Some more queries on basic gearing VS engine RPM

A lot of people forget what things were once like, still run my 320 on doubles at times, even empty with double deck crates it's 70 km/h on the Hay plains
I have crossed the Hay plains numerous times pulling doubles with general types of freight at full weight or more and struggle to get 60 km/h

The first Peterbuilts were geared for around 50 MPH, dunno about them KW's but I would guess about the same

The amount of stories I have read on Faceless book were people claim they sat on 120 km/h in a Dodge with a 653 screamer are just that stories

Or even the infamous Grey Ghost yarns and alledged speeds and so on, these old jiggers would of reving to over 3000

I was talking to a well known truck restorer one day about this and he just advised me to let them keep on talking :whistle:

So I guess a lot of yarns are just that

Even when people want to gear trucks up now for running to shows it becomes very apparent just how gutless they are and any sort of a rise or wind and they struggle to hold top gear
So this gearing is pretty important, and the science behind it is pretty spot on

Remember the old Cummins adds of the late 70's early 80's and they had the "Formula" range of motors
They used I gather a spread sheet and depending on the height, weight, speed and so on they came up with a answer on the best motor and gearing for the job

IH had a similar program

Mack just recon that the dog was tough and further explanation wasnt needed

Dont recall GM having anything for their sales people except the "Fuel Pincher" series that covered all including the little 4 stroke that never really made it

Cat was like Mack, they new their motors were tough as nails and I dont recall any program type thing for them

Sorry get a tad off topic


Paul

NO, don't think we have wandered all that far from original topic.
Lot of sense in what you're saying, Mrs. How easy we forget "how it used to be".
I liked your reference to the "pub talk", go into any waterhole where they (truckies) hang out (and the diesel fumes knock the head off the beer) and I'll bet you quids that by the end of the night the trucks have gotten faster, the loads heavier, the times between desinations are being compared to a Boeing 747!

We can all probably slag off at this sort of talk, but it does keep the forum ticking over, and as you say, we don't take it all as gospel. Maybe a lot of it should be filed under the "Need a few good yarns!" banner?

What I like is that it is an open forum, the banter back and forth. You know damn well that if you make an outrageous statement, or even embellish the truth a bit, someone will come along and put you in your place!
I have no problem whatsoever with this myself, if I'm wrong, I'm wrong, get over it and move along.
Been on this forum around 7 years I think now, can't say I have really seen any gross disrespect, sure there's been open opposition to some topics. Reckon the moderators are really on top of this, do a great (unpaid as far as I know) job and keep a firm hold of things. The odd topic that looks like it may get out of hand, soon gets reined in.
Howzat for wandering off topic! The older I get, the more senility creeps in!

So, back to Mrs, response, yes, days of 160 or 180 Crummins, 6V53's etc etc are like button up boots and fidelity, gone!
Fer cryin out loud! The days of when a lot of members on here started out, they wouldn't be using what was available for motive power, HP, as a PILOT motor these days! You guys DO remember pilot motors, don't you? Donkey engines? Little engines used to start bigger engines? No? Don't matter.
Last drivers re-union I went to , not all that long ago either, bloke said he was waiting for his new truck to arrive. "what did you buy?" he was asked, "how many horses?"
"Oh, had it de-tuned from 700 back to 650, try and get a bit of economy outta it!"
Suppose that's about the norm these days.

Now, I know this is a little off topic, but when I was a hairy cheeked young know-it-all back in the early sixties, worked for a mob in Camden NSW who had quite a bit of earthmoving gear.
Bought a reasonably late "B" model Mack for the heavier stuff they carted, (biggest was a new D8H at the time) and completely refurbished it from the ground up. Big bit of gear at the time, either a "P" motor or 711, long time ago. They also had an Inter there, had a 6 cylinder petrol engine, they also pulled off the road once the Mack was going.
Either a R190 or an R200, bogie drive. , they put a Cat 6 cylinder in it (same engine that was in a Cat 12 grader at the time), so what would that be ? 160HP?? Had what I thought was an unusual main transmission, the one that had the TWO reverses in the main box, and also had a 3 speed under-direct-over auxilliary. Decompression lever came through the firewall just about level with the passengers right knee.
Don't remember what happened with either the company or all the gear they had, suspect a lot of it ended up down the South Coast at a cousins depot, who was big down there as well.
I remember at the time the float driver telling me that the Inter wasn't a bad truck with the petrol engine, but it was an entirely new deal with the Cat "grader motor". Not as good as the Mack, mind you, but still a handy bit of gear.
The B model had the air starter, the Cat powered inter sounded very similar winding over on decompression.

