Can someone tell me the general internal dimensions of the current crop of 2.4 V-8's? Bore/stroke, rod length, crank rod and main diameters/widths, etc. I realize that the actual dims will vary by manufacturer (and kept secret). I'm more interested in general information.
Also... Is the basic architecture of an F-1 engine like a "typical"
DOHC V-8? Specifically, do they have "normal" crank bearing caps? How many bolts per main? Are the heads bolted to the deck in the normal way? How many bolts?
Thanks... doing some musing and need a bit of data to make it more fun...
Although I can't find it offhand - a generous contributor posted an original blueprint of the Cosworth DFV - 3000cc V8 - someone is sure to remember where it is in the Forum index.
Haven't seen a 2.4L V8 F1 engine, but I'd venture a guess that the bore/stroke ratio is around 2.0. That would give you a bore diameter of about 92mm and a stroke of about 45mm. The rules limit bore size to 98mm, bore centers to 106.5 mm, and engines must weigh at least 95kg. For 2008 and beyond, rpm's are limited to 19,000, which would yield mean piston speeds of around 28 meters/second.
The rods are as short (and thus as light) as possible, to minimize recip inertias. They must be one piece uppers, made of steel or titanium, by regulation.
The cranks must be made from a ferrous based alloy, and cannot use any ballasting materials that exceed 19,000 kg/m3 density.
I'm pretty sure that the crank and rod bearings are still journal types. Their sizing being based on the recip inertia loads of the rod and piston assy, as opposed to the combustion loads.
The cylinder heads use studs, usually 4 per cylinder.
The main caps are usually part of the (girdle) sump casting.
The most challenging aspect of F1 race engine design is typically getting an engine structure that keeps the cylinder bores, main bearings and cam journals round and colinear, since the engine is a stressed part of the chassis. The chassis torsional and bending loads can cause a lightweight engine structure to tweek itself all out of shape, causing seizure of any rotating parts.
The most challenging aspect of F1 race engine design is typically getting an engine structure that keeps the cylinder bores, main bearings and cam journals round and colinear, since the engine is a stressed part of the chassis. The chassis torsional and bending loads can cause a lightweight engine structure to tweek itself all out of shape, causing seizure of any rotating parts.
I've sometimes wondered whether with a carbon fibre chassis it is even sensible to expose the block to external stresses? The CoG wouldn't move that much farther back if the engine wasn't a part of the load bearing structure, right? The engines became stressed in an age when carbon fibre in motorsports was unheard of anyway. Especially if F1 adopts the "one engine has to last five races and then some" rule, that'd really speak for doing everything possible to protect the structural integrity of the engine.
getting a metal engine structure to match the stiffness, CTE, etc. of a composite tub is a tall order. Remember a few years back, Ferrari and Honda both tried to do lightweight, thin wall engine block castings in ductile iron, because it's CTE and MoE more closely matched that of a GRE composite tub structure. Most of the teams also played around with thin wall, investment cast titanium gearbox housings for the same reason. Then they discovered Al-Be alloys, with a CTE, MoE, and density approaching GRE composite. Unfortunately, Al-Be alloys cost about $300 per pound, so they were quickly outlawed.
The engine designers got so good at their job, even with conventional materials, that the FIA finally had to impose a minimum weight limit for engines. Can you imagine a 209lb engine that makes over 800hp? And it's small enough to fit in your lap!
riff_raff wrote:Haven't seen a 2.4L V8 F1 engine, but I'd venture a guess that the bore/stroke ratio is around 2.0. That would give you a bore diameter of about 92mm and a stroke of about 45mm. The rules limit bore size to 98mm, bore centers to 106.5 mm, and engines must weigh at least 95kg. For 2008 and beyond, rpm's are limited to 19,000, which would yield mean piston speeds of around 28 meters/second....
I think that I´ve heard somewhere that bore diameters are arround 97mm+ in all F1 engines....
that leaves a bit more than 40,5mm for the stroke
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riff_raff wrote:Haven't seen a 2.4L V8 F1 engine, but I'd venture a guess that the bore/stroke ratio is around 2.0. That would give you a bore diameter of about 92mm and a stroke of about 45mm. The rules limit bore size to 98mm, bore centers to 106.5 mm, and engines must weigh at least 95kg. For 2008 and beyond, rpm's are limited to 19,000, which would yield mean piston speeds of around 28 meters/second.
hi riff raff, just out of interest how do you come to a 92mm bore size? this isn't a criticism! just curious.
".....just out of interest how do you come to a 92mm bore size?"
As I mentioned in my post, it's just a guess. Now it's a rule-limited 106.5mm bore center and 98mm bore dia. But I can't imagine a bore diameter greater than about 92 or 94mm. The stroke ends up being so short that the engine will literally not make any usable power below about 15Krpm. But I may be wrong.
The last time I saw the internals of an F1 engine was about 10 years ago and it was the Zetec V8 from Schuey's Benetton. Big bore, short stroke and short Ti rods. The short stroke, short rods and pneumatic valve springs allowed an impressively small engine package.
I was under the (possibly mistaken) impression that the rods would be unusually long (relative to a typical American V-8) in order to limit piston speed and acceleration. Shorter the rod... the faster the peak piston speed, greater the side load on the piston, etc. etc.
Please clarify. Thanks in advance for the information.
Any comments on bearing sizes. The smaller the diameter, the slower the bearing speed but would require a wider bearing to handle the load. Obviously, the crankshaft would be weaker. Any comments?
the reduced reciprocating mass of a short-ratio rod more than offsets the drawbacks of increased piston accelerations because of that short-ratio rod. But only in a very high revving F1 race engine.
The reduced piston accelerations, and thus lower intake airflow velocities, produced by a long rod-ratio production engine is a better compromise for that application.
In fact, F1 engine rods are designed to be as short as physically possible. The only limit to minimum length being the clearance between piston skirt and crank.
