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Thread: How do you know your 911 needs a valve adj?

  1. #1

    How do you know your 911 needs a valve adj?

    I am curious at what point do you know and how do you know you should get your 911's valve's adj?
    1976 Carrera 2.7 MFI
    Ferrari 308
    '66 Hertz Shelby 350H
    '68 Shelby 500KR
    '68 Dodge Charger
    TR 6
    450 SL
    MC40
    G35

  2. #2
    Porsche used to call for a major service (including valve adjustment) every 6000 miles, then sometime in the early eighties due to EPA requirements it became every 15,000 miles (including valve adjustment) So with no changes Porsche decreed that valve adjustment was suddenly good for over twice their original schedule. So I guess you could say 15,000 miles eh! On my own cars which I generally try to do at 7 to 8,000 miles I rarely have to make any significant adjustments. Customer cars that we see regularly
    and so we know we were the last ones making the adjustments, generally follow the same pattern of needing of not needing any significant adjustments. So how often do you do yours, and when you do are they requiring much change. Based on what we see on customer cars when in for the first time is that usually the gaps were set too loose.
    Early S Registry member #90
    R Gruppe member #138
    Fort Worth Tx.

  3. #3
    Hi Ed, how often would you recommend checking mechanical chain tensioners on a street car?

  4. #4
    I don't know, because I won't use them, but judging from a couple cars I've seen over the years that did have them, they weren't checked often enough, as the chains were so loose that it had (inadvertant) variable cam timing! I have read someplace that Porsche had used them on some race motors but I would expect that they were checked after every race. I think I would check them no less than every valve adjustment check or at 6,000 miles.
    Early S Registry member #90
    R Gruppe member #138
    Fort Worth Tx.

  5. #5
    Ed, what's your recommendation for re-torquing the camshaft housing/heads?
    John Schiavone

    Connecticut

    356 Cab, 66 911, 914-6, 911-50, 981 Cayman

  6. #6
    I have never retorqued the camshaft housing, during the era of the infamous 2.7 engines we always checked head nut torque. Generally engines with cast iron or biral cylinders I don't bother checking head nut torque,,,they don't seem to need it. Generally I don't bother with torque check on SC engines. Engines with ARP or any other aftermarket stud such as Henry's 'Super stud" I will check torque because sometimes they will need a little tightening.
    Early S Registry member #90
    R Gruppe member #138
    Fort Worth Tx.

  7. #7
    Senior Member
    Join Date
    Jun 2010
    Location
    Garden State
    Posts
    283
    I like to adjust the valves and check the rocker shaft torque at least an hour before one of rocker shafts comes loose and does a walk-about.
    I missed that appointment once and I was very lucky.

    If an exhaust valve shaft comes loose and takes a nap in the bottom of the cam box it is an inconvenience. One leaving home on the top and dancing with the camshaft can be character-building.

    If you consider silicone valve cover gaskets you can take a look inside every other time you change the oil and reuse the gasket.

    There are a few different ways and tools for adjusting the valves- maybe try them all.
    You'll likely come back to the little j shaped gauge.

    Adjusting the valves gives you an opportunity to see a lot of whats going on inside. Within reason you cannot do it too often.

  8. #8
    Senior Member
    Join Date
    Jun 2013
    Location
    lynchburg, Va
    Posts
    529
    Recently had one bank of heads rebuilt due to spring failure. Do I need to have valves adjusted xxxx miles later. Engine is 2.7 RS clone with older rebuild.
    1969 911S Targa
    1970 911S Coupe
    1973 911T w 3.2
    1972 Alfa GTV 2000

  9. #9
    Junior Member
    Join Date
    Dec 2020
    Location
    Mass
    Posts
    9
    I bought a car years back and the rpms would drop really fast and couldn't figure out why. I asked a old timer and he said my valves were to tight so I adjusted them and it improved it so much

  10. #10
    Quote Originally Posted by G69 View Post
    I like to adjust the valves and check the rocker shaft torque at least an hour before one of rocker shafts comes loose and does a walk-about.
    I missed that appointment once and I was very lucky.

    If an exhaust valve shaft comes loose and takes a nap in the bottom of the cam box it is an inconvenience. One leaving home on the top and dancing with the camshaft can be character-building.

    If you consider silicone valve cover gaskets you can take a look inside every other time you change the oil and reuse the gasket.

    There are a few different ways and tools for adjusting the valves- maybe try them all.
    You'll likely come back to the little j shaped gauge.

    Adjusting the valves gives you an opportunity to see a lot of whats going on inside. Within reason you cannot do it too often.
    If the rocker shafts are coming loose then I suspect they weren't torqued properly to begin with. I don't see them move when properly torqued. The torque spec is 180 in/lbs, you won't get that with an L head allen wrench.
    Early S Registry member #90
    R Gruppe member #138
    Fort Worth Tx.

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