cam oil line Restrictor/Adapter

[911 tweaks]

In the current(10/06) Panorama issue, the question is asked if one should use the "Restrictor/Adapter" in the cam oil line.
I have attached pictures of an 81' SC engines' such cam oil line attachmant points to the cam towers.

1. Can someone please verify, if possible, if the Restrictor/Adapter are present here OR if these are standard stand-offs? that allow the cam line to be attached.

2. If these are not the R/A, does the R/A replace these appearing to be stand-offs?

3. Is this a good update that Mr. Powell highly recommends?

Thanks Pelican Techies to the rescue again!!!

Bob

[eapcpa]

Don't see your picture but the oil line restrictors have a groove machined in the center of the outside hex surface. You can see these in wayne's book under upgrades, I believe. You can purchase these from our host for about $16 for the kit that includes the crush washers. This is a good upgrade for your engine.

[911 tweaks]

lets see if this works. I hope that Ed is linked to this post so he can verify his comments to be accurate or further comment. Thanks to Scott at Pelican for your tech computer help :-) here we try again...

[cstreit]

That's the old style, not the restrictor.

[911 tweaks]

thanks Chris!
1. Do you agree with doing this update?
2. Maybe I should poke a wire or something into the 3 holes on the spray bar while the valve covers are off just to make sure they are not plugged?
3. How do the update lines look...even though they are not completly shown in the pictures?
Thanks again everyone...Bob

[eapcpa]

Ditto, old style.

[911 tweaks]

I guess thats a wrap! Thanks everyone...any last comments i.e. should I be poking a pc of wire into the oil bar holes to make sure they are not plugged OR is this a no-no?

Bob

[MotoSook]

Why are you concerned about poking a wire into you cam oil bars?

The newer fitting/restrictor has a cut on the fitting (makes it look like two thin nut heads sistered together). Search the Techincal Forum. We have discussed this in length.

Steve Groskemper of the San Diego PCA wrote an article on it. That article is linked in the thread you will find in the Technical Forum.

I recommend the restrictor.

[911 tweaks]

thanks Souk. I will search fro the info. As far as poking the holes with a wire...it is kinda one of those things that since I can do it as the valve covers are off...am I asking for trouble in doint this? Any valve things in there or something that can be damaged?

You are way more qualified than me on these engines...basically is it ok to do or should I move on to betterthings? Thanks for your time.
Bob

[MotoSook]

Move on. The orifices on the spray bar are 2 millimeter or less, you're not going to conclude anything. Clean the area around the fitting before you remove it so you don't deposit anything in there while you are replacing the fitting.

[Henry Schmidt]

IMPO all 911 engine should be retrofitted with cam feed oil restricters.
The restriction reduces flow the the cam towers keeping more pressure in the lower end of the engine.
The old fittings flow close to 18 gallons per hour and the restricter flow close to 12 gal/hr.
This allows for a more than adequate flow to the cams and rockers yet not fill the engine with unnecessary oil that must be scavenged later.

These were standard equipment on 91 & later Turbos.
The flow restriction was built into all C2 (964>) engine after 89.

[Carrera3.5L]

Here's some images that may be of help:

A comparison of the two:









Ralph

[911 tweaks]

Thanks a lot Souk, Henry and Ralph!! Holly s&^t what a difference in dia of center hole that the oil travels through.
Any predictions/facts of how much the oil pressure increases at idle and wot?

WOW!! I am still blown away at that difference. I can imagine exactly what Henry was saying as the engine would be flooded with oil on top which would have to find its was down to the bottom of the engine to then be scavenged and sent out to the cooler...

I am being lazy with this add-on question, but, any suggestions on torque spec for fitting and should the threads be treated with anything??

Thanks again all!!
Bob

[Cupcar]

I have used these restrictors with the early pre '75 oil pump along with the 1980 SC oil pick up "venturi" and '75 pressure bypass modification.

My thought is that the decreased oil going into the crankcase from the top end and oil bypass along with the relatively larger scavenge side in the early pump working with the SC "venturi" to lower oil level and cut windage losses.

Whether this works as I think is open for discussion.

The idle oil pressure seems better with the restrictors and the early pump too.

[Mysterytrain]

Is it true that the banjo bolt was also changed and should be included in the 'upgrade'???

[MotoSook]

No banjo or banjo bolt change required.

[cstreit]

Its not a bad idea to replace the copper or aluminum compression washers when you do this, otherwise you don't need anything to seal them well.

Definitely no need to mess with the spray-bars if you don't have an oiling problem in your valve covers... Don't borrow trouble as they say.

[LakeCleElum]

I put the restrictor in my 73.5 six months ago and it improved the oil pressure dramatically. If you buy from Pelican, it comes with all the crush washers required. I don't recalled a torque figure. Snug it down good and all is well....

[afterburn 549]

On the plus side-this will be the 1st time in your life the the oil level gauge will actually work with these up dates ( or at least be close ).
I think the only question that comes to my mind is, Should a rebuild be run in w.o. them....after that by all means go for the restrictors.
Like said your O.P will go way up and better cooling ( I know that sounds weird but the Porsche report said...)

[Keith Perry]

I've read of running restrictors with the covers off and there was plenty of oil splashing around. I think the only lingering concern is a lessening of oil cooling effect on the heads. Using the figures provided by Henry, apparently 6 gal oil per hour less cooling.