Please explain "Integrated Dry Sump" oiling in M96.03 engine

[UCrazyKid]

So I keep hearing that the 996 M96.03 engine (Standard Carrera) doesnt have a "real" dry sump system. That only the Turbo, GT2, GT3 have this. How is the M96.03 different? Is this a real dissadvantage? How does it compare to the 993? What was the purpose behind this? Cheaper manufacturing?

Thanks,

Andy

[geza]

The original concept of a dry sump is that oil is scavenged out of the traditional sump and pumped into a separate tank where it could be stored, and also be less subject to oil surge when cornering at high speeds. This insures oil supply to the engine when all the pumps are working correctly.

If one is an optimist:

Porsche integrated the oil tank as part of the traditional sump concept for the 996 engines. The other engines you mentioned have a specific remote oil tank. The 996 block/case was designed for space and weight savings. The inclusion of the oil tank in the engine casings removed the need for external lines and enables a more compact design. There are baffle plates in this sump that prevent the oil from spilling into the areas where moving parts can be affected by this surge. So it is part of the engine as we would normally regard a sump, but with functional modifications that afford it a dry sump classification. People will say that some oil starvation problems are evident when these engines are tracked, and Porsche offers a modified baffle system to cater for this.

If one is a pessimist:

A dry sump means a dry sump - since the traditional sump is located under the crankshaft - so anything other than that means pseudo dry sump/wet sump with baffles.

The V bottom design of the Turbo/GT2/GT3 engine cases does not allow enough room/capacity for oil to be stored there - hence the need for a oil tank mounted between the engine and the rear bulkhead - plus these engines were derived from racing designs, and they are also much more expensive to manufacture.

[clord]

Hi Andy.... Yes, the motors in the 996, 986, 997, 987 (not Turbo, GT2, GT3) are very different from all previous 911 motors. They are a totally new design focusing on manufacturing economies. They are all advertised as having an "integrated dry sump". Many of us call them the "flat bottomed" motors since the bottom (sump area) is largely flat. The "old", traditional 911 motors have a somewhat cylindrical crankcase around the crankshaft, and counter/auxilliary shaft. The counter shaft is below and parallel to the crank and drives the cam chains and oil pump. The oil pump scavenges oil that falls to the crankcase floor and pumps it out of the crankcase to an external oil tank. The same pump also supplies the engine with oil from that tank which becomes a deep, reliable supply of oil in high G turns. This scheme enables a lower, more compact engine (no oil "pan" below the crank)....and enables the storage of a larger oil supply (in the external tank). This is the engine that Porsche designed for the first 911 and developed and developed and went racing with over the years to this day, in turbo charged form and NA form. In the 935 they began to experiment with water cooled heads (necessary to cool the valve area enough to enable 4 valve heads later). In the 1998's GT1 Racer, they went all water cooled, but, on the same basic dry sumped design. Today's Turbos, GT2, GT3 motors are derivations of that 40 year old dry sump design, but, with full water cooling, 4 valves/cyl, and variable valve timing. In the '90s, porsche designed a totally new flat 6 for the then new 996 and 986 emphasizing manufacturing efficiencies. The new motor has the cylinders cast in unit with the case halves, and a new steel two piece cradle around the crankshaft.....and the "integrated dry sump". The integrated dry sump is really just a familiar oil pan below the crank and counter shafts, but, separated from them (except in the middle where there's a hole) by horizontal casting. The oil pump sucks out of the pan and supplies the engine directly from there....there is no external tank. This simplifies the plumbing and construction. But the oil is still stored by gravity under the crank and countershafts. The scheme does do a better job of retaining the oil under the pump pickup than it would without the dividing casting, but, the first 3.4 liter versions did have some pick up problems in high G situation and did allow pooling of oil in the heads....and potential oil starvation in those high G turns. That was fixed in the 3.6s with baffling and another oil scavenge pump in the head area. The fact that the factory still goes racing with the "old", dry sump design and puts it in the Turbos, demonstrates that that "old" design has a plenty of extra strength designed into it.

