Specifications of 50 famous racing engines up to 1994

[Tommy Cookers]

WW2 aircraft engines eg Merlin and Allison had in their induction systems 'backfire (flame) traps'
necessary to carburettor-suction highly supercharged engines with large valve overlap
in the 1930s Italian racing (sea)planes and their pilots were afaik lost because they didn't have such trapping

[saviour stivala]

These old notes are much more extensive then what is given here, they cover mostly the whole car development of that particular year. But only important notes of interest on engine development that leads to its specification were concentrated upon. Some more important notes that might interest some on this 1937 Mercedes-Benz were.
Tests results carried out. “pressure carburettors”:-3000RPM BOOST 6.2PSI AT VALVE 316BHP/750Nm torque. At 5800rpm 13.3PSI AT VALVE 550BHP/675Nm TORQUE. “suction carbuettors”:- 3000RPM 10.2PSI AT VALVE 361BHP/857Nm TORQUE. 5800RPM 11.3PSI AT VALVE 556BHP/683Nm TORQUE.

The "Pressure Carburettor" (downstream of the supercharger) was favoured (by most teams) for many years, the reason stated being "better throttle response". The suction carburettor is superior in almost every other respect and the difference in throttle response could not be more than perhaps one revolution of the engine - scarcely detectable.

“These old notes are much more extensive” Here is one more example, an extract example from 1955 M-B M196 2.6-l eight. “From a shopping list of 25 different fuel blends supplied by ESSO, 7 were tested, the best results, as a combination of power with fuel economy, were given by blend RD1, which contained 45% Benzol, 25% Methyl alcohol, 25% 110/130 Octane gasoline, 3% Acetone and 2% Nitro-benzene. Resistance to knocking at 12.5:1 compression ratio used was increased by addition of 0.03% by volume of Tetra-ethyl lead. Nitromethane additives were tried but not used because they were knock-sensitive.

[Tommy Cookers]

“These old notes are much more extensive” Here is one more example, an extract example from 1955 M-B M196 2.6-l eight. “From a shopping list of 25 different fuel blends supplied by ESSO, 7 were tested, the best results, as a combination of power with fuel economy, were given by blend RD1, which contained 45% Benzol, 25% Methyl alcohol, 25% 110/130 Octane gasoline, 3% Acetone and 2% Nitro-benzene. Resistance to knocking at 12.5:1 compression ratio used was increased by addition of 0.03% by volume of Tetra-ethyl lead. Nitromethane additives were tried but not used because they were knock-sensitive.

Ho-hum !
Benzole was English for a benzene, toluene, and xylene mix (traditionally from distillation of coal tar)
110/130 ? global avgas specs were green 100/130, brown 108/135, and purple115/145 (though 110/130 counted as 100/130)
avgas would contain a lot of benzene, toluene, and/or xylene anyway
methyl alcohol has about 11% more heat (eg for 2498cc of MB air) than gasoline or its avgas fellows as above
acetone was for blend stability to prevent precipitation in a gasoline/alcohol blend of water carried by the alcohol
nitrobenzene at this level mainly a combustion accelerant

in 1958 100/130 (100L) avgas became mandatory for F1
(now 100L avgas has been replaced by blue 100LL - less TEL but still quite a lot)

[gruntguru]

In the old days German racing engine makers preferred practice especially that of Porsche was to quote valves events/duration/opening and closing duration/seat-to-seat with a tappet clearance of 1.0mm and not at a certain lift. That does not mean that they ran their engine with a tappet clearance of 1.0mm. tappet clearance was as is logical, arrived at parts involved expansion calculations necessary to keep valve firmly closed on seat with minimum clearance between cam base circle and tappet. Tappet clearance is something that drastically effects seat-to-seat duration, but noise and valve clatter is of minimal importance in a racing engine

Seat to seat valve timing measured with tappets set to 1 mm is the same as valve timing measured at 1mm lift (and tappets set to zero clearance.)

[saviour stivala]

That is exactly why that while others were lost debating between themselves at what lift a cam duration should be calculated at from the early time German race engine makers were using that system. “Duration seat-to-seat with tappet clearance set at 1.0mm”. Although I do not have any notes about it having been used as a fact by German engine makes of old, I do use the “1.0mm tappet clearance” when I calculate and make a master at a targeted duration on the manual tools I have for making my working scale models camshafts, that system lets me adjusts by tappet clearance by manipulation individual cam-lobes duration as well as equalizing them and still retain some clearance while valves are on seats.

