Oil pump question for Wayne

[126coupe]

Im building a highly strung 2.5 L racing engine. I bought a race prepared case from Ollies. i have new Mahle 2.5 P and Cyl.
The case has been prepared to accept a later 964 pump. I already had purchased a Carrera pump. Is their an advantage to putting in a later 964 pump? does the later pump allow less oil in the crankcase? Thoughts??

[HawgRyder]

Minkoff....this is a turbo pump which is the same as a 964 pump I think.

[Ho Hum 74]

I don't think they are the same. I was told by Sol Sneideman at Perfect Power IL (Mentioned as a highly respected race engine builder in Bruce Anderson's book) that the Carrera pump is fine. The problem comes when braking. Today's tires can produce enough braking decceleration that the oil can move away from the pickup in your tank and reduce your oil pressure. Now under those conditions it doesn't matter if you have a massive pump if there is nothing to pump. The issue is with the oil tank: it needs baffles inserted to reduce this effect.

Tristan

[Wayne 962]

Yes, this is confusing, and there is even a typo in my Engine Rebuild Book on the subject, which lends more confusion.

- The 1976-83 oil pump has the same characteristics as the Carrera Oil pump with the built-in screen.

- The Turbo pump used from 1978-89 has a larger pressure side and a larger scavenge side. The larger pressure side is used to compensate for oil supplies sent to the turbo, and also for the larger piston squirters

- The 964 pump has the same pressure side and a larger scavenge side.

-Wayne

[Wayne 962]

Originally posted by Ho Hum 74
I don't think they are the same. I was told by Sol Sneideman at Perfect Power IL (Mentioned as a highly respected race engine builder in Bruce Anderson's book) that the Carrera pump is fine. The problem comes when braking. Today's tires can produce enough braking decceleration that the oil can move away from the pickup in your tank and reduce your oil pressure. Now under those conditions it doesn't matter if you have a massive pump if there is nothing to pump. The issue is with the oil tank: it needs baffles inserted to reduce this effect.

Tristan

Baffles do help, but in general, oil starvation on the track is not a problem that 911s are known for, unless you're running an autocross for hours at a time...

-Wayne

[Ho Hum 74]

Wayne,

Turns 5 and 11 (Canada corner) at Road America have been know to cause the oil pressure light to come on. Chris Streit (our local hero) had this happen and since his oil baffle mod was applied has had no worries.

Tristan

[armandodiaz]

Originally posted by Wayne at Pelican Parts
Baffles do help, but in general, oil starvation on the track is not a problem that 911s are known for, unless you're running an autocross for hours at a time...

-Wayne

So Wayne when rebuilding is it best to go with the 964 or the Turbo? Your book states Turbo but says nothing about the 964. I will be building a track only 3.2.

[Henry Schmidt]

The 964 and turbo pumps are not the same . The turbo has a larger pressure side (2.25" vs 2.0") and the turbo pump has a cast iron scavenge side. Both the turbo and the 964 pump have a 5" scavenge side. The Carrera pump is perfect for smaller engines. [ 2.0 to 3.0- 250 hp and less.]
As for the 964 pump, we use them but we have seen many cracked housings and because of that we only use turbo pumps when building big, high performance engines [3.2 and larger]

[Grady Clay]

Minkoff,

I have the Turbo pump in my three 2.5 (91x66) race engines. Worked great.
The reason for the more capacity is the cams are both
center oiled and spray bar, like 935s.
I’m looking to keep the heads cooler and the cams and 935 rockers to last.

Here it is with the early 930 pump (’75-‘77?)



I’ll second the admonition about the oil tanks needing baffles.
I extended my tank upward by about 3 quarts on my
SCCA GT-2 914-6 and ran the oil level high enough to puke
about one quart each track session.
I have a one gal. catch can with fuel cell foam.
I don’t think it dumps the oil until I get back to the paddock.
I tend to run the cool-off lap at 5-6000 to keep lots
of oil circulating and lots of engine air flow.

In spite of the precautions, I can still turn on the oil light
under extreme braking and very high revs (8300+).
I have a 2 bar (30 psi) adjustable oil pressure switch (a 917 part number).
When the engine is race hot, the light will come on full at 4000 RPM.
Since the engine is hardly ever below 6000, it isn’t a distraction.
I have a substantial red trailer light as an oil pressure idiot light.

Best,
Grady

[armandodiaz]

Thanks Henry, I'll take reliablity any day of the week.

[Steve@Rennsport]

I'll second Grady on using a Turbo pump or the even better (yet less $$$) GT-3R pump.

One needs lots of volume & pressure to make a race engine live as well as run cool as possible.

For engines that will be operated continously at 7800 or more, I'd also recommend cross-drilling the crank and opening the main gallery holes in the case and center main bearing.

[Grady Clay]

Steve,
Can you post some images?

I haven’t paid much attention recently. Are GT-3R/RS/RSR parts available from PCNA or only from Alvin?

Is the pump the same as a street GT-3?

What are the pumping dimensions of the pump?

Is there anything unusual to fit the pump?



Cool, you are practicing the Art of Porsche.

Best,
Grady

[Glenn Yee]

Call Ollie's since they did the work. They would know. They can port and polish either for better flow and pressure. A bypass has to be done so the case does not fill with oil when cold. There is additional machine work to put in a late style pump in an early case. You will know as soon as you try to put the pump in.

Excellent choice in machine shops. I've been using them for over 30 years and the service and attitude have always been exemplary.

Glenn Yee Motorsports, LLC

[Henry Schmidt]

Originally posted by Glenn Yee
Call Ollie's since they did the work. They would know. They can port and polish either for better flow and pressure. A bypass has to be done so the case does not fill with oil when cold. There is additional machine work to put in a late style pump in an early case. You will know as soon as you try to put the pump in.

Excellent choice in machine shops. I've been using them for over 30 years and the service and attitude have always been exemplary.

Glenn Yee Motorsports, LLC

Hey Glen, are you getting a kick back from Ollies ? We get that you like them, but opinions vary.
Bill @ E.M.S. 310-641-7019 and Walt @ Competition Engineering 760-379-3879 offer equal or better service and generally quicker turn around.

[ChrisBennet]

Henry,
I don't think you're being fair to Glenn. Glenn has only mentioned Ollies in 3 out his 4 posts to date. Sure he suggested that Tron send his heads all the way from Norway but I don't think is has anything to do with the free steak knives he'll get for all these customer referrals.
Just teasin' ya Glenn.
-Chris

[Wayne 962]

For reference, EMS, Ollies, and Competition Engineering are all very fine machine shops. I typically recommend EMS and Comp Eng, as I have personally dealt with them, and have not personally dealt with Ollies (although many people have, and only have good things to say)...

-Wayne

[cstreit]

Originally posted by Henry Schmidt
Bill @ E.M.S. 310-641-7019 and Walt @ Competition Engineering 760-379-3879 offer equal or better service and generally quicker turn around.

I know Comp Engineering does great work, but this is the first time I've ever heard them being 'accused' of quick turnaround. Perhaps they are always backlogged, but I also know it's worth the wait...