Speaking of engine transplants, we had to go out to the sand pits on the Nepean River one time, pick up some boom extensions off an old Osgood dragline that had been decommissioned. Fitters already had the main boom on the ground. Were getting the engine ready to lift out, half the shed already removed. Being a sticky beak, wandered over and here's this ancient Cat 6 cylinder engine, don't know what size, but looked about the same as a D8 engine.
Had the original pilot (or donkey) motor set up, and I remembered hearing it when still working, from the other side of the river.
You could hear that old six cylinder (no turbo!) just dig into her reserves when dragging a bucketful of wet clinging sand out of the sand beds and stockpiling. We were still dicking around at lunch time and asked one of the fitters if the Cat engine was an original.
No, he said, came out with a huge old petrol engine, didn't say what make, maybe a Continental? anyway. the sheer cost of running this thing on petrol was getting prohibitive. They got hold of this old 5 cylinder Ruston engine from somewhere or other, tried it, too asthmatic and underpowered anyway. The original owners had bought this Osgood along with the dozer at some dispersal sale, maybe Govt auctions, a handful of trucks (probably also ex wartime) and set it up as a family business. The old man carked it and the sons were left to run the business and as usual, all wanted to run the show, no one wanted to do the actual work. Went downhill from there, think that the repo's moved in, everything carved up for little more than scrap value to pay a few creditors, we were after the boom sections only.
When asked what they were going to do with the Cat engine, one of the fitters said to me, "Wanta buy it? Good old motor, goes like a clock, probably be lucky to get a hundred bucks for it (this just about the time of decimal changeover.)"
" A hunderd bucks ? Fifty Quid? That's 5 weeks wages for me!" Only getting a fiver a week ($10) plus doing a couple of hours O/T during the week and another 8 hours on Saturday, you could double that. Besides, what was I gonna do with it ? Repowerer my 1953 Hillman?
I think the only ones who did any good out of the whole setup were the two fitters, a lot of old bits and pieces that could be carried by hand seem to have mysteriously "walked" out the back gate, they often seemed to be there well after dark!
As usual I digress, wander off course, but, there you have it. Cheers, Dave

For Dave and Mrsmackpaul.
Agree most trucks were geared for the job in hand. Cover a lot of ground at 50 mph if you put in the time at the wheel.
Tyres and roads not as advanced, so less trouble and no stress about speeding tickets.

There were fast trucks, whether specced that way or modified. Spent some nights on weekend leave on the Hume,
Casula to Melbourne and back, 1970. Had a 57 Mainline ute and drove between 60 and 80 mph where possible.
Followed Grey Ghosts uphill through curves and hard to stay with them, they knew where to hit each corner just right.
On the few straight sections, well above 80 mph. Good to follow, no sense to overtake. Lighter loads, tall diffs.

Know of an old Leyland horse float, 680 motor, overdrive box and joey box. Suicide machine at 80 plus mph.
Mate pulled up in his T Line, 8-92 GM tuned up. Accused of doing 138 k's, asked if they had a lower reading.
Told that was the lowest of 3 readings!
Mid to late 1970 KW SAR and Cabovers could be specced with 93 mph. diffs, whatever they were.
Fuel was cheap then.

Army plant course, Cat 12 Grader 115 HP from memory. Good torque, suited for purpose. Sounds like it went
well in the truck too Dave. Some of the guys knew how to make unauthorised adjustments to them too.
Same capacity motor in the 966 loaders, turboed, were 150 HP.

That surprised me, the 6 cyl N/A Cat 12 engine only putting out 115 hp or in the case of the 66, 150 hp. At first glance you would think that it would make the Inter a bit anaemic, but were a very torquey engine and geared down pretty well. Even with a P motor, the B model would be knocking out around the 180, I'd be thinking and it had the quad box. So the 190 (or/200) with the 5x3 did a great job for its size. Neither were very quick on the road, but didn't have to be. That Inter moved one of Chtisties D9G's with the bull blade and rippers on it with must have been among the first of Drakes swing wing floats . Good load for that small engine.

