cam oil line Restrictor/Adapter
 

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

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.

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...http://forums.pelicanparts.com/uploa...1161283072.jpg http://forums.pelicanparts.com/uploa...1161283095.jpg

That's the old style, not the restrictor.

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

Ditto, old style.

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

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.

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

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.

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.

Here's some images that may be of help:

A comparison of the two:

http://forums.pelicanparts.com/uploa...1161316466.jpg


http://forums.pelicanparts.com/uploa...1161316683.jpg


http://forums.pelicanparts.com/uploa...1161316719.jpg

Ralph

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

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.

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

No banjo or banjo bolt change required.

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. :)

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....

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...)

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.

All 911 based, air cooled Porsche engines since 89 have this type of oil flow. 946, 965, 993, TT all have reduced flow with no indication of head temp or oiling (additional wear) problems.
It is true that all of these engines ran improved cooling with duel coolers.
The duel coolers were added in conjunction with the removal of the engine mounted cooler. I'm guessing that the Porsche engineers calculated BTUs generated by the 3.6 engines (both NA & Turbo) and using hydrodynamic and thermal conductivity calculations, determined oil flow and cooler efficiency before proceeding down this path.
They (Porsche) had 9 years of production and 17 years of highway testing with no apparent indication of any problems.
Supertec has used this restricter technique since the mid 80s and we have never seen an issue in our early engines in both race and street applications.
We actually made restricters before we could buy them.
Now it's easy, just call Pelican Parts and order yours.

There was long long thread on this quite awhile ago by people that understood the thermodynamics of things... ( oil )..in the end all agreed with Porsche that cooling would be better ! I know, less sound worse,,but how do you argue with success ??
Just do it your i.c. will be happy

I upgraded on my 2.2 rebuild last year. Included the restrictors, carrera pump and relief valve mods. My oil pressure was a little too high with cold pressures around 7-8 bar. After reading some other threads here, I drilled them out a about one mm and now I see pressures about 6.5-7 cold and 4 bar at normal temps.

If you're making 4 bar at idle when the engine is hot then you have a problem.
That sounds like the wrong oil pressure sender for your gauge.
The cam fee restricters should only effect idle oil pressure and not pressure at higher RPMs.

+Thamks Henry - let me clarify. Those pressures were at 2000-3000 rpm. At idle it drops back to normal of about 1-2. I think everything is fine now.

Should I install these restrictors without any other modifications on a stock 2.2s with carrera tensioners?
Others hve mentioned bypass mods, different oil pumps, etc., will these work as a stand alone?

Yes , they will add idle oil pressure with no other modifications.

Henry,

When you were making restrictors before Porsche came out with them, what size was the orifice in the restrictors you were making?

Was the orifice size larger, smaller, or the same size as the C2 restrictor orifice size?

Thanks for the info!

1/8 INCH. slightly larger than the C2 restricter.

So now that the C2 restrictors are available do you use the C2 restrictors on all your engines or do you install 1/8" restrictors?

More specifically - what size restrictor would you use on a 3.0 SC or 3.2 Carrera engine with stock oil pumps?

Thank you greatly for the quick reply!

We use the 91 Turbo restrictors in all our engines.

Have these restrictors been proven effective after all these years? Any down side?

On the C2 /3.6 liter engines Porsche took the same approach as we did. They went with a slightly larger hole.
Our conclusion was that the factory 965 restricter was slightly too small so we bore them a to match the ones we make.

I bought the cam line restrictor from PP for my rebuild (72 2.4 to 2.5 (84 to 86mm p/c) T-to-E, oil bypass mod and a 4 rib pump (courtesy of Henry)). While I'm sure it'll be fine as-is from the discussion here, should I consider boring it out to 1/8"?

Benefits appears to be better oil pressure at idle only and less work for the scavenger pump. Anything else?

Anyone see higher engine temps or cam wear? Anyone experience too high oil pressure when cold?

Recently rebuilt my 2.4. Did the bypass mod but not the restrictors to the carerra tensioners. It does not have any oil pressure issues but more at idle when hot is somewhat desirable.

This mod scares me a bit as our engines are really oil cooled and the non roller lifters need alot of oil (zinc issue) (I cant define alot).

Collective brain trust here say to do it?

Thanks,

Chris
73 911 E

YES

The original 965 control oil control fittings were 2.5 mm or 3/32"
When I wrote that we made our fittings 1/8th, I was mistaken.
We actually bore them to 4.5mm. My conversion was in error.

Just being courious... how did you discover that the stock 2.5 mm was to narrow. If I got it right you started this mod before the factory, just with a larger port hole. Are there any experiences that made you keep the larger than the 964T testrictors?
Best regards
Pelle

Just to be clear here, 4.5MM is just a little larger than 11/64, or a #16 drill to be more accurate.
Bob B

There were no bad experiences. We used a smaller (than stock pre-91) hole to create oil pressure a lower RPM especially with turbo squirters and 4.5 mm seems to accomplish that goal.
Then the factory came out with the 965 control fitting and we used it because it was cheap and accomplished the same goal. Shortly after the 965 control fitting we noticed that Porsche elected to use a control fitting more closely aligned with our original fitting.
Guessing that they may have seen issues (we had not) we went back to our original 4.5mm bore.

Just red a couple of threads about the restrictor with all the pro and against. I am still not sure if I should fit or not, but what I do not understand is that some of the guys decided to choose something in the middle of the earlier 6mm and the new with 2.5mm, so about 4mm. But this make no sense at all, as when you look closer to the cam housing, you see below the adapter that there ist the squirt tube where the oil entries. The hole there is about 4mm (verified by drill), so an adapter of 4mm does... NOTHING. So it has at least be smaller than this, otherwise it has no effect. If you like to have something in the middle you have to fit a restrictor of about 3.3mm (half the cross section)

http://forums.pelicanparts.com/uploa...1680550753.JPG