Image: Pictured at the last ‘Wheels Over Wanaka’ machinery show is this beautifully restored late-production IH 433 with Pay-Mate attachment, belonging to J.B. Richardson of Taumarunui. One class act. PHOTO: INTERNET
Based around a modular concept, the International Harvester model 433 PayScraper, launched in 1972, was an entirely new design, explains Richard Campbell.
The ‘System 400’ series of International PayScrapers consisted of four machines. A single-engined open bowl scraper, the 431 (which replaced the existing 270); a single-engined elevating scraper, the 442 (which replaced the E270); a twin-engined elevating scraper, the 444; and the subject of this article, the model 433, which was a twin-engined open bowl scraper.
The 444 and 433 were new to International’s range as the company had not offered twin-powered machines before. All machines shared a common tractor unit and a great deal of other componentry that allowed International Harvester to rationalise production and reduce its parts inventory considerably.
This modular concept for motor scrapers was also copied by Fiat-Allis who introduced its ‘200 series’ (260B, 261B, 262B and 263B) in 1974 – again, all sharing a common tractor unit and many other features. Imitation is the sincerest form of flattery!
International’s System 400 series expanded the company’s range of motor scrapers that, up until this time, was quite limited and rapidly becoming old technology.
International aimed squarely at the fattest segment of the motor scraper market – 14 to 20 cubic yards; an area long dominated by Terex and Caterpillar.
Traditional International owners were keen buyers of the new System 400 machines, but International Harvester had a bit of an uphill battle convincing buyers who were loyal to other brands, and sales of all the 400 series machines were moderate despite their efficiency, reliability, and good looks.
Unlike other manufacturers of the period, International did not offer any form of ride suspension on its motor scrapers which could have been one of the limiting factors in their acceptability.
Most popular of the new breed
The 433 was a twin-powered, 14-cubic-yard- capacity open bowl motor scraper that weighed around 34 tons empty and sold in greater numbers than all the rest of International’s System 400 machines.
International used two of its own diesel engines to power the 433, a model DVT800 turbocharged V8 diesel in the tractor unit that was rated at 310-flywheel horsepower, and a model DT466 six-cylinder turbocharged inline diesel rated at 185-flywheel horsepower in the scraper.
Both engines were already used in other International machines, which increased parts commonality between units. Twin-Disc supplied the matching five-speed powershift transmissions.
On a smooth haul road, the 433 was capable of 34 mph. Air-operated shoe type brakes were fitted to all four wheels.
Gooseneck, steering and bowl
The model 433 had a gooseneck similar in design to the Terex TS-18, but the steering system was decidedly Caterpillar in origin, having two ‘V’ shaped multiplier links connected to the steering cylinders that were mounted high up on the gooseneck.
The apron actuating system was also similar to Caterpillar’s, featuring inside mounted apron arms with a hydraulically actuated lever and link to raise and lower the apron.
Holding 14 cubic yards struck and 21 cubic yards heaped, the bowl was equipped with a four-section reversible and interchangeable cutting edge.
Two vertically mounted double-acting hydraulic cylinders attached directly from the top of the gooseneck to the bowl spreader bar provided lift and cutting-edge penetration (some 28 tons of down force).
Ejection was bulldozer style, powered by two double-acting hydraulic cylinders.
A bowl spillguard was fitted as standard equipment and helped prevent spillage of large chunks of earth falling over the back of the bowl onto the rear engine enclosure and fuel tank.
Compared to previous International Harvester scrapers, the System 400 series machines appeared quite angular, with most of the body panels being flat or squared off, a deliberate measure by IH that cut down the cost of manufacture considerably with very few compound curves to worry about.
Operator comforts
The 433 had very good visibility all round for operators, with the exhaust stack and air cleaner being set back to allow the operator a better, uninterrupted view to the right.
The instrument panel was set to the right of the steering column and contained all the necessary gauges. A smaller panel containing the rear engines gauges was set inside the rear left-hand side cowl of the scraper unit.
The 433 was normally delivered with a Bostrom air suspension seat and an open ROPS with a windshield. An open ROPS was standard from 1973 onwards.
A full ROPS air-conditioned cab was available as an option for colder climes.
Operating options
Internationals 433 could be supplied with an International Pay-Mate dual loading system.
This option allowed two 433s to load each other without the use of a separate push tractor (very similar to Caterpillar’s Push-Pull and Terex’s Twin-Hitch systems).
Pay-Mate was factory installed and could not be retrofitted to existing machines in the field, as a certain amount of reinforcement was required to the machines main frame. At the rear of the machine the scrapers push block, which contained the Pay-Mate hook, was extended and a substantial radiator guard for the rear engine was installed.
Improvements and cancellation
The International-Harvester 433 was well regarded by users and operators but did not sell in great quantities.
In 1977, an uprated 433B version was manufactured featuring an increase in horsepower in the tractor unit from 310 to 326-flywheel horsepower, plus a higher capacity hydraulic pump and a few exterior styling changes – noticeably the relocation of the front headlights from the bumper to the upper sides of the radiator surround.
Following the Dresser buy out of International Harvester’s Payline division in November 1982, all the remaining System 400 series machines were dropped from the product range.
For the model collector
Only one model of International’s 433 PayScraper has been produced. This was manufactured by First Gear to 1:25 scale.
The model is of exceptionally good quality, very accurate and fully functional.
It has also been issued in a couple of variations since its first release in 2004 – a limited run ‘mining white’ version, a gold-plated example, and also as a very rare, matched pair equipped with International’s Pay-Mate loading system.
Unfortunately, the model has not been available for several years, but is an impressive item worth adding to any 1:25 scale collection – if you can find one!