Cat J621 motor scraper

[biggerdigger]

For all of you who like our articles on classic motor scrapers, the latest is on the Cat J621. You'll find it here: http://www.contrafedpublishing.co.nz/Historical/Classic+Motorscrapers/Elevating+The+Caterpillar+J621.html

[BIG D]

I forgot all about this particular engine it was 4 valves per cyclinder and dual over head cams and valves were paralell ported and yes we called them clatterpillar like mentioned the same engine used in over the road trucking named 1676 a very hard engine to work on and a lot of parts for what it ocompilished yes one of the ghosts in Cats secret closet thanks the BIG D

[Phil]

I operated a 621A for a season, the engine was unnerving at times to sit beside. It was a real powerhouse, 300 hp was pretty modest I think, and coupled with that transmission, it really flew. Unexplained failures were common, too high a bearing load I was told. The engine had to have been one of the first to use spacer plates. I was told it was a more powerful machine than it's predecessor the famous 621B. A Cat shop foreman in charge of the rebuilding facility told me once that engine was why he got grey hairs. Phil

[DPete]

We had one where I worked back in the 70's. All I remember is that thing beating the daylights outa me. No cushion hitch and a poor excuse for a seat suspension.

[Deas Plant]

Hi, Folks.
That same engine that was in the 621A's also powered the original Cat 980A 4wd loaders and was a real powerhouse. I personally never had any problems with it but the 980A that I operated was comparatively new. It was a little noisy as I remember but I was a little younger then too and it didn't bother me all that much - - - - - then.

[Phil]

I understand Cat made a kit to put the 621B engine(3406) in the 621A. It involved quite a few changes I was told. A used crankshaft was almost impossible to find. Used engine blocks for sale were rare too. Cat sure made up for it with the 621 design, it was a beautiful machine. Phil

[Deas Plant]

Hi, Phil.
As I understand it, the original J621 scraper was a 'cobbled-together' effort. I understood that Cat built the prime movers and Johnson - whoever they were - built, or at least designed, the scrapers. I was always told that the 'J' in the name stood for 'Johnson'.

[Buckethead]

The J621 replaced the J619. The J621 was renumbered 623.

[Deas Plant]

Hi, Buckethead.
My ol' mem'ry may be failing me but I can't recall ever seeing a J619 DownUnder, only 619's. I even got to run one uv 'em - briefly - then back on my D8H pushcat.

[WabcoMan]

The J619 was not built in any great numbers.
As Des stated it was cobbled together - Cat prime mover & Johnson bowl.
The J621 was the same deal.
Cat had to get into the elevator market as IH, Allis-Chalmers, Michigan & Wabco were already well established there and taking sales away.

Caterpillar bought Johnson outright to secure the elevating scraper technology & save themselves heaps of $$'s in R&D costs (they couldn't buy Hancock because Clark got in first !).

The 623 was the J621's replacement with a few refinements over the J621.
It too was not built in any great quantity.
However, it's replacement, the 623B was a huge success for Caterpillar and also a great machine to operate.

The 613A was designed and built by Johnson who were going to market it themselves up against the Wabco 111A & Euclid S-12E but Cat bought them out before they could market it.
If you have a look at the serial number plates of the early 613's you will see "built by Johnson Manufacturing" on the plate (both tractor & scraper).:Pointhead

[Phil]

That's very interesting Wabcoman, especially the note about R&D costs. I have seen the elevating 621 go at auction years ago. A mechanic for a construction company once held up a connecting rod for a 621A and one from a DW21 (D337F). Quite a huge difference in the bearing surface area, he noted, even after you take into account that there are 8 of one and 6 of the other. Horsepower was similar between the 2 engines he felt.

Speaking of Wabco's my father had the Letournou C-pulls years ago, ironically 2 identical machines are not far from here and can't be bought. They continue to sit and rust and I fear the bulging field laminations have rusted to much now and ruined the windings. Phil:)

[Stick Pro]

I have a 613A and a 613B and they bolth have the manufactured by johnson tags on them they bolth are a good machine we run the every day

[Phil]

I remember seeing a 613B once. What years were they made? Scrapers have wrecked my back, I have to be careful now whatever I'm doing, no more heavy lifting. I miss the smell of the diesel smoke. Phil

[alan627b]

J621 and early 623's pics taken about 19778-1980. Pardon quality, originally taken with a 126 Instamatic....

