]

Now we all know....lol.I think I have heard that before but I will forget it again for sure at my age!!Thanks Mike.Ron G

 

[Birken Vogt]

YThe operator knew what he was doing and was pushing the old girl pretty hard, she'd lug down and grunt and you could almost count the cylinders firing and then he'd throw the clutch . . . but never once he stalled it.

They had obviously never heard a DD working and I tried to explain the tractor was running fine, the engine coupled to the tracks with no converter but I don't think they were convinced.

My Dad tells a story about how he went out in the woods to pick up his Dad who was running an old D9 in the 1970s sometime. He was ripping rock deep with a single shank and he said Grandpa had it working just above idle at the point when the tracks were just about to slip, he knew exactly where that point of maximum production was. When he pulled that ripper out of the ground (it had gotten dark already) the tip was glowing a dull red.

 

[lantraxco]

Johnson bar goes back to the days of steam locomotives dunnit?

 

[Scrub Puller]

Yair . . .

I had never heard of a "Johnson Bar" with regard to tractors until I saw it on this forum . . . somehow I have always associated it with steam locomotives and (I think) the control used to reverse the rotation of certain large marine engines.

We always just knew it as the forward/reverse lever.

Cheers.