Normal oil pressure ? See video. NOT MY CAR

[heliolps2]

Interesting Video, I just watched this video of a 965 3.6 for sale and towards the end of the video 8:48, the oil pressure seems really low, at idle it's below 1 bar, at 1000 rpm's Yikes. That can't be normal? My 965 drops to 1.9 - 2 bar at idle when really really hot in stop-and-go traffic with the AC on and the rpm's at 750-800 because the AC is on of course. That was my case when we had the heatwave here in DC recently. (For our NA 964 friends. The 965 doesn't have the idle valve that kicks up the rpm's when the AC is on)

At normal driving temperature with the AC off, my oil pressure sits closer to 2.5 - 3 bar but with AC on the pressure drops to 2 - 2.5 bar and goes to 4.5 to 5 bar fairly easy as the rpm's go up, Hot or at normal driving temps. What's normal? Please share.

Here's the link to the video, go to 8:48 on the video to see what I'm talking about. NOT MY CAR!
https://youtu.be/n0ivQ8k03tw

[heliolps2]

https://rennlist.com/forums/911-foru...ne-this-2.html

here's my attempt at a cut and paste of the article "" Start Quote

Tech Talk 911 Camshaft Oiling Update
By Steve Grosekemper, San Diego Region
(from THE WINDBLOWN WITNESS)
One of the benefits of writing a monthly article
like this is the great input I get from readers.
From time to time, they will send me interesting
technical bulletins or articles to evaluate.
One such article was written by Lee Rice, appearing
in last September’s Pandemonium, the
Orange Coast Region newsletter.

The article discussed the existence of an updated
cam oil line fitting for the cam housing on
pre-3.6L 911 engines. It restricts oil flow to the
camshafts by nearly 50%. I thought the article
was quite interesting, but I still had some questions
that Lee’s article did not answer. I decided
to go straight to the source and exchanged
several e-mails with Lee to get all the facts.
After several conversations and some additional
investigations by both of us, here is what we
came up with.

911 engines from late 1966 all the way to the
last 1989 3.2L Carreras and 1990 3.3L Turbos
use the same adapter piece connecting
the cam oil line to the camshaft housing (part
#901.105.361.00) (figure 1).

Starting with the 1991 911 Turbo, this adapter
was replaced with a new updated part with a
reduced center orifice. Porsche has not given
much information as to the reason for the update,
other than it reduces oil foaming. The new
adapter (part #901.105.361.01) is differentiated
from the older adapter by a groove around the
center when installed on an engine. Figure 2
shows the original adapter with a 6mm orifice
and the new one with a 2.5mm orifice.
Oil foaming is caused when there is too much
oil in the crankcase and it gets “whipped up” by
the rapidly rotating internal parts. You might be
wondering (much like I did) if such a large reduction
in orifice size would still deliver enough
oil to the cam housings. To find out, I installed
these adapters on several cars with greatly varied
oiling needs and scenarios.

One of the weakest oiling systems I installed the
adapters on was a 1975 911S. This was a high
mileage car that had no front oil cooler, a small
early style oil pump, and was still running the
original 5-blade cooling fan. The thermal reactors
were still in place. As you can imagine, it did not
take long to see 220-230 degrees of oil temperature
and no idle oil pressure. I figured that if the
updated fitting worked in this car, it would work
in anything.

After installing the adapters, I pulled the top
valve covers and had someone start the engine.
Oil vigorously sprayed from all of the holes in the
camshaft spray bar, which told me there was no
need to worry about low oil volume to the cam
housing. The surprise bonus was that the car now
showed about 10 psi on the oil pressure gauge
instead of a bright red warning light. All this for
two $5.10 fittings!

The next test was on my 914-6 racecar, which
has an interesting camshaft/cam housing setup.
The cam housings are later ‘74s with a central oil
spray bar. The camshafts, however, are ’66 911
cams with internal oiling (oil pressure from the
cam journal exits holes at the heel of the cam).
25 February 2010

Porsche used one or the other, but never both
types of oiling in the same engine due to the
inevitable loss of oil pressure at idle. I installed
the updated fittings and ran the same valve cover
test. This time I was amazed to witness what could
only be described as a very messy geyser of oil
coming from the right side cam housing. With
210-degree oil temperature, the oil pressure was
almost 30psi due to the engine’s turbo oil pump.
Pressure with the old fittings was closer to 10 psi.
After all our tests, we came up with the following
conclusions:
• The fittings decrease the oil to the cam housings
and decrease oil foaming.
• The decreased foaming allows the scavenge oil
pump to transfer oil out of the case and into the
storage tank much faster. This in turn keeps the
oil tank level more consistent and causes the oil
level gauge to react quicker.
• Less oil foaming will lead to less consumption
of oil through the engine breather system.
• The smaller orifice creates higher oil pressure
at the main and rod bearings as well as at the
piston squirters. We noticed a 10-20 psi increase
in oil pressure. Nothing to sneeze at.
All in all, these fittings seem to be a great addition
to any early 911 engine. With an extremely
low cost and huge lubrication benefit, I am sure
that even the most frugal 911 owner will be eager
to spend a little and gain a lot in performing this
update.

End quote ""

[heliolps2]

Quote from Grandy Clay

What happened to the poster who suggested we consult some “Real” engine builders? I oversaw more than 1000 911 engine builds. Some very radical for their day. Ask Pelican rs911t who still drives a 2.8S built in ’74.

In the past week, I poled 14 builders nationwide that I consider the “best experts” (certainly not even close to all). Without exception, all agreed with my assertion.

There was brought up an additional indication supporting my contention.

