Specifications of 50 famous racing engines up to 1994

[hollus]

1955 Mercedes-Benz M196 2.5-litre eight

1955 Mercedes-Benz M196 2.5-litre eight: In 1952 50 year old Hans Gassmann was made responsible for racing car design department set-up to create the engine that Mercedes would use in its GP car for the 1954 2-1/2-litre formula. That engine was the M196, a straight eight inclined in the chassis with a drive take-off geared from center of crankshaft, this central gear train also drove the camshafts and engine accessories including injection pump, dual magnetos and water pump + oil pumps.
Historic sketches prepared by Gassmann showed 2 cam lobes controlling each valve, 1 lobe opened it the other a ‘D’ shaped lobe working through an ‘L’-shaped rocker pulled it closed again. Gassmann had revisited the desmodromic valve gear which both Dalage and Th.
Schneider had raced with in 1914 French GP. Because the desmodroic valve system could handle much larger and heavier valves a 2-valve combustion chamber was decided upon.
Forged-steel integral cylinders and heads were used, welded to 1-1.5mm sheet steel water jackets to form 2 4-cylinder blocks, no valve seat inserts were needed in a forged-steel head. Inlet valves with a 10mm stem inclined at 43 degrees angle from vertical and exhaust with a 12mm stem at 45 degrees.
Downdraught inlet porting through top of cylinder head and engine inclined at 37 degrees to horizontal. 14mm Bosch plugs were used. Injector positioned on cylinder wall just below the inlet valve with nozzle angled upwards 12.5 degrees. Fuel flow began 30 degrees ATDC on inlet stroke and continued for 160 degrees.
Mahle forged aluminum-alloy fully skirted pistons, the spacing of top 2 compression rings was wide so that hot gasses do not push their way down past both rings through the injector hole in cylinder wall, 2 additional plain rings above and below the gudgeon pin profiled on their lower faces to act as oil scraper rings.
Hirth built-up all roller bearing crankshaft, sections being held together by differential screw inside each bearing journal. Smaller main bearing journals than big end.
Silumin crankcase with main bearing covers at both ends. The rear cover also had a steady bearing for the output shaft driven from crank center gear. Castrol R was handled by 4 oil pumps, a scavenge pump outside the sump recirculated all the oil every minute at 8000RPM.

Specifications:

Cylinders l8.
Bore 76mm.
Stroke 68.8mm.
Stroke/bore ratio 0.91:1.
Capacity 2496cc.
Compression ratio 12.5:1.
Con-rod length 137.5mm.
Rod/crank radius ratio 4:1.
Main bearing journal 41mm.
Rod journal 55mm.
Inlet valve 50mm with 10mm stem and 12mm lift.
Exhaust valve 43mm with 12mm stem and 13mm lift.
Inlet opens 20 degrees BTDC.
Inlet closes 56 degrees ABDC.
Exhaust opens 50 degrees BBDC.
Exhaust closes 14 degrees ATDC.
In-cylinder direct injection.
Injector nozzle position on cylinder wall below inlet valve, angled upwards 12.5 degrees.
Fuel flow starts 30 degrees ATDC inlet stroke.
Fuel flow duration 160 degrees.
Peak power 290BHP@8500RPM.
Peak torque 248Nm@6300RPM.
Peak BMEP 182psi.
116.2BHP/litre.
0.71kg/BHP.
Piston speed corrected 20.2m/s.
0.71kg/BHP. Engine weight 205kg.

[hollus]

Some links on the 1955 Mercedes-Benz M196 2.5-litre eight:



https://www.ultimatecarpage.com/car/362 ... -W196.html

[Tommy Cookers]

...... Forged-steel integral cylinders and heads were used, welded to 1-1.5mm sheet steel water jackets to form 2 4-cylinder blocks, no valve seat inserts were needed in a forged-steel head ......

though the drawing seems to show valve seat inserts

[saviour stivala]

Yes the drawing shows valve seats inserts but the specifications sheet says valve seat inserts were not necessary. Another engine that did not use valve seat inserts was the 1952 2-litre Kuchen V8, but that was a weak point of the Kuchen because the cylinder head material of the Kuchen was aluminium. What was strange on the Mercedes was the valve stem diameters.

[BobbyBreeze]

I'd love to know how they forged a steel cylinder head with ports and water jackets!? Are there any photos of engine components of these engines around? I'm very interested in them. I believe the 300SLR version used a cast block/head with integral waterjackets.

