How are modern 911 motors designed?

[Wrecked944]

As we all know, in the air cooled world, the cylinders are like jugs attached to the crank case which is made of two separate pieces. Each cylinder gets its own head. But how are the modern 911's configured? Are there two cylinder banks cut from a solid block attached to a crank case? And is the crank case still made of two separate pieces?

I have heard that the GT3 uses the same crank case as my 964. Is this possible? And if so, how did they convert it for water cooled use?

[svandamme]

the gt3 doesn't hold water

[smcdermaid]

I am curious about this also. As I understand it, all of the 996 performance variants (GT2, GT3, RS, RSR & regular turbo) utilize the case from the 993 turbo-(direct relation to 964 version) and it's associated dry sump system. Do they have liquid cooled heads attached? Ala 956? Not debating the merits of this just interested in clarification.

[svandamme]

GT2 holds water

[OOH-911]

I thought the GT3 which is a 996 is a water pumper also. I am confused.

[svandamme]

eeh, so am i

apparently it's a pumper, just read some stuff
it's the dry sump thing that's on the GT3 but not on the normal 996

i assumed that the dry sump meant no water, but i was wrong on that, kinda messes up my attempt at dry humor too

[Superman]

Here's a TOTAL digression, but does anyone know why someone would name a boat "Thales?"

[Randy Webb]

Uh, what happened to the super-knowledge?

Thales wrote a book on navigation (supposedly). Little is known for sure about him -- he is said to have been the first philosopher (a broad category n ancient Greece) and an all-around righteous dude (if I'm translating Plato correctly).

[Bill Verburg]

The good 996 engines aka GT2, GT3, GT3Cup etc are built on the old 964 case but w/ different crank cylinders heads etc. The cyl and heads are water cooled. They are dry sumped

Here is a pic from the Porsche site showing the oil system


Here's a shot of the crankcase an lower cylinders

[KobaltBlau]

first picture...

looks like an oil/water heat exchanger in the middle. I was unable to find a similar picture for the normal 996 engines, though I tried. I think the 1/2 case and one set of cylinders are 1 piece, like a subaru.

second picture looks familiar.

[Beethoven]

Thales speculated that everything came from water. And "thalassa' in Greek means ocean.
But back to the question: what does dry sumped really mean?

[ChrisBennet]

"Dry sump" means that the oil reservoir is remote from the sump. The "sump" is the low point where the oil collects. Race cars, Ferraris and pre-996 911's have dry sumps with a remote oil tank.
A dry sump allows the motor to sit lower in the car and keeps high G forces from starving the oil pump.
EDIT: And it keeps oil drag off the crank.
-Chris

[jazzbass]

Originally posted by ChrisBennet
A dry sump allows the motor to sit lower in the car and keeps high G forces from starving the oil pump.
EDIT: And it keeps oil drag off the crank.
-Chris

And it keeps the oil from sloshing into the cylinder heads on flat, horizontally opposed engines. And makes you buy an entire case of oil for a single oil change. Unless you buy synthetics. Then you buy two cases of oil per oil change.

[briansc]

It also keeps the amount of 'Froth' in the oil to a minimum or at least manageable level. Therefor sending good steams of oil not air through the system.

[Beethoven]

Thanks!

[A Quiet Boom]

And, it produces more power in two ways, first it keeps more oil off the crank reducing drag and second in effectively pulls a vacuum on the crankcase helping ring seal. Just to add a few points to the benefit of a dry sump system.

[TerryH]

Originally posted by Superman
Here's a TOTAL digression, but does anyone know why someone would name a boat "Thales?"

Columbuth thaled the ocean blue in 14 hundred and 92.

So if one has a bit of a lisp it's... hoithst them thales, matey!

[Wrecked944]

Originally posted by Bill Verburg
The good 996 engines aka GT2, GT3, GT3Cup etc are built on the old 964 case but w/ different crank cylinders heads etc. The cyl and heads are water cooled. They are dry sumped

Aaaahh...so are the cylinders and cylinder heads still separate units or are they machined out of a single block?

[A Quiet Boom]

Originally posted by JanusCole
Aaaahh...so are the cylinders and cylinder heads still separate units or are they machined out of a single block?

Naw, they just cut them off old Chevy motors and weld 'em on!

Seriously guessing here but I'd bet the cylinders are merged as well as the heads, which poses and interesting question. Suppose those 4 valve cylinder heads could be reworked for use with aircooled cylinders ala 959? Add some TVM's and let the fun begin!

[Bill Verburg]

GT3 cylinder parts

GT3 head parts