[saviour stivala]

In the old days German racing engine makers preferred practice especially that of Porsche was to quote valves events/duration/opening and closing duration/seat-to-seat with a tappet clearance of 1.0mm and not at a certain lift. That does not mean that they ran their engine with a tappet clearance of 1.0mm. tappet clearance was as is logical, arrived at parts involved expansion calculations necessary to keep valve firmly closed on seat with minimum clearance between cam base circle and tappet. Tappet clearance is something that drastically effects seat-to-seat duration, but noise and valve clatter is of minimal importance in a racing engine

Seat to seat valve timing measured with tappets set to 1 mm is the same as valve timing measured at 1mm lift (and tappets set to zero clearance.)

What really counts to producing power with engine actually running is seat-to-seat cam-lobe duration. As I said, tappet clearance drastically alters seat-to-seat cam-lobe duration.
And thanks for the interest shown.

[hollus]

1949 Cisitalia 1.5-Litre Flat-12

1949 Cisitalia 1.5-Litre Flat-12: Porsche’s type 360 was a flat “180 degree V12”. This layout allowed the rod big ends of opposite cylinders to share common crankpins. 2 valves per cylinder equally inclined at 90 degrees included angle seating directly on high-silicon Y-alloy aluminum detachable water cooled heads attached with long studs to the crankcase.
Split vertically at crank centerline the crankcase was cast of high-silicon aluminum and formed in 2 halves extending downwards to form the complete sump, finned on the bottom and machined cylindrical hollow. Trapped between the 2 halves at the rear were 3 barrel-shaped spur-gear pumps, 2 sump scavenge and 1 oil pressure driven from rear of crankshaft.
Oil was fed to nose of crankshaft were it passed through a centrifuge before being fed into delivery drillings the length of the shaft.
Cast-iron wet liners clamped between each head and crankcase were ledged 64mm down into crankcase.
High-peaked forged duralite aluminum alloy pistons with 2 compression rings + 1 oil ring above the gudgeon pin.
Hirth build-up with 1 piece all roller bearings crankshaft with fully circular cheeks. 7 roller main bearings +1 ball bearing at rear to take clutch thrust were used, this ball bearing was placed outboard of the gearing that drove the superchargers and camshafts.
1 piece con-rods with crowded-needle bearings big-end. This bottom-end was designed to be capable of better than 10000RPM.
Next to the rearmost roller main bearing a spur gear drove-up to another gear which drove a bevel gear, other bevels at its sides drove shafts running at engine speed which extended out to the inlet valve housings where a half-speed bevel pair drove the inlet camshafts, from inlet cam drive was taken downwards to exhaust cam. The cams and valve gear were carried in separate light-alloy housings bolted to the head. 2 coil valve springs per valve were used. Cams acted on finger followers.
2 Centric design vane-type blowers having the asset of internal compression set side by side, an idler gear in between allowed the blowers to be handed so that they counter-rotated to suit the induction layout. 2 large-bore Webber downdraught carburetors were used. 2 Bosch 6-cylinder magnetos and 18mm Lodge spar-plugs were used.

Specifications:

Cylinders f12.
Bore 56mm.
Stroke 50.5mm.
Stroke/bore ratio 1.1:1.
Capacity 1493cc.
Compression ratio 7.6:1.
Con-rod length 101.6mm.
Rod/crank radius ratio 4:1.
Main bearing journal 55mm.
Rod bearing journal 54mm.
Inlet valve 34mm.
Exhaust valve 29mm.
Inlet opens 30 degrees BTDC.
Inlet closes 61 degrees ABDC.
Exhaust opens 68 degrees BBDC.
Exhaust closes 22 degrees ATDC.
Inlet pressure 3.07Atm.
Peak power 340BHP@10500RPM.
Piston speed corrected 18.3m/s.
BHP per litre 227.7BHP per litre.

