Standard crankshaft centerline height

[xpensive]

The regulated cylinder-spacing defines the bore, which in turn decides the stroke within a given volume. However, a standard crank centerline height is needed in order to make every engine compatible to different chassis and gearboxes.

[autogyro]

So you are saying that the regulated bore spacing defines the stroke and that this is a longer stroke than that defined by the 58mm crankshaft height regulation?
Have you figures that prove this?

[Edis]

The regulated cylinder-spacing defines the bore, which in turn decides the stroke within a given volume. However, a standard crank centerline height is needed in order to make every engine compatible to different chassis and gearboxes.

Actually, the maximum 98 mm bore limits the bore, which combined with the maximum displacement limits the stroke. Most teams ran around 98 mm when this was frozen and the trend before that was larger and larger bores for each new engine generation.

The mandated cylinder spacing prevent the use of very compact engine blocks. Designs that can be complicated to make.

The engines are not compatible with different gearboxes and chassis anyway, so why should the crank centerline matter for that purpose?

[mx_tifoso]

...

The engines are not compatible with different gearboxes and chassis anyway, so why should the crank centerline matter for that purpose?

While not directly interchangeable I assume that this has led to them being fitted more easily into a different chassis. As was demonstrated by Brawn's use of the Mercedes when Honda pulled out. Was it a few weeks that it took to modify the chassis?

But if the cs centerline wasn't standardized an engine change would have been more time consuming and hence more costly, if not inconsiderable.

[Edis]

...

The engines are not compatible with different gearboxes and chassis anyway, so why should the crank centerline matter for that purpose?

While not directly interchangeable I assume that this has led to them being fitted more easily into a different chassis. As was demonstrated by Brawn's use of the Mercedes when Honda pulled out. Was it a few weeks that it took to modify the chassis?

But if the cs centerline wasn't standardized an engine change would have been more time consuming and hence more costly, if not inconsiderable.

You still need to do the same two basic changes, different crankshaft height or not; the interface between the engine and the monocoque and the interface between the engine and the gearbox.

If the crankshaft centerline differs that would be included in the interface between the engine and the gearbox, the attachment to the chassi would still be the same. In any case, I suspect the changes would include a new gearbox housing for it to match the new engine.

If they wanted engines to be interchangable they would have standardized the interfaces instead with a standardized bolt pattern and so on.

[autogyro]

+1 I agree with your conclusion Edis, however arrived at.
It shows the danger of continuing with standard engine specifications at the expense of the needed development.
F1 does need to control costs but if it does so by using draconian regulations on the powertrain world public interest in the sport will decline.
Increasing interest in alternate energy will see that this happens.

[bettonracing]

I propose that cost was a consideration:

With the CofG incentives of a lower crankcenterline (and resultingly shorter stroke), engine manufacturers would be tempted to develop thinner cylinder walls to accomodate the bore increases (with constant bore spacing).

Regards,

H. Kurt Betton

[xpensive]

Ooops, I forgot that the bore itself was standardized Edis, but that scraps the theory about crank height has anything to do with the stroke then.

I find it obvious that a common crank centerline helps intercangeability between engines, not only for packaging, but calculation-wise as well. As for the interface wich chassis and gearbox, I think those are perhaps the very least of your problems when separate mounting brackets and if needed spacers can be used.

Imagine Ligier going from the fully stressed Alfa Romeo I-4 to a semi-stressed Megatron in 1987? Likewise, I doubt if McLaren built an entirely new tub and gearbox to test the Lamborghini V12 in 1993.

[marcush.]

If they REALLY were into cost reductions ,a mandatory engine gearbox interface
would have done a real step .
cost for a gearbox housing manufacturing when doing an engine swap will be a big obstacle even if you happen to have a mandatory crankshaft height.
Yes of course ,you could resort always to something like an intermediate housing
but of course then you will start with a new wheelbase and inevitably a reduced installation stiffness..

[PlatinumZealot]

The crank height is just the crank height. It stops people from putting the gearbox and engine too low to the ground. Imagine the "oil pan" (well if you call it that, dry sump pan or whatever) for the engine sticking out under the skid board. The crank centre height will also be limited by the gearbox input shaft and the diameter of the gear on it.

[DaveKillens]

The high-revving Formula One engine requires an oversquare configuration. The accepted ratio is over 2:1, so a bore and stroke of 100 mm X 40mm is a ball-park figure. To be more specific, 98 X 39.7.

