..... The tipo 105 3-litre four was the biggest 4 cylinder engine Ferrari ever built ....
there was the 1955 857S and the 1956 860 Monza
both 3431cc via 102mm bore x 105mm stroke
(and presumably a particularly 'short' rod ratio)
the 860 was ineligible for 1956 Le Mans as the 1955 disaster caused prototypes to be limited to 3 litres
(but 1956 Le Mans wasn't a championship race - track improvements brought back championship status in 1957)
the 860 won at Sebring in 1956 and Ferrari won the 1956 championship (of only 5 races)
Last edited by Tommy Cookers on 04 Feb 2019, 11:51, edited 2 times in total.
Why the very long and snaking exhaust pipes? This is not the first engine in this series to sport them, did the rules prevent the cars from exhausting to the sides? It feels like a lot of weight and back-pressure just to put the exhausts in their natural position behind the car.
the sportscar championship (for manufacturers not drivers) started in 1953
Le Mans eg having eg banned open wheel type bodywork for 1952 (and presumably other 'disguised F1 car' features)
I assume the rules required exhaust systems to end somewhere behind the rear axle line
(even GP motorcycles required something like this though megaphone systems helped alleviate the problem)
a 4 cylinder engine at 6000 rpm with 4:1 or 4:2:1 system (or 2 systems each 2:1) would for tuned length effect require ......
for reflection of initial pulse a total length (exhaust port to atmosphere) of 25.5" ...but more usefully ...
for reflection of the reflection of the initial pulse a total length of 77"
etc
a 6 cylinder engine at 6000 rpm with 2 systems each 3:1 would require ...
for reflection of initial pulse a total length of 34"
for reflection of reflection a total length of 102"
etc
the sportscar championship (for manufacturers not drivers) started in 1953
Le Mans eg having eg banned open wheel type bodywork for 1952 (and presumably other 'disguised F1 car' features) I assume the rules required exhaust systems to end somewhere behind the rear axle line
(even GP motorcycles required something like this though megaphone systems helped alleviate the problem)
1956 Novi 3-litre V8: Fred Offenhauser obtained the services of America’s only full-time racing engine designer of the time Leo Goosen and his engineering advisor William Winfield to design a new supercharged V8 for Indianapolis 500 mile race sponsored by Lewis Welch of Novi Michigan.
A compact powerplant by the unusual at the time oversquare proportions for its long and successful design life. A block design of cylinder head integral with cylinders and jackets for a highly supercharged racing engine.
Large oval inlet and exhaust ports curved out and down from valve seats, spark plugs in center of hemispherical chambers, a complex casting by Alcoa, aluminum full-barrel construction crankcase with narrow finned dry sump just below the crankshaft. Also integral was bellhousing, the cases for primary drives to camshafts, blower and accessories plus the main oil and water passages.
3 main bearings as wide as their diameters in steel-backed nickel-babbit bearing shells held by split bronze circular carriers each of which was attached to a crankcase web by 8 studs. The bronze carriers were larger towards the rear of the engine so they could be assembled on the crankshaft, which was then lowered into the up-ended crankcase from the clutch end.
SAE 4130 steel crankshaft of single flat plane layout. Half speed gear pair below crank nose drove big oil scavenge pump and pressure pump supplying oil at 100psi through rifle-drilled galleries. A forward extension from the half-speed gear drove the 6-blade water pump impeller which had 2 outlets producing an internal block pressure of 30psi. 6 bearings supported each of the camshafts which were housed in 2 piece aluminum cases.
A flat-top inverted-cup tappet was used, over 2 coil valve springs. Removable valve guides needed to allow the valves to be installed and extracted were retained by the inner valve spring. The 2 valve per cylinder were equally inclined at an included angle of 84 degrees.
Centrifugal supercharging drive was geared at the rear at 1.25 times engine speed, this drive was stepped-up further at the front by a pair of gears that gave alternative ratios of 5.35 or 5:1. The supercharger impeller had 16 straight blades, which were machined from billet of duralumin heat treated SAE AA2014, later reduced in size to 10 inches. It reached 42000RPM at an engine speed of 8000RPM (equivalent to a tip-speed of 1835 feet per second-Mach 1.67).
3 downdraught carburettors were used. A single Bosch magneto was used. Forged I-section con-rods were used.
Specifications:
Cylinders V8.
Bore 81mm.
Stroke 72.1mm.
Stroke/bore ratio 0.89:1.
Capacity 2972cc.
Compression ratio 9:1.
Con-rod length 139.7mm.
Rod/crank radius ratio 3.9:1.
Main bearing journal 60.3mm.
Rod journal 58.7mm.
Inlet valve 41.3mm.
Exhaust valve 36.6mm.
Inlet pressure 3.4Atm.
Engine weight 266kg.
Peak power 550BHP@7500RPM.
Piston speed corrected 18.8m/s.
185BHP per litre.
0.48kg per BHP.