[hollus]

Some links on the 1949 Cisitalia 1.5-Litre Flat-12:

https://bringatrailer.com/2018/07/12/te ... at-12-4wd/

[saviour stivala]

The 1949 Cisitalia (Porsche type 360) was an astonishing engine (actually a car design) years ahead of its time, by a dislodged from its home minuscule design office. No less astonishing is the story (difficult time/period) it came about.

[Brian.G]

This is a great thread!

Brian,

[saviour stivala]

This is a great thread!

Brian,

Thank you Brain, much appreciated, and am sure that hollus will agree, more so from somebody who himself contributed in no small way to the enrichment of likeminded fellow posters technical knowledge.
Few can calculate the pioneering design greatness of this F1 racing car that was the end result of a contract signed in 1947 after astonishing contacts made between Turin (Italy) and Gmund (Austria) during the prime of confusion that was 1946. This contract resulted in a mid-engined F1 car with selectable by driver 4WD with a sequential gearbox an all roller and ball bearing 1.5-litre flat-12 engine having a crankshaft nose oil feed with a build-in oil centrifuge producing 227.7BHP per litre@10500RPM.
Cheers and all the best for the festive season to all At and On F1technical net.

[dren]

The 1949 Cisitalia (Porsche type 360) was an astonishing engine (actually a car design) years ahead of its time, by a dislodged from its home minuscule design office. No less astonishing is the story (difficult time/period) it came about.

A truly amazing car design for the time. It had a 5 speed sequential gearbox with synchros and a driver selectable 4WD system that could decouple the front drive. It was a true mid-engine design with the gearbox before the differential. Edit: I see you posted most of this already just above, sorry for the duplicate information! I will add another picture, though:

[saviour stivala]

The 1949 Cisitalia (Porsche type 360) was an astonishing engine (actually a car design) years ahead of its time, by a dislodged from its home minuscule design office. No less astonishing is the story (difficult time/period) it came about.

A truly amazing car design for the time. It had a 5 speed sequential gearbox with synchros and a driver selectable 4WD system that could decouple the front drive. It was a true mid-engine design with the gearbox before the differential. Edit: I see you posted most of this already just above, sorry for the duplicate information! I will add another picture, though:
https://i.pinimg.com/originals/93/2c/9f ... 455ca6.jpg

Thanks dren for a nice picture. looks like in 1949 brake coling ducts were already in use.

[J.A.W.]

Honda dyno chart showing G.P. engine outputs of various 2T configurations from ~1/4 century ago.
( 500/V4; 500/V2; 375/V3; 250/V2.)
See here: https://www.kiwibiker.co.nz/forums/atta ... 1546116747

[hollus]

1950 Maserati 4CLT/48 1.5-litre four

1950 Maserati 4CLT/48 1.5-litre four: 4CLT/48 actually referred to the complete car the “T’ referring to the new tubular chassis/tube frame instead of box-section of the previous year car, the new car was nicknamed the ‘San Remo’.
The 4CL engine was of ‘square’ cylinder dimensions (square stroke/bore ratios). 4 valve per cylinder equally inclined at an included 90 degrees with port faces sloping out at same degree, 8 individual openings on each side. Valves were closed by coil springs and opened by finger followers.
2 Heads and blocks of 2 cylinders each cast integral and made of aluminum with dry steel liners. Twin overhead cams turned by forward located gear train that also drove 2 blowers at engine speed one above the other pointing forward.
3 bronze backed main bearing crankshaft, no separate main bearing caps were provided. Crankcase was split horizontally to receive the crank. Split 2 bolt cap con-rods were used babbit bearing metal was poured directly in all bearings. Lubrication was dry-sump.
A big Twin throat Weber carburetor fed by big bottom primary blower with boost reaching 25psi piped through a single log manifold. The water pump was driven from secondary blower.

Specifications:

Cylinders l4.
Bore 78mm.
Stroke 78mm.
Bore/stroke ratio 1:1.
Capacity 1491cc.
Compression ratio 6:1.
Con-rod length 161mm.
Rod/crank radius ratio 4.1:1.
Main bearing journal 62mm.
Rod journal 52mm.
Inlet valve 40mm.
Exhaust valve 40mm.
Inlet pressure 2.72Atm.
Engine weight 165kg.
Peak power 260BHP@7500RPM.
Piston speed corrected 19.2m/s.
BHP per litre 174.4BHP per litre.
Engine weight per BHP 0.64kg per BHP.