Page 2 of 2 FirstFirst 12
Results 11 to 19 of 19

Thread: Restrictor fittings

  1. #11
    Senior Member
    Join Date
    Dec 2008
    Location
    Black Mountain, NC
    Posts
    539
    Changed back to the stock oil fittings today, measuring the stock one more accurately it is about 6.19mm and the replacement is as reported at 2.5. I have attached pics which include the Porsche P/N for the set I had, also for some who may not know what is in their motor a side view with the groove cut into the hex indicated the restrictor fitting. Also as a note while fittings were off looking at the oil line fitting the ID of the steel line that gos into the banjo fitting may be slightly smaller than the 6.1 diameter in the fitting, maybe 5.7 with a small hole gauge but very hard to get a good reading, would be interesting to cut a banjo in half to get a good measurement but no spares or old lines.
    In doing this I remembered debating about drilling them to some where between 6 & 2.5 but went with the as suggested restrictor, not any more, may drill these to 4.5 but doubt I will see any O.P. issues as I did not prior to the change.

    Best Regards
    Attached Images Attached Images   

  2. #12
    Member AKAMick's Avatar
    Join Date
    Sep 2018
    Location
    77°50′47″S 166°40′06″E
    Posts
    86
    Quote Originally Posted by Jerry L View Post
    Changed back to the stock oil fittings today, measuring the stock one more accurately it is about 6.19mm and the replacement is as reported at 2.5. I have attached pics which include the Porsche P/N for the set I had, also for some who may not know what is in their motor a side view with the groove cut into the hex indicated the restrictor fitting. Also as a note while fittings were off looking at the oil line fitting the ID of the steel line that gos into the banjo fitting may be slightly smaller than the 6.1 diameter in the fitting, maybe 5.7 with a small hole gauge but very hard to get a good reading, would be interesting to cut a banjo in half to get a good measurement but no spares or old lines.
    In doing this I remembered debating about drilling them to some where between 6 & 2.5 but went with the as suggested restrictor, not any more, may drill these to 4.5 but doubt I will see any O.P. issues as I did not prior to the change.

    Best Regards
    Did you have any problems because of the restrictors that necessitated the removal and refit the old style fitting?
    Current fleet, mostly rubbish automobiles and other assorted junk.

  3. #13
    Senior Member
    Join Date
    Dec 2008
    Location
    Black Mountain, NC
    Posts
    539
    No just reading this thread and Ed's comment, he knows these cars. I made me think to when I put them in it looked crazy small and a major difference in flow. at that time I debated drilling them to something in between, the note on Henry drilling them to 4.5 is interesting.
    The theory was to aid low RPM oil pressure, my car never had a problem it had a fresh rebuild before I got it, so now I will look at two things, oil pressure at idle when hot and also oil temp as we know the heads are the hottest place on these cars and flowing more oil over them cant hurt and may bring my oil temp down some although it is not high.
    Looking at them it looks crazy different flow capability. Cool and rainy here may take a bit to get a good read on this, I think I will drill them to 4.5 before putting them back in the spares.

    Regards

  4. #14
    I asked about these once at the Porsche training center. They weren’t too definitive in their answers but it seems the oil fed tensioner update was a part of it as they wanted more oil pressure in that part of the circuit. FWIW....

  5. #15
    There was an article about these devices published in the Mid Ohio PCA Magazine some years ago,

    Tech Talk 911 Camshaft Oiling Update By Steve Grosekemper, San Diego Region

    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 6mm orifice
    and the new one with the 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 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 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.
    Special thanks goes out to Lee Rice for his help
    and initiative regarding this article.
    Good Luck.
    TOM

  6. #16
    Senior Member
    Join Date
    Dec 2008
    Location
    Black Mountain, NC
    Posts
    539
    Quote Originally Posted by Bridgeguy View Post
    I asked about these once at the Porsche training center. They weren’t too definitive in their answers but it seems the oil fed tensioner update was a part of it as they wanted more oil pressure in that part of the circuit. FWIW....
    This looks to make sense when looking at the oil line going to the Oil Fed tensioners, I have the 930 tensioners and the wide base idlers so I think I will watch the oil pressure & temp and if I see anything disturbing I may switch back with maybe a 4.5mm dia. I will also pull out a set of cam housings in the parts cabinet and look at the oiling holes in them out of curiosity.

    Regards

  7. #17
    I had never heard that reason before,,,,but then I think of all the cars that we've updated the tensioners without using restrictors, and have never seen a problem, so I tend to wonder if that isn't "overthinking" the situation. I'm sure not going to start using them.
    Early S Registry member #90
    R Gruppe member #138
    Fort Worth Tx.

  8. #18
    Quote Originally Posted by edmayo View Post
    I had never heard that reason before,,,,but then I think of all the cars that we've updated the tensioners without using restrictors, and have never seen a problem, so I tend to wonder if that isn't "overthinking" the situation. I'm sure not going to start using them.
    I agree. Never a second thought given.
    Early S Registry #235
    rgruppe #111

  9. #19
    Member #226 R Gruppe Life Member #147
    Join Date
    Feb 2009
    Location
    Portland, Oregon
    Posts
    2,343
    +1 again. I don’t think oil pressure is the an issue. I took a motor apart because of really low oil pressure, like 30psi max, it had maybe 5000 miles since an overhaul. An oil plug had come out of a re-ground crank at one of the journals causing the low pressure. There wasn’t a mark in any of the bearings. It was kind of a wake up call about oil volume. Gordon

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Message Board Disclaimer and Terms of Use
This is a public forum. Messages posted here can be viewed by the public. The Early 911S Registry is not responsible for messages posted in its online forums, and any message will express the views of the author and not the Early 911S Registry. Use of online forums shall constitute the agreement of the user not to post anything of religious or political content, false and defamatory, inaccurate, abusive, vulgar, hateful, harassing, obscene, profane, sexually oriented, threatening, invasive of a person's privacy, or otherwise to violate the law and the further agreement of the user to be solely responsible for and hold the Early 911S Registry harmless in the event of any claim based on their message. Any viewer who finds a message objectionable should contact us immediately by email. The Early 911S Registry has the ability to remove objectionable messages and we will make every effort to do so, within a reasonable time frame, if we determine that removal is necessary.