1957 Maserati 250F 2.5-litre six: The cylinder block extended from centerline of crankshaft to top of cylinders, which were capped by a detachable cylinder head, the top 1/3rd of the block served as an aluminum-alloy coolant tank surrounding 6 nitrided–iron wet cylinder liners, the lower 2/3rds of the liners were a shrink-fit in the block.
7 main bearing caps each had 4 retaining studs. A fully-counterweighted nitrided-steel crankshaft machined from a billet was used.
A deep casting at front bolted to the assembled block-sump unit carried the scavenge and pressure oil pumps, water and mechanical fuel Mona pumps + the helical and spur gear drives to these units and also all fluid inlet and outlets. At front the crank carried 2 helical gears, 1 to drive this unit and the other to drive the gear train in the block. The latter consisted of 2 big drilled gears vertically disposed to drive the 2 pairs of cam-drivegears in the head, plus 2 short longitudinal shafts with bevels which drove the 2 Marelli magnetos.
Very deep Electron sump was divided by a bulkhead into 2 separately-scavenged sections, a longitudinal baffle placed at an angle scooped oil splash off the crank and directed it downwards. The scavenge pump drew from 2 pick-ups. Oil pressure was at 100-110psi. Oil entered the center main bearing from the left and passed on the right hand side. This fed the rest of the mains. BP produced a special SAE 40 oil specifically for this engine, “BP Corsa 40”.
All bottom end bearing shells were Vandervell lead-indium type. The front and rear main bearings were 32mm wide while the 5 inner once were 19mm wide.
I-section forged steel rods with 2 bolts per cup were fully polished with bronze gudgeon pin bushings. The full skirt pistons were made by Borgo and had 2 compression rings and 1 oil ring above the pin + 1 oil ring below it, the rings were by Kiklos.
Helical timing gears all the way up to last idler, shared a shaft with spur-gear that drove camshafts, each cam had 7 babbit bearings.
Pivoted fingers between lobes and valve stem were used. 3 coil springs exerting 136kg closed each valve. Inlet valve inclined 36 degrees from vertical and exhaust 41 degrees. Valve lift was 8mm. 14mm spark plug were used. 3 Weber 45 DCO3 carburettors were used.
Desmodromic valve gear was built and tested as was fuel injection using an OM diesel injection pump with nozzles placed just at top of cylinder wall spraying against the inlet valve, but never raced.
Few engines have been granted a more classic racing status than this Maserati 250F GP racing engine.
Specifications:
Cylinders l6.
Bore 84mm.
Stroke 75mm.
Stroke/bore ratio 0.89:1.
Capacity 2493cc.
Compression ratio 12.5:1.
Con-rod length 143mm.
Rod/crank radius ratio 3.8:1.
Main bearing journal 60mm.
Rod journal 51mm.
Inlet valve 46mm.
Exhaust valve 40mm.
Valve lift 8mm.
Inlet pressure 1Atm.
Engine weight 197kg.
Peak power 290BHP@7500RPM.
Piston speed corrected 19.5m/s.
Peak torque 286Nm@6000RPM.
Peak BMEP 208PSI.
116.3BHP per litre.
0.68kg per BHP.
Edit from hollus: Thank you Wuzak for pointing out the erroneous picture in the original post. I have exchanged it for one showing the installation of the V6 now. Shall we leave this V12 picture here to document my bad google skills and the engine that could (and often was) substituted for the V6?
The 250 F did race with the 2.5-litre V12, It was later enlarged to 3.0-litre with 3 valves per cylinder. And please do leave that V12 picture on the thread.
So I guess the V12 was also what was inside the car in the picture originally posted (below) and now substituted, which made the enegine cover bulge?
According to Wiki:
"In 1956 three 250F T2 cars first appeared for the works drivers. Developed by Giulio Alfieri using lighter steel tubes they sported a slimmer, stiffer body and sometimes the new 315 bhp (235 kW) V12 engine, although it offered little or no real advantage over the older straight 6. It was later developed into the 3 litre V12 that won two races powering the Cooper T81 and T86 from 1966 to 1969, the final "Tipo 10" variant of the engine having three valves and two spark plugs per cylinder."
the 250F car pioneered adjustment (by rear spring guide roller repositioning) of rear roll stiffness
and gave to posterity the false view that drifting is evidenced by countersteering
btw the tipo 8 F1 engine was a 1963 1.5 litre transverse V12 that ('sold' to Honda) led to the 1964 Honda F1 V12 (and Muira)
see maserati-alfieri.co.uk/menotti12.htm
even more than the 3 litre tipo 9 it had rather limiting lowish bore:stroke ratio
(the 2.5 litre V12 having a better 68.7 bore/56 stroke - iirc the design derived from the FB Mondial motorcycle)
interestingly Honda visited F1 at Monza in 1961, then produced a 135 deg V8 F1 engine before their V12 above
btw the lap record for the very bumpy Monza banked circuit stands for ever to Tony Bettenhausen's Novi at over 177 mph
Last edited by Tommy Cookers on 13 Feb 2019, 17:37, edited 1 time in total.
