naturally aspirated 3.0l V12 by todays standards

[J.A.W.]

Are you sure they used journal bearings? I would have thought roller bearings would have been more appropriate, unless of course I am missing something here.

Yes, quite sure.

https://en.wikipedia.org/wiki/Fluid_bearing

Oh no.. not wiki.. on a respectable 'technical' forum..

Anyhow, those 2T bike mills - N/A specific output champs of G.P. racing - did use rolling element bearing cranks..

[wuzak]

Oh no.. not wiki.. on a respectable 'technical' forum..

For a quick and easy response.

Anyhow, those 2T bike mills - N/A specific output champs of G.P. racing - did use rolling element bearing cranks..

That would be, I suspect, related to the crankcase induction paths used, and the need to use a fuel/oil mix to lubricated the bearings.

Had they been able have the bearings sealed from teh induction path they would have been able to use plain bearings with pressure lubrication.

[J.A.W.]

Actually W.....,
Teh built-up rolling element G.P. bike crankshafts.. not only functioned well on mist lubrication..
(thus rendering a dedicated/complex/power-sapping/pressurized oil circulation system needless)..
& at the still un-matched N/A G.P. specific-output tq/hp levels generated - but did so, - quite reliably too..

Also, 'kebab' type pressed together construction.. conveniently allows the fitment of low-drag labyrinth seals in-situ..

[PlatinumZealot]

.....The advantages of direct injection (over MPFI) in regards to power are huge.
....could run a higher compression ratio and not have to worry about engine knock. Higher compression ratio = more power
Mazda's new skyactiv technology (uses DI on petrol engines) and enables compression ratios of 13:1 ..... Dirt bikes made by ktm and yamaha are pushing 14:1 + on their 250cc four strokes also using fairly ordinary materials (AND no pneumatic valves either) well...
This is also assuming fuel hasn't change octane rating...
In terms of engine weight well steel crankshaft is the Achilles heel of lightweight engines in f1. Get rid of that and replace it with something a lot lighter and that 95kg engine will be down to about 85kg.
Lighter crankshaft would also have lower rotational inertia so more power to the wheels there......it's pretty hard to beat magnesium and there have been a lot of breakthroughs in making it corrosion resistant .... and neutralizing it's spontaneous combustion properties (by adding silicon molecules I believe)
http://www.gizmag.com/stainless-magnesi ... ash/28856/
If it's possible to make an engine block out of stainless magnesium .... easily supersede steel, cast iron, aluminium, titanium and beryllium too (an illegal material in f1 atm).

(sorry about the quote chopping) ....
we know ....
the later N/A engines used about 95 Octane (the full 101 Octane is not needed at such high rpm, and combustion speed is more important)
and their CR was limited by the valve-piston clearance volume (c. 98 bore 41 stroke makes this worse than Mazda and dirtbikes examples)
super DI most beneficial in an engine where the CR is at the limit driven by detonation
where it is not DI may improve efficiency without improving power
Cosworth said (of their last engines) that PI gave better charge conditioning than DI (helping combustion speed/consistency imo)
BMW tried DI (was it raced ?)

density, specific strength, and specific stiffness of the useful engineering metals are closely related (except beryllium's)
the crankshaft is made from the strongest material - to minimises its journal diameter and velocity so giving the least bearing friction
probably the worst place to use a lighter material

Are you sure they used journal bearings? I would have thought roller bearings would have been more appropriate, unless of course I am missing something here.

Not directed at me but yes. Almost every single piston Engine use journal bearings on the crankshaft. Hydronamic lubrication is a good solution for engines. Low space requirements, low friction, good dampling.. but most of all how are you going to fit a roller bearing on a crank shaft journal?! Remember journal bearing have shells.. Most roller bearings the race is pressed on and is in one piece.

[Tommy Cookers]

how to fit a roller bearing ? ........
almost always by having a multipiece crankshaft that is built-up by installing a bearing, then a crankshaft part, then a bearing etc etc
4 stroke GP motorcycles used them into the late 1970s (MV Agusta)
otherwise the Honda RA 273 (Surtees era) seems to have be the last in F1
the motorcycles, the RA 272 and 273 and the M-B W196 had central power takeoff, afaik 2 shafts coupled at the engine's centre
most earlier GP cranks had only camshaft drive centrally, this coupling allowing central roller main bearings (end mains roller also)
the Ferrari 312 and its emulators eg Alfa and Tecno had roller or ball main bearings only at the ends

the rollers or balls can be run directly on the crank and rods ......
so a single eg Guzzi did this on a 1 piece crank (uncaged or cage assembled in situ)
and a few conrods have managed split big ends with roller bearings (V4 350 Jawa GP 2 stroke ??)
or split races
outboards have used 1 piece cranks with conrods precision split by fracturing

this is a good read
http://www.epi-eng.com/piston_engine_te ... issues.htm

EDIT fwiw I think that built-up construction must be in some way be bulkier and tend to degrade the natural frequencies
because of this it seems to demand central power takeoff, which adds bulk and weight to our car
this was immaterial to the 196 (designed for 4wd and full-width body) and the 272 (transverse engined)
we might think a 9 main bearing st 8 or 7 main bearing V12 types tended to somewhat disproportionate bearing losses (if not roller)
presumably today's very large bore:stroke ratio sets different problems to the built-up crank designer

btw regarding Wuzak's following post, the DB 601/5 certainly had roller big ends

[wuzak]

how are you going to fit a roller bearing on a crank shaft journal?! Remember journal bearing have shells.. Most roller bearings the race is pressed on and is in one piece.

[wuzak]

As an aside, Daimler-Benz V-12 aero engines, at least the DB 601 and DB 605, used rolling element bearings on their crankshafts, not sure if it was for all or just the mains.

Pretty sure their crankshafts were one piece.

[wuzak]

Actually W.....,
Teh built-up rolling element G.P. bike crankshafts.. not only functioned well on mist lubrication..
(thus rendering a dedicated/complex/power-sapping/pressurized oil circulation system needless)..
& at the still un-matched N/A G.P. specific-output tq/hp levels generated - but did so, - quite reliably too..

Also, 'kebab' type pressed together construction.. conveniently allows the fitment of low-drag labyrinth seals in-situ..

Power per capacity is really not the best measure.

I'm sure they could have made more power had they not been burning fuel contaminated with oil.

[strad]

Wuzak I was going to mention outboards.
I know Mercury outboards used something similar to that picture.

[J.A.W.]

Actually W.....,
Teh built-up rolling element G.P. bike crankshafts.. not only functioned well on mist lubrication..
(thus rendering a dedicated/complex/power-sapping/pressurized oil circulation system needless)..
& at the still un-matched N/A G.P. specific-output tq/hp levels generated - but did so, - quite reliably too..

Also, 'kebab' type pressed together construction.. conveniently allows the fitment of low-drag labyrinth seals in-situ..

Power per capacity is really not the best measure.

I'm sure they could have made more power had they not been burning fuel contaminated with oil.

"Power per capacity isn't..." but hey W...., isn't - specific output - the standard motorsport "best measure"?
(Well, until the current economy/efficiency-based rules took over)..

& in fact W....., a heavier lube-to-oil ratio ( ~18/20-1) gives best power output.. due to more effective sealing..

( AFAIR, didn't Rod Banks get the the "best power" out of the R-R type-R V12 race mill - on a special fuel
cocktail - that included 5% castor oil, for that reason?)

The early D-B 600-series V12 aero-mills did use roller bearings on their 'knife 'n' fork' conrod/big ends too,
before being replaced in later series by plain bearings for economy reasons, which gave reliability problems..

Big piston aero-engines were always fairly liberal in oil consumption - anyhow,..

[J.A.W.]

Both the successful & highly-developed 4T V-twin race bikes.. H-D XR-750 ( with 'knife & fork' roller crank-pin),
& the Ducati Superbike racers ( until the new 'Panigale' - a computer cost saving exercise)..
.. utilized rolling element crankshafts..

I recall that Timken did a design study which showed that significant efficiency gains could be had from a
modern dedicated R-E engine design, including friction/heat & lube-pumping loss reductions..

[wuzak]

The early D-B 600-series V12 aero-mills did use roller bearings on their 'knife 'n' fork' conrod/big ends too,
before being replaced in later series by plain bearings for economy reasons, which gave reliability problems..

Because the --- got blown out of the bearing factory and their mission to Sweden to buy bearings was beaten by a few hours by a British delegation who had flown in on a BOAC Mosquito.

And no, I haven't heard of any issues with the plain bearings on the Daimler-Benz DB 600 series.

[PlatinumZealot]

how are you going to fit a roller bearing on a crank shaft journal?! Remember journal bearing have shells.. Most roller bearings the race is pressed on and is in one piece.

http://img.everychina.com/nimg/f8/8a/59 ... ddb122.jpg

Yes I know those bearings. nothing new and I am not phased by your "gotcha post." Those are some giant bearings, not for the speed and load of high rev engine. They are also angular contact. They are made to resist both radial and axial. Not the most elegant solution for a journal bearing. I actually discussed some of these detail in the original version of my post, but I edited that out to prevent confusion for other readers.

You can't just post a picture and expect to be correct though. You have to explain their application somewhat.

Also you can check SKF's website to see what is lost when you make the roller bearing like that. Remember now that roller bearing take up a lot of space too.

Is an interesting topic.. maybe for another thread but I would love a discussion on this.

[J.A.W.]

The early D-B 600-series V12 aero-mills did use roller bearings on their 'knife 'n' fork' conrod/big ends too,
before being replaced in later series by plain bearings for economy reasons, which gave reliability problems..

Because the --- got blown out of the bearing factory and their mission to Sweden to buy bearings was beaten by a few hours by a British delegation who had flown in on a BOAC Mosquito.

And no, I haven't heard of any issues with the plain bearings on the Daimler-Benz DB 600 series.

The RLM (Nazi Air Ministry) certainly were critical of the DB 605's reliability - due to those plain bearing/lube issues..
Although introduced into service in 1942, the DB 605 was, as a result, needfully de-rated right up until '44..
& note also, the Schweinfurt ball-bearing output was largely unaffected by Allied bombing until well into `44..

Ironically, Sweden was a buyer/user of the DB 605, for use in their SAAB fighter plane.
Dunno if the Swedes specified use of the roller bearing crankshaft - in their units..

[gruntguru]

how are you going to fit a roller bearing on a crank shaft journal?! Remember journal bearing have shells.. Most roller bearings the race is pressed on and is in one piece.

http://img.everychina.com/nimg/f8/8a/59 ... ddb122.jpg

. . . . They are also angular contact. . .

Spherical Roller actually. Self-aligning being their main feature.