1st production CMP 6x6

[ramtank2]

When was 1st CMP 6x6 produced?

[Keith Webb]

I'm sure David Hayward will be able to give the precise dates... I think the prototype (which I've not seen any photographs of) was a cab 12 which dates it to late 1941; I think production commenced in 1942.

David?

[David_Hayward (RIP)]

On 16 October 1940 a meeting was held between Major Franklin, H.J. Stevenson, E.F. Armstrong [of GM of Canada], and A.A. Maynard. The meeting agreed the specifications for a new design of truck to be ordered from GM of Canada, with a 160-inch wheelbase to the centreline of the bogie, with new heavier Ford steering ends and D.A. Shock absorbers, plus two rear axles with one offset from the other on the centre though rear hubs and bearings to be as per existing 4 x 4 though with two propeller shaft drive and Timken type bogie. The engine was to be a ‘GMC 370 cu. in. with suitable Clutch; Largest Fan with suitable belt’, although it was in fact a 270 cu. in. unit. The transmission was to be a Clark 202V or 185F with tyre pump. The transfer case was to be standard type without P.T.O., though the P.T.O. was to be a split propeller shaft type and the transfer case had to be in neutral when using take-off. The sheet metal was to be altered to suit the larger engine and transmission.

In the meantime, E.L. Simpson of the Automotive Engineering Department at Ford of Canada wrote to Brigadier N.O. Carr as he was by then, the Deputy-MGO on 19 October 1940 and sent copies of composite chassis drawings showing the installation of the Lincoln Zephyr V-12 [1940-41 120 b.h.p.] engine in the ‘six-wheeler’ which presumably referred to the F.60H, and also sent power curves of the Zephyr engine and then engine then being used in military vehicles, which was the standard Ford V-8 and not the larger Mercury V-8. The Zephyr engine was available in quantity and Ford proposed converting for test purposes one of the DND vehicles then at their plant: would Carr give permission for the conversion please? The vehicles could be converted to 6 x 6 configuration ‘at your convenience’ [hint, hint!]. The advantage that the 290 cu. in. U.S. V-12 had was that it was produced in right-hand drive form.

On 26 November 1940 N.C. Millman [formerly of GM of Canada] but by then of the Directorate of Ordnance Services (Mech.) in Ottawa, wrote to GM of Canada and asked for a quote to build a 6 x 6 chassis. J.A. Lane, the Export Manager who handled such matters replied on 30 December that the chassis that ‘we are developing’ would cost an estimated $15,000. This seems to confirm that the special chassis was already underway.

The Director of Mechanical Maintenance, Francis Farwell, wrote in December 1941 that on 15 December 1940 ten DND officers went to Kingston, Ontario to road test a 6 x 4 chassis then used as an Army Field Workshop with standard GS body. At the conclusion of that visit Farwell took the position that the chassis was not satisfactory for gross loads in excess of 18,000 lbs. They then asked the Design Branch to provide a heavier chassis with larger engine that would be satisfactory fro gross load sup to 25,000 lbs. That then led to discussions concerning a heavier Dodge chassis with bigger engine, and then International Harvester, Dodge and White regarding vehicles with greater horsepower and capacity for loads from 20,000 to 25,000 lbs. Gross. However, a Mr. Stevenson wrote 13 January 1941 prior to the discussions recommending that the 6 x 4 chassis be retained with certain changes and on 22 January wrote asking that tyres be changed from 10.50 x 20 to 10.50 x 16 to improve the 6 x 4 performance. However, it was apparent by spring 1941 that the 6 x 4 [Ford F.60H] was unsatisfactory: London wrote 24 May 1941 that further trials on the lorry mentioned above had been abandoned as a result of front axle and U.J. failure, criticism of articulation, power performance in comparison with British trucks, and further criticisms backed with the Farnborough tests that resulted in the decision that a 6 x 4 with both rear axles driven was preferable.

On 6 January 1941, Millman sent a note to a Captain R.P. Breindahl requesting that a C.D. [Contract Demand] made up for the construction of a pilot model 6 x 6 special DND pattern vehicle by GM of Canada for $15,000. The production model represented by the pilot was to replace the then present 6 x 4 special DND pattern vehicle. The new truck was to have an engine of considerably more power than the 6 x 4 with three driving axles in place of two, one piece side members, a greater load carrying capacity, improved cross-country performance and ‘increased stamina’. C.D.L.V. 346 40/41 was then issued and forwarded to the Treasury on 8 January 1941.