[Tommy Cookers]

presumably .....

the exhaust valve was sodium-filled for internal cooling (Aston Martin said desmodromic valve seating was poor)

25% methanol and 3% acetone in the fuel was what allowed steel combustion chambers
the 300 SLR had to run on road fuel so needed alloy construction

the 'sports' car rules were conveniently absent for M-B (irritating to Jaguar and others with a production-based approach)

[saviour stivala]

The 1995 Mercedes-Benz M196 2.5-litre eight had both the head and the cylinder liner made in one forging (one piece). They used two separate forgings each consisting of four heads and four cylinder liners. The water jacketing cavities were easy to forge because it was not a closed space, the water jacking open forged space was closed-off by welding 1mm steel sheet on the head water jacketing and by welding 1.5mm steel sheet on the head/cylinder liner water jacketing.
In 1913 DMG (Daimler-Motoren-Gesellschaft) decided to enter the 1914 French grand prix of which the ACF prescribed the limits of 1100kg and a displacement limit of 4500cc, halving the engine capacity in a move to favouring the French manufacturers in the smaller engine capacity. This restriction required an increase in engine speed to 3000-3600rpm. This GP was to be held on 4 July 1914. DMG experience with critical vibrations in the aircraft engines that had been used in 1913 led engine designers under Paul Daimler to a new concept of engine. Steel cylinders were threaded into forged steel cylinder heads with welded-on water jackets for each cylinder, a design that was to remain characteristic of Mercedes-Benz racing engines for decades to come. 4 inclined valves per cylinder operated by 3 cam lobes per cylinder (2 operated each inlet valve and 1 operated both exhaust valves) by forked roller type rocker arm. All drives were from rear of crankshaft. The new engine design proved to be a resounding success. On 15 July 1914 the winning car was made available to the British Mercedes distributor ‘Milnes Daimler LTD’. For display proposes. Following the outbreak of first world war the racing car was confiscated, and served as the technical model for the Rolls-Royce Hawk aircraft engine, while valve assembly was adopted for his first motor by Qwen Bentley.

[Tommy Cookers]

......the head and the cylinder liner made in one forging (one piece). ......Following the outbreak of first world war the racing car was confiscated, and served as the technical model for the Rolls-Royce Hawk aircraft engine .....

btw the 1914 Mercedes GP car had Junkers fuel-injection pumps - writes Thomas Foxworth

the construction (from pre-WW1 aero engines) is also categorised as fabricated (by welding) or 'separate cylinder' type
it (eg Merc aero engines pre WW1) allowed a combustion chamber 'bulged' wider than the bore - so giving bigger valves
(GP's fashion switch from 'narrow angle' 4 valve layout to 2 valve 'wide angle' driven by 1924 GP Fiat depended on this 'bulge')
though many Merc aero engines had cylinders screwed into combustion chambers (R-R used the integral construction)
remember all these engines had low bore:stroke ratio
driven by the 'free stroke' road vehicle taxation and helpful with the low fuel quality ('lead' hadn't been discovered)

fabricated construction meant 'closing' the steel cylinder ('liner') with a steel combustion chamber (with faces for valve seating)
(though some 'closed liner' engines had cast alloy head/jackets eg Napier Lion)
open liner construction required seperate seating ie valve seat insert technology (unless the head was iron)
inserts appeared first in the troublesome WW1-era Siddeley Puma aero engine - the first liquid-cooled ohv light-alloy head
later the 1924-5 Wright T and Curtiss V-1400 and 1926 Rolls-Royce F-X aero engines were properly successful
(ok cast bronze construction was less trouble and needed no inserts - but was prohibitively heavy)
so closed liner construction was obsolescent though its sets of 2 or 3 cylinders allowed efficient on-condition 'ring/valve jobs'

the legendary Offenhauser and its related engines had cast iron integral head/block construction
ok most of the turbocharged Offys had integral light alloy head/block construction (a few cast iron ones were made)
running on largely-methanol fuel of course (NA Offys last won Indy on Avgas in 1949)
and those Detroit V8-generic Nascar engines have thin iron blocks but alloy heads

there was first a 4 valve Mercedes 'M196' - but it combusted badly and the 2 valve desmo got the job

[BobbyBreeze]

It's interesting that Aston thought valve seating was an issue. I doubt they ever got their hands on an engine and Mercedes certainly would have known what they were doing. These motors were known to be very reliable. I found this from another website, unsure about where the information comes from but sounds reasonable to me.

