oil restrictor on SC

[yelcab1]

would you use a turbo oil restrictor on an SC? I installed them and at idle, with cold 20W50 oil, the pressue is 80% full scale. My feeble brain says that is too high and I should switch back to stock.

Would you use the oil restrictor on your SC?

[Steve@Rennsport]

Personally, I would not install those on any 911 that didn't come with them from the Factory (91-Turbo-on).

[yelcab1]

Thanks, that is what I will do.

[hbkramer]

Steve,
I'm curious about your response.
the oil restrictor fitting "supposedly" reduces foaming in the cam boxes ,hence improved oiling to the cam chains???.if you say you would not use it for older cars/cars not designed for it, i may want to rethink it's use in my car.

You do dismiss it 's benefit (or risk of use) in older cars without any "xsplaination "
Would you elaborate on your comment pls.

I 've used it for 2 yrs,maybe 5,000 mi (street car) and notice oil pressures around 4.5-5 bar at speed ,(slightly higher than with out the restrictor)no oil leakage ,etc, however I have no proof that it is, or is not,a good improvement for my engine.
Bruce

[munsonbw]

I am also curious about these as I am putting my SC motor back together. I specifically bought them because Wayne recommended them. I am now wondering if I wasted my money...

[HarryD]

One thread of interest:

camshaft oil line restrictors- two thumbs up!

Some other threads on the topic:

Cam oil restrictor fitting - why?

Best $12 Dollars I've Spent

You can see where I stand.

[Steve@Rennsport]

Thank you, Harry.

[HarryD]

Originally Posted by Steve@Rennsport

Thank you, Harry.

Sir Steve:

I bow to your greater knowldge.

I am merely standing on the shoulders of giants.

[Steve@Rennsport]

Originally Posted by HarryD

Sir Steve:

I bow to your greater knowldge.

I am merely standing on the shoulders of giants.

You are a very funny guy,......

I shall always keep a space for you,...

[yelcab1]

I did a valve job, put the whole thing back together, installed oil restrictors, cranked the key and the engine fired up, complete with horrible valve train noises from both heads. I shut it down after 1 minute. Tonight, I pulled the muffler with the engine in the car, pulled the metal bits and pieces, and the timing case covers, and checked the valve timing (spot on), checked valve clearance (spot on) and then ... looked at the rocker cam line oil squirters, they were bone dry, not a drip of oil. It seems the restrictor did not let much oil get into the cam lines and into the valve trains.

I am convinced this is my problem. So, I am going back to old stock restrictors. Don't do this to your SC guys.

Does anyone want some free turbo oil restrictors?

[haycait911]

I put in a set on my 2.7 and was alarmed at the high pressures. I took them out and drilled them larger. ( took three tries I think, running the engine after each drilling). now oil pressure is 20 psi at idle hot, 100 psi at 3000 rpm while cool, and at 60 psi at 3000 hot.

camshaft oil line restrictors- two thumbs up!

[hbkramer]

Knowledge is power ..HP as well.

Steve, I appreciate the heads up on this subject.

Harry thanks for the redirect to Gradys comments. I am embarrassed that I missed them.

When I put them in, I took the paragraph explaining their purpose for face value,without investigating them fully.

Thanks again.

[HarryD]

Originally Posted by hbkramer

Knowledge is power ..HP as well.

Steve, I appreciate the heads up on this subject.

Harry thanks for the redirect to Gradys comments. I am embarrassed that I missed them.

When I put them in, I took the paragraph explaining their purpose for face value,without investigating them fully.

Thanks again.

Don;t feel bad. There is so much info on this board, it is easy to overlook. I was aware of the comments only because I was thinking of doing the "upgrade" but got started researching. and began to wonder about "the rest of the story".

It is probably a good thing if you have the larger pump.

[cnavarro]

Steve,

Ever considered the oil restrictors as a source of added wear on guides and such with the later engines?

[Mysterytrain]

I did some searching on the PET to find out when the restrictors first appeared. I might be missing something but it appears they used the original 901-105-361-01 from day 1 thru 94. There appears to be an early banjo bolt number 900-134-006-02 that was used from 69 thru 77. After that the part number changes to 999-134-018-02. I was not able to find the restrictors Although, I was able to find a part called a presssure pipe 964-107-118-00. I punched that number into Pelican but the system kicked it out.
Anyway, I'm still curious as to when they actually did appear on the engines and why. I'm wondering if they were a required fix when the factory decided that 2 oil coolers were just silly and that they would be able to control operating temperatures more closely with the single fender unit. Maybe the improved oil flow design would allow the engine to warm up faster? It also seems that during this time they used a beefier oil pump. I'm guessing it was required to push oil all that distance to the lone cooler. So, I'm guessing that with the additional pumping capacity they had to throttle down the flow to the cams..hence the restrictors. Any thoughts on these shade tree theories? Just seems odd that they aren't shown in the PET.

[sammyg2]

I put em on my car, no regrets and would do it again.

[patkeefe]

I have restrictors in my SC. I put them in for exactly the reasons described as "the lesser of two evils". Since I have a turbo SC, I felt the piston squirters were more important than the purported topside loss of lubrication. I have had the top end apart after I did the engine, and really didn't notice any evidence of a problem, but have considered "spliitng the difference", as Mysterytrain pointed out. I don't have any oil pressure issues, so I can afford to give back some flow volume to the top end. I kept the original hardware.

Yes, the correct answer was "bigger oil pump", but I don't have that luxury now.

Is there documented data somewhere regarding failure rates with the restrictors vs. without the restrictors?

Pat


Pat

[Steve@Rennsport]

Originally Posted by cnavarro

Steve,

Ever considered the oil restrictors as a source of added wear on guides and such with the later engines?

Hi Charles:

I've not had the time to perform a scientific study to see what effects the oil restrictors might have on these motors.

Since we go to extremes to add additional oiling (race & track motors) to the camshafts, valve springs & retainers to both cool and lubricate everything, its counterintuitive to use something that restricts oil volume and pressure to these critical parts, even in a street application.

[Mysterytrain]

Steve, I was hoping you would add to this post. Just for historical..or hysterical purposes...Did the restrictors appear before the 964, the single cooler and the higher output oil pump?

[Steve@Rennsport]

Hi Ron:

AFAIK,..these were first used on the '91 3.3 Turbo motors (all of which have the much bigger pump than the others, save the GT-3R one).

I believe these restrictors have all been superceded to these late (small orifice) ones.