Английская Википедия:Chrysler ball-stud hemi
The ball-stud hemi (known internally as A279 and affectionately as the BS Hemi)[1] was an automobile engine designed by Chrysler Corporation in the late 1960s.[2] It never entered production.[3]
Intended to deal with the troubles created by the low-production 426, of which only about 9,000 were built from 1966 to 1972),[4] as well as the different architectures of the higher-volume Шаблон:Convert and Шаблон:Convert B and Шаблон:Convert RB V8s, the ball-stud hemi was to be suitable for high-volume manufacture at low cost while generating high performance.[4] Chrysler hoped to replace three block and two head designs with the ball-stud design.[4] It was to be based on a low-deck block and available in Шаблон:Convert (Шаблон:Convert)[5] and Шаблон:Convert Шаблон:Convert)[5] displacements[4] (and Chrysler considered a Шаблон:Convert,[4] which could have used stock Шаблон:Convert Шаблон:Convert pistons),[5] while the new valvetrain would cut both weight and cost,[4] as well as making it possible to fit it in a greater variety of models.[4]
The A279 initially used the B-block head bolt pattern, which "badly hampered" its exhaust ports,[1] forcing the use of a serpentine flow around some of the outer bolts[1] This was changed late in development,[1] but not before some tooling based on the original design had already been created.[1] This meant the head was not truly hemispherical, but had more intake port area than exhaust (Шаблон:Convert versus (Шаблон:Convert).[1]
Its intake valves were nearer the intake manifold, exhaust valves nearer the exhaust pipes.[1] The staggered "poly" arrangement improves airflow by "reducing valve shrouding and eliminating the sharp runner turns" of inline valve arrangements.[1] It also had equally spaced intake ports (similar to the 428SCJ), thereby achieving "more consistent mixture distribution" than the Wedges.[1] Chrysler used a Шаблон:Convert spark plug, rather than the typical Шаблон:Convert, in an effort to fit it as centrally as possible in the combustion chamber.[1]
The intake and exhaust valves were the same size as the 426's,[6] the Шаблон:Convert intake canted at 15° from the bore centerline, the Шаблон:Convert exhaust at 6°.[6] By contrast, the B-block's were Шаблон:Convert and Шаблон:Convert.[6]
Compared to the wedge, the ball-stud block had two additional clean-out holes to remove casting sand, because the large bore made coolant in the water jacket very significant,[6] and an additional oil drainback hole at either end of the block, due to demand for lubrication of the rocker arms.[1] Suggestions to increase the size of the oil pump pickup to Шаблон:Convert (compared to the 426's Шаблон:Convert) never passed the endurance testing stage.[6]
Pistons were to be cast aluminum.[6] Compression ratio was targeted as 10.5:1; on the surviving engine, it was measured at 9.8:1.[1] Forged connecting rods used the Wedge's Шаблон:Convert hardware, as opposed to the Hemi's Шаблон:Convert, but would nonetheless have been considered high-performance parts.[1]
The intake was to be a single Carter ThermoQuad, of greater flow than any previously used, on a dual-plane intake manifold,[5] while dual four-barrels were never even considered, in the face of toughening emissions standards.[1] A split-level (vertically split, rather than horizontally divided) intake was also experimented with.[5]
Chrysler hoped to have the ball-stud in production sometime between 1971 and 1973.[4] In testing, it proved able to outperform the single four-barrel carburetted A134 440, and lagged behind the eight-barrel A102 426 Street Hemi.[7] About one year of development was put in before the project was stopped, in late 1969.[4] It was a victim of increasing demand for emissions controls and a reduction in emphasis on performance, as the "horsepower wars" wound down.[4] Moreover, Chrysler was suffering "severe financial stresses" that nearly brought the company down,[8] so the new production tooling and facilities were now uneconomic.[4]
Estimates of the number built vary from three to twelve.[4] Only one is known to survive.[4]
See also
Notes
Sources
- Kirschenbaum, Al. "Mopar Mystery Motor". Hot Rod, 3/86, pp. 71–8.
- ↑ 1,00 1,01 1,02 1,03 1,04 1,05 1,06 1,07 1,08 1,09 1,10 1,11 1,12 1,13 Kirschenbaum, p.72.
- ↑ Kirschenbaum, Al. "Mopar Mystery Motor", in Hot Rod, 3/86, p.71.
- ↑ It should not be confused with Chrysler Australia's Шаблон:Convert Hemi-6. Kirschenbaum, p.72.
- ↑ 4,00 4,01 4,02 4,03 4,04 4,05 4,06 4,07 4,08 4,09 4,10 4,11 4,12 Kirschenbaum, p.71.
- ↑ 5,0 5,1 5,2 5,3 5,4 Kirschenbaum, p.78.
- ↑ 6,0 6,1 6,2 6,3 6,4 6,5 Kirschenbaum, p.74.
- ↑ Kirschenbaum, p. 71.
- ↑ Kirschenbaum, pp.71-2.