That writes LJK Setright, member of "The Institution of Mechanical Engineers" in his book "Some unusal engines": "The principle of the system distriburion Mercedes-Benz was pretty simple, although it is likely that the materials and technical and human resources used were first rate.

But perhaps the most interesting and unique was the removal of the small final closing spring which had always seemed necessary.

Mercedes discovered that 'leaving a tiny residual clearance of 0.03 mm and in the mechanism by simply leave the "desmo" return valve in the closed position, the inertia of the valve and the gas pressure in the cylinder sufficient to maintain the closed

[Tommy Cookers]

afaik and fwiw

the valve doesn't have to be a perfect seal in a race engine
the Aston Martin designer particularly mentions the edges of the valves (which he would expect to suffer)

a 300 lb 350cc single cylinder race motorcycle always needed the rider's weight on the seat to be bump started
a few years ago I saw a 1960/70s 240 lb 350cc Ducati desmo being easily push started by the rider jogging alongside
(the machine beat all modern Ducatis at a Mallory Park demo day - the rider's an ace)
that is what tells me that the valves didn't seal at low rpm
Vic Willoughby wrote that Ducati's 1956 125 GP machine had 0.3mm valvetrain slack and helper springs were discarded

Norton race motorcycles were using sodium-cooled exhaust valves by 1950 - some drawings show noticeably fat stems

[hollus]

1955 Porsche 547 1.5-litre FLAT-4

1955 Porsche 547 1.5-litre FLAT-4: 1953 was the first year Porsche expressly build as completion car and engine, it was the type 550 mid-engine 2-seater, they competed with push-rod units until the engine intended to power them was ready.
The 1953 first example of Porsche 547 was a radical design by Ernest Fuhrmann, an air cooled twin cam boxer 4 which was destined to serve Porsche in various forms until 1966, ending its career in the type 904 Carrera GTS. Steady increases in engine power outputs were made to power successive generations of Porsche Spyders.
By 1959, when Porsche built a single seater for formula 2 it was producing 155BHP and ran safe to more than 8000RPM; in 1961-2 it powered the F1 Porsche fitted with Kugelfischer fuel injection. 1.6 and 2 litre versions were also produced for both racing and production Carrera models, one powered the 1966 904 with an output of 190BHP.
A 2 piece slit vertically on crankshaft center line crankcase housed a Hirths all roller bearing crankshaft with central gear drive to inlet camshafts on both sides; machined in-between the 2 crankcase halves was a tunnel that housed an oil pressure pump and a scavenge pump double the volume of oil pump.
The center crank gear drove 2 horizontal shafts to left and right out of crankcase that drove the inlet camshafts, a shaft running down from inlet camshafts drove the exhaust camshafts.
Individual aluminum cylinders with chrome-plated bores by Mahle were used, Mahle aluminum alloy deep skirted pistons with 1 oil ring bellow gudgeon pin and 3 compression rings above it, with fully floating gudgeon pin. One piece con-rods. 1 twin overhead cam cylinder head each side each pulled down over 2 cylinders by 4 long studs per cylinder. 2 valves per cylinder each equally inclined at an angle of 39 degrees from cylinder center line.
Hollow camshafts with separately made cam lobes which were keyed to the shafts acting on a pivoted finger follower. Each inlet camshaft drove a distributor which could be driven from the back or from the front of camshaft, 2 spark plugs per cylinder were used.
Fine and deep finning to conduct the cooling air with the total cooling fin area 3600 square inches. Cooling by radial-out flow backward-curved blades double sided fan, drawing air from front and back of engine, with generator in the middle as fan drive shaft and supporting the front and back sections of the fan that fed separate cooling ducts to front and rear opposing cylinder pairs. The fan required 8.8 drive HP@7300RPM.

Specifications:

Cylinders FLAT-4 (boxer).
Bore 85mm.
Stroke 66mm.
Stroke/bore ratio 0.78:1.
Capacity 1498cc.
Compression ratio 9.5:1.
Con-rod length 132mm.
Rod/crank radius ratio 4:1.
Main bearing journal 52mm.
Rod journal 52mm.
Inlet valve 48mm.
Exhaust valve 41mm.
Inlet pressure 1Atm.
Engine weight 102kg.
Peak power 125BHP@6500RPM.
Piston speed corrected 15.98m/s.
Peak torque 129Nm@5500RPM.
Peak BMEP 157psi.
83.4BHP per litre.
0.82kg per BHP.

