Mike Murphy

It does seem odd, but that system is having a tough time keeping the idle smooth, and that’s its purpose.

Going back to what Porschetech3 said, I think you need to have someone take a look at your car, pull codes, take some measurements, etc. Seems like there are too many variable items at play.

Ben8jam

No I think it's mostly when coasting through turns, if I'm high rev pushing through a turn, there is no way I can pay attention to the pressure gauge.

As said, I'll do a full canyon run and report back (maybe video the gauges or at least make mental notes of "pushing" "coasting" pressure etc) -- especially as pertains to just simply adding more oil seems to settle things....

I'm still shocked two people's covers were backwards and only found out b/c of this thread.

And yes to getting all the more detailed specs/readings...

Porschetech3

It doesn't shock me, after about 50 years professionally in this bussenes , it takes a LOT to shock me...

This makes about 5 of these cases of incorrectly installed scavenge pumps I have discovered in the last 6 months..People send me private questions about my upgraded products, and are asking questions and sometimes tell me about their problems they are experiencing...The last thing I want to do is sell them a product that doesn't cure thier problem, so when I suspect something else is going on, I tell them to do some testing/checking and this has came to the case several times...It is getting more prevalent...

The upgraded products are to "enhance " the performance of the 996 above the factory design, not to fix a problem of a degraded system.... but it can do BOTH in some cases when the root cause is actually "pinpointed " to be the causal part..and the upgraded part is the same part that had degraded below specs//

Unfortunately sometimes the incorrectly installed scavenge pump is found on a forensic analysis "post mortem" as is the case of a former active Rennlister that contacted me about his catastrophic failure after a recent repair to the vario cam pads...

996love

Okay, glad to hear about the thermostat.

Unless you’re averaging 60mph+ on your canyon runs, you’re not getting optimum air flow through your radiators. (I read it here, on rennlist).

I’d recommend adding a switch to activate your radiator fans. I think it ought to help to lower coolant temps, as well as oil temps, and therefore improving hot oil pressure. If it doesn’t, and you don’t like it, just remove it later.

Also, have you tried clearing any debris from your radiators?

Ben8jam

Ehh well... not sure I should respond to that publicly...

996love

Haha, I suppose the fan mod won’t be necessary, then!

Ben8jam

Update: Not a perfect test as half the drive up was covered in super thick fog, but once got to top of first climb, broke through to sun. Tried to drive and film my dash one handed, so was being a lot more careful, and i can say the flux in oil pressure in turns is very much there, but it stays around the 2 in the worst of them. It happens on both directions, but seemingly much more on right hand turns. Accelerating in the turn keeps the pressure higher.

Temps go up to the 0 in 180, but never past it. Even with the last half of the drive where I put the phone down and kept it high rev.

I got to the end point, and came to stop, and I did see the oil pressure light come on for a brief second then go off. I then drove another half mile and stopped again, and this time light came on. Pressure indicator at .25.

But a little tap of gas and it went away. From that point it was all back down hill so temps dropped and no issues.

I still need a warm day to properly test, but it seems adding that extra oil has smoothed a lot of the issues, does that make sense? But NOW what about these swaying pressures? It's all gotta be related somehow. It's hard to draw a conclusion, the indicator just kind goes smoothly up and down throughout different maneuvers.

And yes, I need all the extra more detailed tools to test, but I'm working with the limited time I have available right now

Peppaporsche

Combined the removal/reseal/install of the pax side (LHD) scavenge pump with a bunch of other projects with her feet off the ground. After clocking the pump properly, I can confirm that the oil pressure is at least .5bar higher throughout the rpm range for normal operating temperature. Additionally, there is minimal to no drop in oil pressure associated with lateral G’s! From looking at the pump while removed I can see that you are definitely reducing the port size for pick up by having it misclocked, and as has been already mentioned you would be in serious trouble if the pump was installed at either of the 90’s.

sublm8

Drop the sump. You need a visual on the pick up tube and baffles.
Check your oil pressure relief spring too.

wdb

That sounds like something a 5W-50 oil might help with.

allcool

Like I already said 1-2 bar op is not enough when hard cornering at anything over an idle speed rpm. You need 1 bar per 1000rpm. 4bar @ 4000rpm minimum is what m996 experts recommend. And thats not intermittently thru a corner, thats a continuous steady pressure reading that does not drop. When it drops even a little, some bearing is getting starved from its film of protective oil. I'd rather see a continuous slightly lower full time pressure, than a sudden drop/fluctuation. This type op drop causes a cumulative type damage that compounds the problem by wearing more and more on bearings making them less able to hold their protective oil film and keep up oil pressure. What I'm saying is, every incident of op drop at speed/especially under load, all adds up till eventually....

When your op goes from 4 bar to 2 bar in a hard corner without a big rpm change, you are oil starving main/rod/all/ bearings. This will take its toll eventually maybe with a catastrophic ending.

Don't drive your car so it goes to lower oil pressure in corners or be ready for the wor$t...

Ben8jam

Well sadly, I finally got some time to get the car out, and did the run up the crest on a now warm day. Temps held steady to top at right side of 0 in 180, but when I came to stop the oil dropped to .5, the light came on, and the tick is back. It ticks even with some gas in neutral till pressure goes up then it stops.

Pressure in turns continues to flux greatly in either direction. The drops occur right at the turn entry and start to stabalize in the turn, then go back up as existing the turn. So confusing....

The only difference is I replaced the oil sensor spring and gasket last week, and in process maybe left out an 1/8th cup of oil. So it's possible that tiny extra oil was doing something.... The internal sensor shows near full with top two bars missing, and stick shows 3/4 - after many days sitting.

I've got the loctite, so when I'm back next week will drop the sump.

(Yes AllCool, I know you said not to drive it, but i gotta start making some attempts at fixing it before handing it over to mechanic who likely will start poking in dark too)

Peppaporsche

Didn’t scroll through all your posts, but my car was exhibiting the same problem with lateral G oil pressure fluctuations and I found that the scavenge pump on one bank had been put in 180 out when a local shop replaced the vario cam.

Mike Murphy

I would stop doing all these canyon runs and start systematically checking items, such as dropping the sump (unless that was already done)?

If you keep running the engine this way you might be starving your engine of precious oil - and doing irreversible damage.

Skip said to put a real pressure gauge on the engine - were you able to do that?

Did you check the orientation of the scavenge pumps?

Ben8jam

Yes checked the both scavenger pumps. They are in correct orientation. No, I haven't added an oil pressure gauge into the system. I'm terribly busy and haven't had a chance to look into what that would take to even do that. I was hoping to try single elimination tests at first.

Sump is next. The loctite arrived.

I'm not killing it in the canyons with super high revs it's just a "safe" place to get some high Gs, which is the only thing that causes the pressure to sway. AND going up the canyon gets the engine at it's highest heat level to diagonise the high heat low pressure. That's all.