The collection of relics, many of which were found in the overgrown garden, is expected to fetch hundreds of thousands of pounds at auction later this year.
Philip Absalom, a one-time farmer who amassed the items over the years, died intestate in July aged 83 after a heart attack.
As paths were cut through the tangled shrubbery at his rented mill house in Swallowfield, Berkshire, more relics were uncovered. Felled trees revealed umpteen small stationary engines, a portable fire tender from 1900 and a 1918 Saunderson tractor worth pounds 10,000.
A Fordson tractor, which Mr Absalom bought new in 1938, was also found. But that was nothing compared with the 1925 Chrysler Six car, with bodywork hand- built by Sir Malcolm Campbell.
Later, a well-preserved De Dion Bouton car, which Mr Absalom bought in 1953 for pounds 42 10s, surfaced. He had parked it in the garden, covered it with corrugated iron sheets and left it. Now it is worth pounds 20,000, said John Mauger of auctioneers Thimbleby and Shorland, of Reading, who will conduct the sale on 4 November.
Mr Absalom lived with his brother Fred, who died 17 years ago, and his sister Molly, who died in 1986. 'They did not have a dustbin and nothing was ever thrown away,' Mr Mauger said. 'They were not so much collectors as obsessive hoarders.'
Mr Mauger expects the cars, tractors and stationary engines to fetch more than pounds 125,000, with more money raised from the sale of furnishings and effects.