[ronnie]

Hi, Buckethead.
My ol' mem'ry may be failing me but I can't recall ever seeing a J619 DownUnder, only 619's. I even got to run one uv 'em - briefly - then back on my D8H pushcat.

lucky you i'm still somewhat of a young man i think at 40 but i've had the privelage(back breaking,punishment) of sittin in the seat of this moving pile of scrap iron( nice way of sayin junk) everyman who has ever had to endure that punishment should've been jacked up and a c model 31 put under him thank God for coushin hitche's and 8 speed tranny's

[Deas Plant]

Hi, Ronnie.
Lucky me????????????? Nah!!!!!!!!!!!!!!! Smart me. I figured out VERY early in my association with them that there wuz only two ways to look at scrapers if I HAD to work with them, from the seat of a grader maintaining the hauls roads or over the blade of a push-cat. ALL of my ventures into the 'pilot houses' of scrapers have been of my choosing and of BRIEF duration.

[WabcoMan]

Gee Des, where's your sense of adventure !!

I spent 13 years at the controls of various motor scrapers.
Now that I'm "indoors" I still never pass up an opportunity to do a few turns when the opportunity arises:)

[ronnie]

i'm a workin forman now all i really have to operate is my d-39 komatsu but i have 2 friends that are scraper hands where i work and i enjoy swapin out at times i don't like our scrapers to me a scraper is no good without a back motor we only got 4 but we don't do huge job's the 21's we have are like babies i myself like the 37's never been on a new scraper this 1 lever does all i don't think i'd like that

[Deas Plant]

Hi, WabcoMan.
Read Ronnie's post above mine, then read this:


"MY back is still good."

'Nuff said?

[WabcoMan]

Hi Deas,

I agree that some of those beasties will give you a bad ride.
However I've been fortunate enough to sample a lot of machines and know which ones to steer clear of.
Also, I resisted the urge to go "cowboy" and concentrated on doing a good job.
My backs still in good condition 56 years on

Hard Riding Scrapers:
Cat 613
Cat 619
Cat J621
Cat DW-21
Cat 627 (non-cushion hitch)
Euclid TS-14 (if operated too fast)
Terex TS-18 (made me feel seasick !)
Euclid S-18
Terex S-11E

Good riding scrapers:
Any Cat 3-axle unit, especially DW20's
Cat 637
Euclid SS-12
Euclid TS-24
LeTourneau Westinghouse C
Wabco 111A
Michigan 110HT
Wabco 222
Wabco 333FT
Wabco 252FT

There are others which I've forgotten but that'll do for a short list

[Someguy]

Hi Deas,

I agree that some of those beasties will give you a bad ride.
However I've been fortunate enough to sample a lot of machines and know which ones to steer clear of.
Also, I resisted the urge to go "cowboy" and concentrated on doing a good job.
My backs still in good condition 56 years on

Hard Riding Scrapers:
Cat 613
Cat 619
Cat J621
Cat DW-21
Cat 627 (non-cushion hitch)
Euclid TS-14 (if operated too fast)
Terex TS-18 (made me feel seasick !)
Euclid S-18
Terex S-11E

Good riding scrapers:
Any Cat 3-axle unit, especially DW20's
Cat 637
Euclid SS-12
Euclid TS-24
LeTourneau Westinghouse C
Wabco 111A
Michigan 110HT
Wabco 222
Wabco 333FT
Wabco 252FT

There are others which I've forgotten but that'll do for a short list

Which of those scrapers had suspension ? So the 2 axle tractors ride better than the single axle buggies that are so common these days ?

[alan627b]

Cat started putting cushion hitches on the 600 series in the late 60's, and the were pretty much standard by the mid 70's.
615 had a suspended axle, maybe the latest 613.
Terex has the suspended axle on the Loadrunner TS24B's, I am not sure about other models. Maybe the TS14 C and newer?
Komatsu scrapers from the late 80's had a suspended axle too. Suspended axles being a nitrogen gas/hydraulic strut sort of setup, similar to the how the cushion hitch works on a Cat.
Some later John Deere scrapers have the suspended axle as well.
The 3 axle scrapers ride better than a 2 axle with no cushion ride, some of the other guys will have to tell you exactly how much better. I haven't been fortunate (?) enough to run a 3 axle....yet.
Allis Chalmers and International scrapers are stiff knecks. And that's what they'll give you, too!
alan627b

[WabcoMan]

Which of those scrapers had suspension ? So the 2 axle tractors ride better than the single axle buggies that are so common these days ?

The 637 had cushion hitch - and believe me it needed it.
You soon remeber to engage it if you'd forgotten !

I've operated several types of TS-24 and they all rode pretty good.
The 24B 'Loadrunner' was an excellent ride.
It had the suspended axle.

3-axle scrapers by their very design are easier riding but take a bit more room to turn round in.
They're not much use in hilly country however.