Straight Horizontal Engine

[marcush.]

just for the record :at ONE G lateral the oil level would be at 45° from horizontal any more than that and you can be sure of oil being trapped in very unusual places.
Very often not lateral and longitudinal but vertical movements cause the biggest headache ..the old E30 M3s had BIG oil pressure issues at the Nordschleife for example in at least 2 places .

In the end you need to make up your own mind around the oiling and cooling issues arising from a upside down or laid down engine ..
I´m pretty sure oiling considerations were not the main driver for engines being upright or slanted at 45° or whatever -so it pays of to understand the reasons behind the design detail.As soon as you got own experience it will be ratrher obvious when looking at others work in the area -issues like this are not exclusive to certain persons ,they are bound to the engineering exercise you are venturing into. Have fun analysing what cicumstances could avoid oil reaching your pickup in sufficient quantity when it is needed...

[Greg Locock]

re mowog above, no, you missed the point. A bike engine operates mostly with acceleration downwards relative to itself, hence doesn't get oil building up on the sides, whereas a car engine operates with an acceleration vector anywhere from vertical to lateral, relative to itself.

[autogyro]

When I do aerobatics in my mates Tiger Moth I get acceleration vectors all over the place.
Never had oil problems though.
We did change the bottom oil control ring for ones out of a Perkins 4106 diesel though.
Smokes less now.

[xpensive]

re mowog above, no, you missed the point. A bike engine operates mostly with acceleration downwards relative to itself, hence doesn't get oil building up on the sides, whereas a car engine operates with an acceleration vector anywhere from vertical to lateral, relative to itself.

I have yet to see a BMW-rider cornering with any dramatic angle of attack, au contraire, perhaps you missed the point?

@MOWOG; I agree, the arrogance from some of the forum's self-appointed xperts can be both annoying and humiliating.

[Greg Locock]

Ah, you've never seen one so it never happens? First google hit

http://www.kilometermagazine.com/news/m ... cornering/

I suppose that is photoshopped in your opinion.

[munudeges]

Yer, everyone rides like Marc Marquez.

[Steven]

Fortunately this is a forum mainly about cars....
If a motorcycle is not or hardly leaning into a corner, it means either it's driving slow, and in this case, there's also no oil getting squeezed into one side of the engine.

[xpensive]

Not so fast (!), I appreciate the engine in the image above to be slanted at a 45 degree angle, while at the same time centripetal acceleration increases with the square of the velocity, why chances are that the oil will still be forced to the side?

[marcush.]

your motorcycle engine may or may not see sustained gs comparable to a serious car ,but does anyone know how the rate of change compares to a car ? I rarely have seen cars lifting itself on the rear or front wheels during acceleration as well so the story may well be a bit less clearcut than our static approach may lead us to believe?

it still is common practise to have see through gearbox casings to evaluate and understand oil flow and distribution in gearboxes .
Here one example that can be retrieved in the web -rest assured it is still done that ways -you may well invrt the whole thing and see what´s happening or have it tilted sideways or whatever..
To lean back and ask what needs to be done is a simple question but there is surely not a simple answer -and probably there is not a simple solution as well ...even though the really clever solutions in life are strikingly simple -but a lot of thought and understanding only allowed to come to those strikes of genius..

[Greg Locock]

I'll try again with bikes vs cars.

With a bike the rider essentially leans the bike so the resultant vector of the cornering forces and gravity from the cg pass through the contact patch. Therefore the oil will still tend to drain to the 'bottom' of the sump. In a car the driver can not lean the car to align the acceleration vector with the downwards local axis of the car so if he is cornering at 1g then the oil will tend to gather in the outside lower corner of the sump. If it is an F1 car the oil will mostly drain sideways out of the engine at some points, not downwards.

It isn't as cut and dried as this due to dynamic effects and longitudinal acceleration, but I think it is fair to say that for a given installation (and certainly if you install a horizontal bike engine vertically into a car) that a high performance car that is cornering a lot is the more difficult case. On the other other hand I expect road bike engines are designed expecting more fun and games than production car engines, so it may be a wash for production engines.

As marcush points out, actually designing the lube system is not done just on a computer, there is a fair amount of physical testing (hooray).

[xpensive]

....
With a bike the rider essentially leans the bike so the resultant vector of the cornering forces and gravity from the cg pass through the contact patch. Therefore the oil will still tend to drain to the 'bottom' of the sump.
...

That might be correct if the driver + bike's CoG-vector is in line with the bike's, but as can clearly be seen in the above image, that is not the case as the driver is leaning to the side, offsetting the total CoG, why the oil will be forced to the side anyway.

[riff_raff]

It is quite possible to overcome the oil scavenge problems created by installing an I4 engine longitudinally and "laid down". However, the more difficult problems are how do you route a suitable intake or exhaust manifold on the bottom side of the cylinder head with a "laid down" engine, and what do you do about the huge lateral engine CG offset resulting from keeping the crank CL at the chassis CL?

[Greg Locock]

Maybe lay it down enough that the things is almost on its side but with enough clearance for an exhaust manifold?

Why does the crank C/L have to be on the car C/L, necessarily? If necessary you could use rzeppas and run almost any silly prop shaft angle in plan view you wanted.

I think we lost the OP a while back.

yes, xpensive, the rider shifting his cg relative to the bike does increase the lateral (bike coordinate system) g, but it is still relatively small compared with that seen even in a road car.

[andylaurence]

If you transplant a bike engine into a car without attending to its oil demands, you'll be seeing plumes of smoke when you use high revs in a corner. They don't tend to take lateral G well. People vary in their approaches. I know a few people running a rotating oil pickup in a wet sump that rotates forwards under braking, backwards under acceleration, etc. That's normally combined with a baffle plate. Some people also add in an Accusump. The full-house option is a dry sump kit and that's what I've got fitted. I've got a tank of about 10-12cm diameter and 40-50cm tall. No oil surge at all at 1.8G. Hopefully, I can say "no surge at 2G" next year...

[riff_raff]

....Why does the crank C/L have to be on the car C/L, necessarily? If necessary you could use rzeppas and run almost any silly prop shaft angle in plan view you wanted.

I think we lost the OP a while back.....

It's not mandatory that the engine CL be located on the chassis CL (unless required by the rules), but it sure makes things easier. Virtually every race transaxle that I have ever seen has the input shaft located at the lateral center plane. So if you want to design your mid-engine race car with the crank CL laterally offset from the chassis CL by a significant amount, then you'll probably need to build a custom gearbox. As this picture shows, it is indeed possible to install an I4 engine laid down with the crank CL offset from the chassis CL: