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308 Service - next step question

Discussion in 'Technical Q&A' started by PhilB, Sep 17, 2009.

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  1. PhilB

    PhilB Formula 3
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    #1 PhilB, Sep 17, 2009
    I am proceeding through my major service (1984 US Spec 308QV) very carefully. Would someone mind confirming for me the next step in the service, before I proceed. I just want to bounce this off someone who has done it before.

    Car was running fine before I started, was intending on just doing the belts/tensioners and fluid/plug change, but I decided to change the cam seals as well due to a slight leak I found on the forward exhaust cam when I started the service a couple weeks back.

    I realize there are a couple of ways to find true TDC. I was going to line up all factory marks (on cams and flywheel) and leave it at that. However, I can also use the piston-stop method. I've never used a degree wheel and read the thread on using one to establish TDC, and suppose I can use that method as well.

    I am at a point now where:

    - the alternator is out of the car
    - the a/c compressor is out of the car
    - coolant rigid pipes (both sides) are off the car
    - the forward belt cover is off the car
    - the forward cam cover is off the car
    - the forward exhaust cam end plate and the distributor and wires are off the car
    - various hoses and pipes are removed or out of the way
    - the flywheel "peep hole" cover is off the car.

    Both cam belts are still on the car.

    By "forward" above, I mean cylinders 5-8, the cabin firewall side of the motor.

    I believe my next steps are:

    - Apply 36mm ratchet to crank, turn engine clockwise until I observe the TDC mark in the flywheel peep hole.
    - Then check cams for PM1-4 marks.
    - If I don't see the marks on the cams, I'm at TDC on the exhaust stroke, so continue turning the motor clockwise until I see the TDC mark on the flywheel again.
    - Then check the cams again for the marks. At this point, I should see the marks on the cams and know I'm at TDC intake stroke.

    Once I have all the marks lined up, I can then:
    - Loosen and remove tension bearing
    - Remove the cam belt on the forward bank

    And after the belt removal would be to remove the cams. Do I need to be concerned with anything popping off or flying out of the car when I remove the cams - anything under loaded pressure that's going to want to fly out once the cam journals are loosened?

    I appreciate any advice you may have on this,
    Phil
     
  2. Ferraripilot

    Ferraripilot F1 World Champ
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    #2 Ferraripilot, Sep 17, 2009
    The only reason to remove the cams would be if you needed to replace the shims under the cams due to one or several not being the correct clearance. There is also no need for a degree wheel if the car was running well prior to the service. When changing the belts, it would be a good idea to lock in the cams. There are a couple threads showing different cam locking mechanisms people have crafted, but my method is to place a piece of a matchbook cover or construction paper under the nearest cam journal and locking it down very gently. Do not use much pressure when doing this because all you need is for the cam to not move.

    If the cam shim clearance has not been checked lately, I recommend doing so prior to pulling the old belts. Get comfortable with turning the engine and checking shims. It takes time the first time a person does it but it helps you become even more comfortable with the engine.
     
  3. M.James

    M.James F1 Rookie

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    #3 M.James, Sep 17, 2009
    Last edited: Sep 17, 2009
    He's already stated that he's replacing cam seals - therefore, the cams MUST come out to replace the seals at the ends of the cams. Once the cams come out, forget about cam-locks at that stage, as there's nothing to lock-down.

    I'd keep track of those special Belleville washers under the camshaft cap nuts - you don't want to 'lose' one somewhere inside the engine. IMHO, those should be replaced with new OEM Belleville washers as they can lose their spring/elasticity over time. The nuts for the camshaft caps should be loosened over the lenth of the camshaft slowly and evenly. You'll want to pay special attention to the camshaft cap numbers, their sequence, and orientation depending on the camshaft you're attempting to 'free'.

    Also, check the torque specs on those nuts during re-assembly. Take your ever-loving time, don't rush at all.
     
  4. PhilB

    PhilB Formula 3
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    #4 PhilB, Sep 17, 2009
    Thanks for the advice on the shims.

    I thought the cams had to be removed to change the seals...?

    Phil
     
  5. PhilB

    PhilB Formula 3
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    #5 PhilB, Sep 17, 2009
    That's what I thought.

    Phil
     
  6. M.James

    M.James F1 Rookie

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    #6 M.James, Sep 17, 2009
    The cam-seal rings will require a delicate hand - you don't want to marr the inner surface where either seal resides so I'd be VERY careful with metal tools when you attempt to pry-out the old seals. You pretty-much have to use a pry-bar or large screwdriver to remove the outer seal, as those seals are a tight press-fit.
     
  7. Ferraripilot

    Ferraripilot F1 World Champ
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    #7 Ferraripilot, Sep 17, 2009
    yup you're right. missed that when breezing over your post!

    when sealing the cam covers, Hondabond is a good option. I like to place a dot of RTV at the apex where the cam seal meets the aluminum between the two covers. This was at the advice of another fchatter and it has been holding up fine since.
     
  8. PhilB

    PhilB Formula 3
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    #8 PhilB, Sep 17, 2009
    Yup, already read about the Hondabond and picked up a tube.

    So, nothing will go flying out when I remove those cams....?

    Also, when torquing the heads, does everyone use the special tool, or is there a trick?

    Thanks again,
    Phil
     
  9. PhilB

    PhilB Formula 3
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    #9 PhilB, Sep 17, 2009
    I'm presuming you're referring to the cam seal cover (part #117257) and not the two sealing rings (#'s 105389 and 117275).

    Can this seal cover be removed once the cam is removed? Or does the seal have to be removed first?

    Phil
     

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