On 10 May 1941, the DND H.Q. in Ottawa cabled the Canadian Military H.Q. in London in response to the latter’s # T.A. 260 to advise that a 6 x 6 GMC truck with an engine producing 216 lbs./ft. of torque was being developed. A new cab and sheet metal was designed to take this engine, which was the largest that could be used with the then current axles. This would not enter production prior to January 1942 at which time the 6 x 4 [F.60H] would be discontinued. There were approximately X50 6 x 4 trucks to be built which would fill all then presently known requirements. Ottawa had sent a Telegram MECH 1503 on account of criticism in Canada of lack of performance and because the RCAS.C. in Canada stated that they required a 16 or 17-ft. workshop body to carry more complete equipment tan specified for corresponding English {sic.} vehicles hence the MECH 1806. The proposal regarding alternative vehicles mentioned in the MECH 1503 would involve cancellation of as many 6 x 4 trucks as possible, the exact number depending on availability of larger chassis. The reply should therefore cover the suitability of the then present 6 x 4 with load and wheels as specified in MECH 1503 for both MGO and RCAS.C. requirements and the advisability of the introduction either of the heavier chassis previously mentioned.

On 21 May 1941 the Directorate of Mechanization drew up a General Specification for a Chassis and Cab for a Mobile Workshop. The Specification called for either 6 x 4 or 6 x 6 drive, C.O.E. and r.h.d. preferred, with a minimum of a 320 cu. ins. capacity engine. The P.T.O. was to drive a 7½ kW Generator.

Colonel R.A. Macfarlane, the Director of Mechanization wrote on 3 July 1941 in reply to the Quartermaster-General’s [Q.M.G.’s] memorandum of 30 June regarding Q.M.G. workshops. In accordance with agreed procedure, the engineering section had developed a specification of the desired chassis for workshops. The Motor Vehicle Controller then put out enquiries to the different manufacturers who could approach the specifications.

.....On 11 September 1941, an all-day test of the pilot GM C.60X was conducted and the Director of Mechanization and Director of the MGO Branch went on record that the vehicle was not satisfactory for capacities in excess of 18,000 lbs. G.V.W...

It appears that Contract Demand or C.D. LV 407 was issued for GM C.60X production trucks as follows in December 1941:

LORRIES, 3-ton, 6 x 6
Stores 200
Machinery Type A 36
Machinery Type B 3
Machinery Type D 3
Machinery Type D 1 5
Machinery Type F 5
Machinery Type H 3
Machinery Type I 12
Machinery Type IL 6
Machinery Type I30 6
Machinery Type J 12
Machinery Type K 12
Machinery Type M 189
Machinery Type Z 8
TOTAL 500

The problem was that further experiments were being carried out to determine which chassis were to be used for which purposes as C.D.L.V. 405 and 406 had been issued for 600 4-ton 6 x 6 and 20 Breakdown Tractors respectively, and 351 for 50 Breakdown Tractors though Berry was notified on 5 December that an additional 400 4-ton 6 x 6 lorries were required. Colonel Macfarlane, D. of M. commented that they were unable to spread their C.D.s between the type to be supplied on GM 6 x 6 and the type to be supplied on 4-ton 6 x 6 similar to the White.

The first General Motors [not Chevrolet] C.60X was intended to be produced in April 1942, and Chrysler of Canada agreed that they would outfit the special chassis required to complete the pressing requirements. There is no evidence that any C.60X chassis were supplied to the British Ministry of Supply direct although S/M 2510 was for 60 C.60X chassis for Australia and these were delivered by 1 October 1942.

Canadian order F60H production ended on 14th August 1941 by the way.

These are the earliest C60X lorries I know of:

2886016857 ENGINE # 270 148658 C.D.L.V .587 AUGUST 10 1942
2866016873 C.D.L.V. 587 AS WELL?
2866016880 C.D.L.V.587 AS WELL?

2866030148 ENGINE # 270 197,664 C.D.L.V. 1516 DECEMBER 11 1942
2866030207 ENGINE 270 202,997 JANUARY 7 1943

[Geoff Winnington-Ball (RIP)]

David, did it ever occur to you that you know too much for your own good?

[David_Hayward (RIP)]

I cut this posting down...but it is a burden having all this stuff in my brain! Here's an article I wrote for HERITAGE COMMERCICALS that may interest:

http://www.gmhistorian.btinternet.co.uk/f60h.htm

[Brian Gough]

Hi David (and Keith & ramtank2),

GM Service Bulletin B-30 dated Dec. 16, 1942 may help you here. Item 69 documents the installation
of the Publications Plate (Maintenance Manual and Spare Parts List) on each vehicle. It says in part:

" This plate was added at the following Serial Numbers:-

Canadian Military Pattern 6 x 6 - start of production) 2866010752 ...... "


My guess is that serial number would have a build date in the period late May - early June, 1942.

HTH. Cheers,

Brian

[David_Hayward (RIP)]

There was a change on the windshield centre post: before # 2866010751 bolts were welded on and after this number studs were welded on. It would appear that at that time the info plates were changed as well. I wonder if that was a change in contract ? CDLV 407 to 587?

[ramtank2]

Thanks guys great info.

[Leo Blekkenhorst]

Just came across this thread searching for C60X related articles.
My unit has a build date of June 1942. I'll attach a picture of the tags.
PS looking for Cab for this unit somewhere in Ontario or Manitoba if anyone has something that will fit...
Thanks
Leo Blekkenhorst