The Euclid C-6/Terex 82-30 revisited

This month we will have a re-look at a very iconic bulldozer, the Euclid C-6/82-30, a machine intended to take on Caterpillar, International-Harvester and Allis-Chalmers at their own game.  By Richard Campbell.

The Euclid C-6 was introduced by General Motors Euclid Division in 1959 after an extensive period of field testing.

It got its name from the fact that it was basically half of Euclid’s previously introduced model TC-12 twin-dozer, the C-6 (half of a TC-12), was classified as a D7-sized track type tractor, and was rather unique in appearance with its radiator mounted in the back.

The radiator location proved practical, especially when the machine was used in the bush or for logging where it was out of harm’s way, and reduced the buildup of trash and leaves that often plagued machines with conventional front-mounted radiators. The radiator cooling fan was V-belt driven by an extension shaft from the engine.

The General Motors’ research and development team did a great deal of study before finally settling on the final layout of the C-6, and deliberately kept the nose free for the mounting of equipment while maintaining a narrow profile for better forward visibility.

As such, the C-6 did not resemble any other track type tractors of the period, which did not detract from the machine’s performance, and the C-6 went on to establish a good reputation for its strength and reliability.

When initially offered for sale, the standard engine was a GM (of course) model 6-71, inline, 6-cylinder naturally aspirated diesel with a 218 flywheel horsepower output.

Within a year of the C-6’s introduction, the horsepower had been raised to 227 flywheel horsepower.

Alternatively, and at customer request, a Cummins NH220 engine could be installed at the factory as an ‘standard’ option.

However, most users opted for the GM powerplant, as it was in widespread use both in earthmoving as well as forestry, and spare parts as well as capable service people were plentiful. The Cummins engine option was subsequently dropped after two years due to low demand.

Keeping it in the family, GM’s Allison division supplied the transmission for the C-6. This was a full powershift transmission with three forward and three reverse speeds.

Planetary final drives were standard right from the start, Euclid being one of the very first manufacturers to offer this mode of power train in a track type tractor. The C-6 was usually supplied as standard on 20-inch single grouser track shoes. Euclid did ensure however, that there were many other optional sizes that could be fitted depending on the end user’s requirements.

Access to the operator’s area was easy and the operator’s compartment had a wide flat deck that provided plenty of legroom.

The air cleaner, originally located on the left front fender, was relocated at an early stage in the machine’s production life to provide better access and forward visibility for the operator.

Right from the outset, the C-6 was very ‘ergonomically’ designed with all the operating levers and other controls mounted close to the operator and requiring minimal physical effort to operate.

Although the number and position of some of the controls changed as the machine was developed, there were never any odd levers projecting through the floor plate other than the master brake pedal and decelerator, making for an exceptionally clutter free layout and one that was easy to keep clean.

Visibility on earlier machines equipped with the Garwood cable blade arrangement was very good. However, with the advent of reliable hydraulics, machines fitted with the new single cylinder hydraulic blade lift ram did suffer from restricted forward visibility, especially when push loading scrapers, and I speak from experience!

Machine iterations

During its production life, the C-6 underwent many upgrades plus a few changes in designation including a major re-branding from Euclid to Terex in 1968 plus a designation change from C-6 to 82-30.

The Euclid/Terex C-6/82-30 also underwent several model phases during its production life that changed the machines appearance only marginally as most of the improvements were internal.

The build phases can be categorized as follows: C-6-2 (first production model introduced in 1959), C-6-3, C-6-4, C-6-5, 82-30EA, 82-30FA & 82-30FAT, a turbocharged version.

There was also a Terex 82-30B version introduced in 1973, but this model is so different it falls outside the scope of this article.

The C-6/82-30 was also manufactured in the UK at Euclid’s plant in Newhouse, Scotland, and several hundred were built there before its dozer production line finally closed down in the late 1970s.

Work tools

Initially, the manufacture of bulldozer blades for the C-6/82-30 was undertaken by Garwood Industries, a long established manufacturer of these type of attachments.

Attachments produced by Garwood included straight, angle and ‘U’ blades, pusher plates, single and double drum cable controls, and radial and parallelogram rippers.

However, Garwood was purchased by Allis-Chalmers in the mid-1960s and, not wanting any competition from one of their rivals, put an end to the manufacturing agreement.

Euclid were then forced to build its own dozer blades and turned to Ateco and CRC-Kelley for rippers, and to Hyster and Carco for logging winches.

The C-6 in New Zealand

Size-wise, the C-6/82-30 sat in between the Caterpillar D7 and D8 and was also a competitor to the International TD-20 and Allis-Chalmers HD16.

New Zealand franchise holder for Euclid when the C-6 was first introduced was Clyde Engineering with its head office in Wellington.

Clyde imported over 45 Euclid C6s and 82-30s prior to the introduction of its replacement, the model 82-30B.

These machines were used New Zealand wide in all facets of construction from general earthworks to logging.

Several well-known Kiwi companies owned Euclid C-6s, including Feast Contractors, Fletcher Construction, the Ministry of Works (who had a rare Cummins powered example), Fenton Brothers, H Allen Mills, JC Anderson, Forest Products, and Taylor and Culley.

Due to their extremely rugged construction, wide commonality of parts and a good local knowledge of GM service protocols, Euclid/Terex C-6’s were very hard to kill – and many of them served out long and productive lives with new owners after their original purchasers had traded them in on newer machines.

Some machines even found a new vocation as gravity scrub rolling tractors, the type being quite popular in this role due to its very low center of gravity.

For the model collector

Regrettably, due to several reasons, models of the Euclid C-6/Terex 82-30 are not generally available outside of specialist resin models.

EMD Models do, however, produce three resin-cast versions of the C-6 including an example fitted with a cab and ripper, but these command some serious money.

All have the hydraulic blade. It is to be hoped that in the future, models of this iconic 60s-era dozer will become more widely available (and at a cheaper price!).

Brief Specifications Euclid C-6-5 (the most numerous production model)

Engine:                        General Motors 6-71 inline 6-cylinder naturally aspirated diesel rated at 227 horsepower.

Transmission:             Allison TT2200 series, 3-speed full powershift with integral torque converter.

Steering:                      Hydraulically actuated clutches & brakes.

Undercarriage:           7-roller track frame with pinned pivot shaft.

Gauge:                        78”.

Std.Track Shoe:          20”.

Operating Weight:      21½ tons with blade and ripper.


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