Considering that the crankshaft is required to be at least 58mm above the reference plane, arithmatic tells me engineers have 18mm to play with. Of course a certain amount of room has to be factored in for the outer shell of the crank rod, oil pan and clearance, but that still allows room to play with.

The same goes with the bore, regulations require a spacing of 106.5mm. Considering that bore is around 100mm, that leaves 6.5mm for the cylinder walls.

No, these regulations do not fix the bore and stoke, there's just too much room to play with. Instead, these rules determine the basic architecture of the engine, and thus force engineers down only one path instead of wasting money pursuing alternatives.

No team will study different engine configurations, no team will study whether to increase the bank angle in order to lower CG, all of that is now closed off. The basic shape of the lump is fixed, and engineers instead have to pursue a path of development and refinement, instead of innovation and experimentation.

5.1 Engine specification :
5.1.1 Only 4-stroke engines with reciprocating pistons are permitted.
5.1.2 Engine capacity must not exceed 2400cc.
5.1.3 Crankshaft rotational speed must not exceed 18,000rpm.
5.1.4 Supercharging is forbidden.
5.1.5 All engines must have 8 cylinders arranged in a 90º “V” configuration and the normal section of each cylinder must be circular.
5.1.6 Engines must have two inlet and two exhaust valves per cylinder.
Only reciprocating poppet valves are permitted.
The sealing interface between the moving valve component and the stationary engine component must be circular.5.3 Engine dimensions :
5.3.1 Cylinder bore diameter may not exceed 98mm.
5.3.2 Cylinder spacing must be fixed at 106.5mm (+/- 0.2mm).
5.3.3 The crankshaft centre line must not be less than 58mm above the reference plane.
5.4 Weight and centre of gravity :
5.4.1 The overall weight of the engine must be a minimum of 95kg.
5.4.2 The centre of gravity of the engine may not lie less than 165mm above the reference plane.
5.4.3 The longitudinal and lateral position of the centre of gravity of the engine must fall within a region that is the
geometric centre of the engine, +/- 50mm. The geometric centre of the engine in a lateral sense will be
considered to lie on the centre of the crankshaft

These regulations pretty well lay out the basic architecture of the engine, and bore, stroke, CG and weight all have limits.

[marcush.]

the Cogheight now is now fixed anyways ,as is the minimum weight for the engine les ancilliaries.

Will it stop someone producing smaller clutches to reduce inertia even more? maybe .
Fact is the more restrictions or specced parts on the car the more teams just have to shift their attention to the non regulated parts..
with the engine thats everything ancilliary as pumps drives ,exhaust,cooling etc.
everything can be improved or new concepts can be developped..less parts but a higher degree of sophistication with potentially less overall gain (pending on the baseline you are starting from compared to others).

[Edis]

Ooops, I forgot that the bore itself was standardized Edis, but that scraps the theory about crank height has anything to do with the stroke then.

I find it obvious that a common crank centerline helps intercangeability between engines, not only for packaging, but calculation-wise as well. As for the interface wich chassis and gearbox, I think those are perhaps the very least of your problems when separate mounting brackets and if needed spacers can be used.

Imagine Ligier going from the fully stressed Alfa Romeo I-4 to a semi-stressed Megatron in 1987? Likewise, I doubt if McLaren built an entirely new tub and gearbox to test the Lamborghini V12 in 1993.

If some engine ran 58 mm crankshaft height, and some other say 55 mm, the impact on the engine installation would be minimal. It would really affect nothing else than the gearbox and clutch design, and since it's typically the crankshaft height that is the limiting factor here, it wouldn't be too difficult to shave off a few mm on the gearbox underside with a new gearbox casing and fit a slightly smaller diameter clutch. A new gearbox casing would be needed anyway.

As the engines are fully stressed, where the engine takes the forces from the chassi will be a quite significant factor. Of course, since all engines use the same configurations the differences are quite small. If on the other hand, it included V engines with different bank angles and inline engines it can be quite significant. This is also why inline engines are generally semi-stressed and not fully stressed.

[xpensive]

I think the FIA did the right thing anyway, a common crank centerline height can do nothing but simplify for the interchanceability between engines, when obviously a 3-5 mm difference would change more than the gearbox casing.