new updated cam tower fitting

[lagoon]

Has anybody seen the updated cam housing fitting that is smaller in diameter? This was an update for the 964 but applies to 66-89 engines. Looks like a good improvement on oil pressure. p/n 901.105.361.01 Benefits are less oil foaming,higher oil pressure at the main & rod bearing & piston squirters. Anybody? 81'SC

[Doug Zielke]

Glad you brought this up, lagoon.
The first I heard of this, was just recently as I read Waynes new book. He mentions it in the "modifications and upgrades" section.
I ordered the parts immediately. There is a Porsche technical bulletin outlining the change. Seems to be a fairly large benefit, for a small cost.

[ttweed]

My mechanic wrote a tech article on this update for the local PCA newsletter back in Mar. It's at http://www.dietersmotorsports.com/tech/2002/3-2002.htm
Bruce Anderson picked up on it and mentioned it and him in his Excellence column a few months later.

[lagoon]

Doug, I am ordering the fittings next day. Will see what happens to my oil pressure.. 81'SC

[Wayne 962]

I attibuted the find to Steve Grosekemper (your mechanic) in the book! You might want to pass that on, next time you see him...

-Wayne

[Vipergrün]

Wayne, per your site, is PN A-105-361-01 the correct one for these updated parts?

Also, perhaps a lame question, but is there a key somewhere to figure out what your alpha part number prefixes represent? In other words, does the 'A' in the above PN correllate to '901'?

The actual part for this fix is 901.105.361.01.

Thanks much.

[911pcars]

I might add that this modification was illustrated and described a few months ago by our own Bruce Hermann (Gibson) who didn't have the patience to wait in the mail and instead made up his own parts. Yup. Increased oil pressure was the end result. PParts has the parts - about $4-$5 ea.

Cam oil line fittings finally in!

Make sure you get the correct size aluminum sealing washers for the fitting and the banjo fitting that screws on top of it (total of 3 washers/side).

Sherwood Lee
http://members.rennlist.org/911pcars

[ttweed]

Originally posted by Wayne at Pelican Parts
I attibuted the find to Steve Grosekemper (your mechanic) in the book! You might want to pass that on, next time you see him...

I will, Wayne, but in his article, Steve attributes the original initiative and legwork to Lee Rice (in the September 2001 issue of Pandemonium, the Orange County Region newsletter). All he did was collaborate on the followup investigation and testing to determine the results on several different motors.

[jmohn]

Are these fittings and washers available through Pelican? And, just how "necessary" is this "update"? I've been following the discussion on this, both here (911 BBS) and through Rennlist, and I've yet to determine how valuable this fitting change is. My car ('78SC) has about 100K miles on it, I'm using 15-40 dino oil, I show 5 bar oil pressure at 5000 RPM and about 3.5 bar at 3000 RPM, oil use is minimal (about 1 qt. per 3000 miles). I'm loath to change these fittings on an engine that's appears to be funtioning quite well unless there is some benefit beyond raising oil pressure (which, I think, is quite good in my car).

Jerry M
'78 SC

[RoninLB]

Originally posted by jmohn
I'm loath to change these fittings on an engine that's appears to be funtioning quite well unless there is some benefit beyond raising oil pressure (which, I think, is quite good in my car).

Jerry M
'78 SC

I'm w/Jerry on this one.. maybe in a few years there will be big follow up discussions.. I'll wait this up-grade out.........Ron

[911pcars]

Quote from the article:
"After all our tests, we came up with the following conclusions:
- The new fittings decrease 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. The increase we noticed varied from 10-20 psi. "

There appears to be other improvements in addition to increased oil pressure. Engines with hydraulic chain tensioners seem to lose some oil pressure due to this added circuitry, and these adapters may help restore the lost pressure.

Sherwood Lee
http://members.rennlist.org/911pcars

[GIBSON]

As Sherwood mentioned, I did update my 73S motor with these cam plugs. I did it first by making my own, which had a slightly larger lumen than the factory parts and then installed the factory pieces. Yes, I did notice a difference in oil pressure across the board.
I removed the enigne at 1000 mi and did a service. I noticed that the #3 and to a lesser extent the #6 exhaust ports were wet with oil. I attributed some of this oil to the fact that the engine was sitting at an exaggerated angle for some time before I took the engine out (doing body work). The #3 port was the low point of the engine during this time prior to removing the engine. Leakdowns were fine, it smoked a small amount and I assumed the rings were not fully seated and allowed the oil to seep by. BTW, I installed the engine and have noted little smoke since and no unusual oil usage.
Anyway, I wondered if using the reducer fittings in the cam lines could have produce more oil sprayed onto the piston/barrels and the cam spray bar, affecting the seating of the rings. Bruce Anderson said he thought this would not contribute to any ring seating problems. I'm not sure but to be safe I removed the fittings and went back to the stock ones. I'm not really sure if that was necessary and I may re-install them when I'm sure the rings are fully seated. We'll see. I noticed the drop in oil pressure without the fittings.
One other note, I think the main problem with the rings not fully seating is the driver. I think the engine needs more aggressive driving than I offered it during the first 1K miles. I varied the rpm etc. but I'm now getting the revs up and pushing it harder. Seems to be working.

[jmohn]

Originally posted by 911pcars
Quote from the article:
"After all our tests, we came up with the following conclusions:
- The new fittings decrease 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. The increase we noticed varied from 10-20 psi. "

There appears to be other improvements in addition to increased oil pressure. Engines with hydraulic chain tensioners seem to lose some oil pressure due to this added circuitry, and these adapters may help restore the lost pressure.

Sherwood Lee
http://members.rennlist.org/911pcars

Precisely. I'm aware of the other "improvements", as I said, I have followed this thread. I accept this is a "desirable" upgrade, especially on an engine with less than optimal pressure and/or subject to extended high RPM (which, I presume, would contribute to foaming); but is it "necessary" on an engine with excellent oil pressure, minimal oil use, not subject to extended high RPM use? As to the oil level sender, I never believe it anyway (that's what the dip-stick is for). Now, creating higher pressures at the main & rod bearings and squirters is certainly a benefit, but I though if the engine has adequate pressure showing on the gauge, it has that pressure throughout the engine. So the question is: with the stock fitting and excellent oil pressure showing on the gauge (i.e. 5 bar @ 5K RPM), are the main & rod bearings and squirters receiving less than adequate oil pressure? If the answer is "yes", then I'll be upgrading as soon as possible, but I have yet to find this information in any of the threads I've read. I accept that pressure will be "improved", but is it "necessary" on all engines regardless of condition and conditions of use?

Jerry M
'78 SC

[Wayne 962]

I attributed the find to both of them in the book. A- does correspond to 901, but I wouldn't say that's a hard and fast rule. Porsche does not let us list their OEM part numbers on the site...

-Wayne

[armandodiaz]

Are these restrictors recommended for high milage engines? I'm fearing of installing these restrictors, increasing the pressure and then having oil leaking problems. My engine has over 150K miles and as it is, I'm constantly chasing oil leaks.

[chuckw951]

Here is a picture to illustrate the difference between the stock and updated fitting.

[fredmeister]

I have been running them on my 79 911SC since roughly 8000 miles now and the engine has 150k miles on it. I DE the car once per month and noticed an increase in oil pressure by about 10psi max across the board. No noticeable change in oil consumption and no problems with the engine smoking, leaking or otherwise. Seems to have made no difference negatively, but I have not torn down camshafts to check for wear. At valve adjustment time everything on the camlobes looks good so far. I say try them, if Porsche designed it then it should be fine.
Anyone done an analysis on wear patterns after extended useage?