Vintage Thing No.87 - SUMB 4x4

This SUMB turned at Boconnoic this year

After all that effort on the Candidi Provocatore Allard to change its engine I began to wonder how a side valve Ford flathead engine could still be churned out by a factory in Clermont-Ferrand in 1991. Rob's description of a four-wheel drive NATO Simca rang a distant bell and I referred to my copy of The Observer's Military Vehicles Directory by Bart Vanderveen.

Under France: Trucks, ½ to 2 ton, 4x4, I found the Simca-Unic-Marmon-Boucquet MH600BS. It's a bit of an ugly thing but that's okay with boonie bashers. The engines listed for this device is listed grow in stages from the original 3622cc via 3923cc litres to 4184cc. They still only put out 100 bhp, though, so any excitement is tempered somewhat, but still - phwaor, though, eh?.

So who were Simca, Unic, Marmon and Boucquet?

I'd heard of the first three.

Simca was set up in 1934 to produce Fiats in France under licence and subsequently bought truck manufacturer Unic in 1951 and the French Ford factory in Poissy in 1954. Marmon Herrington had been converting Ford cars and light trucks to four wheel drive since before WW2 amd M. Boucquet was president of the French wing of Marmon-Herrington, which later became Marmon-Boucquet. 

M. Boucquet was the man behind the SUMB MH600BS, which entered production in 1962 for the French Army, replacing WW2 US-built Dodges. There were contemporary Renault designs as competitors to the SUMB and Simca trucks powered by diesels but somehow the the petrol engined trucks remained in favour. 

Flicking through the pages of this august tome, I see that 3923cc versions were also available (bore and stroke of 80.97 x 95.23mm) and that some Marmon-Herringtons even had an air-cooled Panhard flat four of 1996cc (85 x 88mm) that rather tellingly put out 90 bhp i.e. about the same as the flathead of twice the cubic capacity. I doubt that it burbled so nicely, though.

Transmissions were usually four speeds, sometimes with a two speed transfer box.

This Simca Cargo 3 ton French Army truck used another variant of the Ford flathead V8 (Photo: Wikipedia Francais)

But these flat fours weren't in production as long as the old flathead V8, which seems to have been a cheap engine to build after World War 2, as it powered Ford and Simca trucks throughout the fifties and sixties but became more expensive to run as fuel costs increased. 

SUMBs were in production until 1971 and their off-road performance was so effective that the French Army kept them going right into this century. In a marvellous example of Gallic stubbornness, it wasn't until 1999 that remaining examples of the darling of Les Soldats got a startling rebuild with a Renault 3.6 litre 4-cylinder turbo diesel and a 5 speed box. 

I get the impression Renault must have wanted to do this hop up for years. Replacing the whole vehicle must have been even more to their taste but that was too much change all at once for the French Army. 

From looking closely at the photos in Mr Vanderveen's directory it appears that the SUMBs had step down axles, which incorporate gears in the hubs to lower the hub/raise the axle and diff to increase ground clearance, while the Renaults did not. Perhaps it was this feature that ensured such a long life.

Or maybe the French soldiers just preferred the flathead burble.

Diesel-powered SUMBs are now available from military surplus sales and more detailed information on the French variety of Ford flathead V8s can be found on the flathead discussion group.

This Simca-Unic-Marmon-Boucquet MH600BS made it to the US where its unified (non-metric) nuts and bolts were probably much appreciated. (Photo: usmilitaryvehicles.com)