Porsche changed the low oil pressure warning light switch from 0.5-0.7 bar to 0.3-0.5 bar. Their contention is that was also for ‘political’ reasons – customers were complaining to Dealers that the oil light was “flickering” at idle when hot.

While it is understandable that our Beloved Manufacturer would do these things for “customer relations” reasons, we shouldn’t overlook all the technical issues.

We have the benefit of hindsight that the Factory engineers didn’t when engineering and built our 911s. We can build a ’65, ’73, ’83, ’89 engine better today than the original. Some of that is because we are not in a manufacturing environment. In many cases (track cars) we don’t have to follow ANY regulations. Mostly we have the benefit of hindsight. We have the choice to add more oil circulation (or less). We can choose the oil pressure our engines run (1.0 to 200 psi), independent of what anyone says (not that we would choose either extreme). The point is we can build a better engine today than Porsche did originally – no fault of theirs.


SO, - - -
Let me re-state my postulate:
More oil to the cam housing is better than less. The main oil pressure needs to stay above the point where the pistons squirters open. Excess crankcase scavenging (and other tricks) that reduce the crankcase pressure are to the benefit of power.


How do we do this?

Certainly not by restricting oil flow to the cams.

The proper way is with the largest possible oil pump. Today that seems to be the 3-section GT3 pump. A close second is the (more expensive) Turbo pump. Either can be fitted to every 911 engine from ’65 (with slight mod).

I haven’t surveyed the availability of current cam profiles with center-oiling. I suspect that this is an easy mod (Porsche did it with SCRS). This allows both center-oiling and spray-bar oiling.


Please let’s have some other info. I don’t have a problem with contrary views. In fact, I welcome them. That is how [b]I[/i] learn.

Best,
Grady

[heliolps2]

I also fund this post.

Sorry to be confusing.

I am not advocating relocating the pressure transmitter, I am only asking you to think through what happens vs what you see on the gauge.

As you note the oil pump is a Positive displacement (PD) style. This means that for each rotation of the shaft, approximately the same volume of oil is moved.

The discharge pressure from the pump (what we see in the oil pressure gauge) is created by the downstream line losses. In the case of a Porsche Engine, the oil goes through the engine internal passages to the lower crankshaft Galleys, the piston squirters, and the heads before it goes to the sump to be cooled, filtered, and returned to the oil tank for its next lap.

The pressure transmitter is usually located near the passages supplying the piston squirters and upstream of the Cam tower oil lines.

The restrictor, which is downstream of the oil pressure transmitter, creates an additional restriction of oil flow to the heads. since the pump puts out the same amount of flow, more flow goes to the piston squirters/crankshaft galleys and less to the heads.

Since the restrictor is adding pressure drop to the entire oiling system, and the flow is constant, the oil pump output pressure increases to maintain the fixed flow rate. This is why you see the higher pressure at the gauge. I was only asking if you would feel the same way if the transmitter was on the other side of the restrictions so that when you installed them the pressure will appear to go down.

I do not see this as a good thing (to my engineer mind). This means less oil to the heads in exchange for more oil to the piston squirters and crankshaft galley. Normally I would say this is a good thing but since the hottest area in a Porsche engine is the heads and the flowing oil provides the cooling, I am thinking this is not a good thing.

One more factoid to consider is that when Porsche went to the restrictors, they also increased the total flow from the oil pump. As a result, they kept the SAME flow to the heads and INCREASED the flow to the piston squirters and crankshaft.

Also, there are many posts on this topic (as I am sure you already know). As I recollect, Grady Clay posted that how Porsche engineers choose to allocate the oil flow was a bit of a compromise and part of the addition of the restrictors were to get the piston squirters to operate at a lower rpm.

I hope this long-winded explanation helps.

[heliolps2]

I reached out to Chris at Turbo Kraft and this was his reply

Hi Helio,

What an awful video -- when non-Porsche guys sell cars: "check out this gas cap..." Ugh. And anything sold in Miami is not to be trusted but inspected by an independent specialist.
Yes, that's less oil pressure than it would normally have at idle. The 3.6T had the larger 2mm piston oil squirters and the big Turbo oil pump, and all-stock they make 1.5-2.0bar at idle. But frankly, Porsche doesn't much care how much oil pressure your engine makes at idle; their specification (from top of my head) is 4bar at 5,000rpm, and as long as the low oil pressure warning light doesn't come on at idle then you're usually fine.
We've built a few engines that have oil pressure like that, but they trade pressure for volume because they make in excess of 700hp.
There are cam oiling no restrictors on the 964-based engines, they use an "oil bridge" between the cam housing and chain housing.
We think the restrictors are a terrible idea and remove them. Again, we'd rather have more volume than pressure, especially for cam/rocker lubrication.
And no Mobil-1 oil.

- Chris Carroll
TurboKraft Inc.

[heliolps2]

I would be inclined to drill out the restrictors from 2.5mm to 4mm, to be somewhere in the middle. Without the restrictor, it's 6mm. I understand why the engineering team at Porsche did it. It seems to a compromise for the bottom end and the top end oil pressure. I'm sure your read what I posted from other forums members and engine builders. it's a highly debated conversation. But I will lean more toward the engineers at Porsche. When Porsche went to the restrictors they also increased the total flow from the oil pump. As a result, they kept the same flow to the heads and increased the flow to the piston squirters and crankshaft. I not an engineer but it seems to make sense to me. I may drill out the restrictor to 4mm in the future. I have 58k on my car and the cams looked great when I had the engine out over the winter. In a hotter climate I'm it would be different.

https://rennlist.com/forums/964-turbo-forum/1257643-normal-oil-pressure-see-video-not-my-car.html

Helio