[hollus]

Some links on the 1955 Porsche 547 1.5-litre FLAT-4:

http://claspgarage.blogspot.com/2013/07 ... st_19.html











https://www.quartoknows.com/blog/quarto ... 550-spyder

[saviour stivala]

Some links on the 1955 Porsche 547 1.5-litre FLAT-4:

http://claspgarage.blogspot.com/2013/07 ... st_19.html
http://3.bp.blogspot.com/-k5SWSUrC5DM/U ... ec33_o.jpg

http://4.bp.blogspot.com/-4Ed5TzvsrMo/U ... 5B1%5D.jpg

https://www.porscheroadandrace.com/wp-c ... V_2917.jpg

https://autogalvuremonts.files.wordpres ... ploded.jpg


https://www.youtube.com/watch?v=nNEVKW5FRRk

https://www.quartoknows.com/blog/quarto ... 550-spyder
https://www.quartoknows.com/blog/quarto ... gwell_.jpg

Prosit hollus for those superb engine pictures/photos/drawing especially the video showing the cam drive. One should notice the hollow cam-shaft with separate cam-lobes and the lobe drilled on its face for lubrication, a cam lubrication system that is still being used on present day power unit camshafts lubrication.

[hollus]

1955 Ferrari 750 Monza 3-litre four

1955 Ferrari 750 Monza 3-litre four:- The main line of development towards the ‘Monza’ was it’s engine by Lampredi designated tipo 105. Head and cylinders in 1 aluminum casting which included the ports, combustion chambers and water jackets.
Separate cast iron cylinder liners were screwed-up into the combustion chambers. Inlet valves were inclined at 45 degrees from the vertical and exhaust at 40 degrees. Shrunk-in inserts seated the valves. 2 spark-plugs per cylinder placed at the fore and aft ends of the chamber. 2 hairpin springs closed each valve.
Separate light-alloy boxes carried the light-alloy guided tappets that had narrow rollers, a pair of coil springs acted against each tappet. 10mm wide cam lobe on large-diameter tubular camshafts running in 5 plain white-metal bearings were used.
Tuned manifolding was used, with the pipes paired 1-4 and 2-3 with the tow joining a single expansion chamber.
Induction was by 2-50DCOA3 Weber twin-choke carburettors fitted with 44mm venturis.
The head-cylinder units bolted directly to a deep Silumin crankcase, with O-rings at bottom of cylinders as a water seal. 5 main bearings available in 4 undersizes were used. The center main bearing was 14mm wider than the others which were 28mm wide.
A forged steel crankshaft was used. Aluminum-bronze Vanderell tin-wall big-end bearings were used also available in 4 under-sizes. 2-bolt caps con-rods were used with fully floating gudgeon pins. Fully skirted pistons with 2 compression and 1 oil ring above the pin and 1 oil ring bellow were used.
A 10mm wide spur gear train from front of crank, the upper gears drove the camshafts and the water and oil pumps which were placed low at front. Dry sump system with 2-pick-up scavenged the front and rear of sump. The scavenge oil pump had 2 idlers, a single idler pressure pump used external and internal piping to carry the oil around.
12 volt generator and a Marelli distributor at each side were also driven from front of gear train. Both a Fimac mechanical fuel pump as well as Autolex electric fuel pump were used.
The tipo 105 3-litre four (more precisely its larger derivatives, the 1955 857S and the 1956 860 Monza) was the biggest 4 cylinder engine Ferrari ever built, it was not the most powerful and neither the most reliable, its big heavy pistons limited its racing speeds to around 7 hours of racing, but it brought great success to both the factory and the many private owners all over the world.

Specifications:

Cylinders l4.
Bore 103mm.
Stroke 90mm.
Stroke/bore ratio 0.87:1.
Capacity 3000cc.
Compression ratio 9.2:1.
Con-rod length 142mm.
Rod/crank radius ratio 3.2:1.
Main bearing journal 60mm.
Rod journal 50mm.
Inlet valve 50mm.
Exhaust valve 46mm.
Inlet duration 310 degrees and 98 degrees of overlap.
Inlet pressure 1Atm.
Engine weight 160kg.
Peak power 250BHP@6000RPM.
Piston speed corrected 19m/s.
0.64kg per BHP.

[hollus]

Some links on the 1955 Ferrari 750 Monza 3-litre four:

https://www.ultimatecarpage.com/car/121 ... Monza.html