[UCrazyKid]

Craig,

Thank you for the very detailed description of how the engines are designed. It answers all my questions.

Andy

[racerx]

The original concept of a dry sump is that oil is scavenged out of the traditional sump and pumped into a separate tank where it could be stored, and also be less subject to oil surge when cornering at high speeds. This insures oil supply to the engine when all the pumps are working correctly.

If one is an optimist:

Porsche integrated the oil tank as part of the traditional sump concept for the 996 engines. The other engines you mentioned have a specific remote oil tank. The 996 block/case was designed for space and weight savings. The inclusion of the oil tank in the engine casings removed the need for external lines and enables a more compact design. There are baffle plates in this sump that prevent the oil from spilling into the areas where moving parts can be affected by this surge. So it is part of the engine as we would normally regard a sump, but with functional modifications that afford it a dry sump classification. People will say that some oil starvation problems are evident when these engines are tracked, and Porsche offers a modified baffle system to cater for this.

If one is a pessimist:

A dry sump means a dry sump - since the traditional sump is located under the crankshaft - so anything other than that means pseudo dry sump/wet sump with baffles.

The V bottom design of the Turbo/GT2/GT3 engine cases does not allow enough room/capacity for oil to be stored there - hence the need for a oil tank mounted between the engine and the rear bulkhead - plus these engines were derived from racing designs, and they are also much more expensive to manufacture.

Geza,

You mention Porsche has a modified baffle system to cater to potential oil starvation problems. Is there a specific part you are referring to? I have seen Brey-Krause (sp?) offers a revised 'oil pan' but was unfamiliar with the Porsche part.

TIA

[ArneeA]

The original concept of a dry sump is that oil is scavenged out of the traditional sump and pumped into a separate tank where it could be stored, and also be less subject to oil surge when cornering at high speeds. This insures oil supply to the engine when all the pumps are working correctly.

If one is an optimist:

Porsche integrated the oil tank as part of the traditional sump concept for the 996 engines. The other engines you mentioned have a specific remote oil tank. The 996 block/case was designed for space and weight savings. The inclusion of the oil tank in the engine casings removed the need for external lines and enables a more compact design. There are baffle plates in this sump that prevent the oil from spilling into the areas where moving parts can be affected by this surge. So it is part of the engine as we would normally regard a sump, but with functional modifications that afford it a dry sump classification. People will say that some oil starvation problems are evident when these engines are tracked, and Porsche offers a modified baffle system to cater for this.

If one is a pessimist:

A dry sump means a dry sump - since the traditional sump is located under the crankshaft - so anything other than that means pseudo dry sump/wet sump with baffles.

The V bottom design of the Turbo/GT2/GT3 engine cases does not allow enough room/capacity for oil to be stored there - hence the need for a oil tank mounted between the engine and the rear bulkhead - plus these engines were derived from racing designs, and they are also much more expensive to manufacture.

Geza,

You mention Porsche has a modified baffle system to cater to potential oil starvation problems. Is there a specific part you are referring to? I have seen Brey-Krause (sp?) offers a revised 'oil pan' but was unfamiliar with the Porsche part.

TIA

He might be referring to this:

http://e-partssales.com/Merchant2/merchant...y_Code=996sport

[Loren]

The Porsche part is a part of the X51 kit.

Alone it may help some but the X51 get another oil pickup, dual-chamber suction pump, and separate routing of the oil return lines.

But then an X51 kit is about $10,000 plus installation cost.

[skyline]

So is this why when you do not use the car for a while all the oil runs back to the sump & weeps from the R.M.S.

[Costa]

No ! - The oil level when the engine is sitting still is way below the RMS seal level/lip etc, so no oil can escape even if the seal was removed.

Oil will only reach the seal while the engine is running.

If the seal is leaking - what will happen is that the oil will be spread around the seal area when the engine is running and once stopped, it will pool on the outside of the seal and drip down (if the leak is large enough).