REBIRTH OF A 50-YEAR-OLD IS GOING FINE
As we continue to follow New Hollands rebuild of a 1942 N-type in time for Junes Fordson 500 event, Andrew Pearce updates on progress – and theres been a lot of it since the tractors mid-March arrival
THINGS are moving on apace at Basildon. Early April saw the small, part-time team under manufacturing engineering supervisor John Baker stripping and inspecting large chunks of the diminutive Fordson, leaving intact only the transmission, which was quiet and working fine. All the tinwork came off, the engine peered into with a medical-style endoscope, its head was lifted and the steering gear taken apart.
Then sharp eyes spotted something unexpected. Laying the front wheels together showed them to be different. One was a good quality casting with a raised hub; the other a pockmarked job with a lower centre. Reference books suggest both patterns were used around the time of tractor 911363s production, so to save purist argument a fresh (and matching) pair of original-fit wheels were supplied by the tractors previous owner.
Engine work went fairly smoothly. Taking off the sidevalve head revealed very little bore wear, and more importantly, no scoring. Just how worn things are is difficult to gauge as production tolerances at the time were wide, but a check showed cylinders averaging 9thou over nominal size.
A sheared head stud was drilled out and changed, with a UNC-threaded replacement coming straight from todays production line. Then after a general clean-up the head went back on, sandwiching a brand new gasket bought from suppliers in Derbyshire for a highly reasonable £12.00. The only other engine job of any significance was rebushing the water pump spindle and repacking its sealing gland – both the magneto and carburettor were in good order and needed only sprucing up.
There is one residual problem with the motor, though, as John Baker explains. "The valves, springs and tappets are under a plate on the side of the block. We took out all the valves, reground their tips flat and lapped them in. But when we put it all back together, two valves had very wide clearances.
"This suggest worn cam lobes, or possibly that someone in the past had used the wrong followers. But time is too tight to have another cam ground, so weve machined two stem caps to take up the slack. Once the show is over well get to the bottom of the problem properly; as it is, the engine runs fine."
Fifty-odd years of trundling round the south-east corner of Wales had left their mark on the N-types steering, mainly in the front axle centre pivot, the kingpins and steering box. Out at the front wheels the news was not too bright, either; both sets of taper bearings were shot and one had a terminal mis-match between inner and out race angles. But the stub axles were still good, so new bearings and seals all round killed the wobbles.
Plenty of play remained in the steering gear, though. First step in removing it involved junking the original axle pivot pin and turning up a new, fatter one in EN8 steel. The axle support castings holes needed reaming out to take the new pin, and the axle pivot gained an oversize bush to match. New kingpins were machined and bushes made, and to complete the front end, all linkage joints were rebuilt. At the drivers end of the system, the steering box gained a new bush on its output shaft. With all that taken care of, the system was tight and ready for another half-century.
New clothes all round
Now we move into mid-April. All the tinwork had still to be sorted and the whole machine needed to be blast cleaned and painted, so several jobs were on the go at once.
As predicted from the first inspection, rebuilding the moth-eaten fenders turned out to be the biggest single sheet metal job. Progress was slowed by the disjointing effects of shift work in New Hollands tinsmiths shop, but the frames were apart and their panelling eyed up for replacement. Apprentices had been set to stripping paint from the big oval fuel tank before its visit to the blast booth, where it would be tickled by a kinder grit than the stuff used to scour the main structure.
By the last week of the month the tankless, tinless tractor was readied for blasting. All engine ports and orifices were plugged by custom-made plates so abrasive cant get where it shouldnt, and with a helping lift from a fork truck – a worm-type axle stops the N-type from being pushed – the little tractor crossed over to the blast booth.
Three hours later it emerged, flayed back to dull grey steel. A short hop through thankfully dry air took it to the spray shop, where it seemed to vanish among the towering special-build New Holland tractors normally painted there. An hour or so and it re-emerged, sealed against rust by two coats of fetchingly yellow single-pack synthetic primer/filler; the same stuff as used on the production line. After a week or so another time slot popped up so back it was towed for top coating; wartime procedure was to spray everything in one colour, so on went two layers of luscious Fordson dark green.
By now the rebuild calendar stands at May 8, leaving precious few weeks for the rest of the job to come together. John Baker, though, seems confident. *
Next month: The finishing touches.
Fresh bearings and seals cured the Fordsons front wheel wobble.
John Baker (right) and Mick Cronin check blast booth progress while the outside contractor waits. Softer grit was used on the fuel tank, fenders and radiator: The bill came to £250.
The yellow peril? Two coats of production line primer/filler followed straight after shotblasting. Note protective plugs and sleeves around the engine.
Work in progress: New Holland toolroom man Mick Cronin runs a tap down block threads before fitting the rebushed pump.
Reaming the axle support casing to match the new, oversize pivot pin. The axle itself gained fresh bushes, turned and reamed to size.
The N-types worm differential means it cant be pushed, so moving it out to the blast booth calls for a lift truck and helping hand.
Skill and quality machinery is not short in New Hollands toolroom.
Its early May, and the first layer of one-pack synthetic Fordson green goes on. Wartime practice was to spray all parts the same colour, so thats happening here.
A fresh kingpin, complete with grease nipple, goes into its rebushed steering knuckle. All linkage joints were replaced.