Paul FH
Your memories pretty good.
Just looking up some figures for the direct start D333 engine (even though it retained the decompression lever), in the Cat 12 E which was the first use of that particular engine in a grader.
Your right, the DE-RATED H.P. quoted is indeed 115 HP, same engine opened up to 125 HP on the 12F series, last model before articulation, but did away with the old "knuckle-busting" controls and went to a more user friendly "power assist" controls.
I knew that they got around in a few different guises, D6, lighting plants, irrigation pumps etc etc, saw one listed as ex-military spec gen set rated 200HP at 2100RPM.
Later morphed into the 3306 engine.
So, just maybe they had it rated a bit higher than the standard Cat 12 engine, would need a bit more RPM range as well, driving a 5X3 transmission. So maybe the WAG around the 160HP may not have been that far out.
Dave_64

Yes Dave, adjustments were made to improve output.
Cat opted for reliability with their plant - good name hard to establish,
easy to lose. Some blokes can break anything mechanical.
The Cat 12 grader motors were set to match load requirements. The two gear
boxes provided the right ratio for the load. Some of our blokes knew how to
give them more RPM and more fuel, which increased output and road speed.
Of course, reliability reduces. Not a problem when the army owned the units!

Later had some experience with Cat 3208 V8 power. Some set at 170 HP to
meet emissions back in 1970's. Motor could be equipped and set at up to
350 HP with reduced reliability. Probably ideal at 250 HP turboed in a
local or country delivery truck. Much better motors available now, but again
some blokes can break anything. Very challenging for manufacturers.

Back in the '70s and '80s, the 32 and 40 foot NSW Police launches were powered by twin 350 and 454 Chevs. They each carried 200 gallons of petrol and some had a speed of up to 30mph and a range of about 10 hours, if pushed hard.

After one boat exploded at the wharf after being fueled, out came the Chevs and in went 210hp 3208 Cats. Speed dropped to about 20 mph but range went to around 24 hours. Ruined a good thing for the crews.

Pretty sure Cat motors are rated at 100% power for 100% duty cycle

The old D7 B of mine is 95 hp yet my 120 hp IH 4WD wheeled jobby struggles to pull it with zero load and the blade up

The Cat hp is different than normal hp in a GM or Cummins.
Mack hp Im told is measured at the rear wheels, dunno if this is true or not but Im told this explains how a 320 Mack can out pull a 400 Cummins or 8V92 GM

Dunno if any of that last bit is true or not, Swishman should know as Im pretty sure he has a 892 and a 320 Mack

Paul

Paul and Paul

I think this is why the ONLY measure of true horsepower on any vehicle is that delivered at the wheels ie on a dyno.

Every vehicle has different losses from the fan to the pressure in the tyres and even identical vehicles of the same model will produce different figues on a dyno.

Suzuki outboard motors gained a reputation of having much more power than their Johnson, Yamaha etc rivals because all the others rated their motors at the crankshaft while Suzuki rated theirs at the prop.

Aircraft engines have maximum power rpm figures for limited time (usually 5 minutes) while the maximum continuous is far less than that figure.

Many cars have maximum horsepower 4.500 to 6.000 rpm. How long would they last at that speed continuous?

I am sure you a right in thinking Caterpillar sucked up the criticism of lesser power by allowing their engines to only max out at a safe continuous speed and gained great reliability reputation. GM and Cummins blew them out of the water with max power but if the operators ran at that continuously they were in the shop long before the Cats.

The Poms did not even try to compete and had giant engines producing the power of a well tuned lawnmower but being handed down from father to son for 6 generations before anyone even looked at them.

Lang

Mrs
gudday m8
RE: Swishman should know as Im pretty sure he has a 892 and a 320 Mack
The detroit GM 2 stroke diesels perform like a 2 stroke Motor bike or lawn mower
They all luv revs
Yes 4 best result Drive m as tho U stole it
I think U do more damge to the 2 strokes if U only drive m on the max torque Detroit say .. 1500rpm ( they casn slurry up)
but let m screem out to the govonor @ 2100rpm now U get n sumwhere (even flight revs of 2500 they luv it n do perform
comparing our KW SAR with 8-92t @ 1200 ft Lb it perform well
but the coolpower Mack @ 1000 ft lb u got to think not much difference to the 8v-92t
most 4 strokers R a luggn motor where the 2 strokers perform best with max revs
cya