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Pulling heads off for a visual? or a costly waste of time

Discussion in 'Engine & Transmission' started by Ian and Shelley, Apr 28, 2020.

  1. Ian and Shelley

    Ian and Shelley Active Member

    Messages:
    299
    Location:
    Umina Beach
    Hi

    Lockdown is causing restless hands...

    As I have motor out for clutch fix , Is there any benefit in removing the heads for a visual inspection to assess condition of valves etc?

    If the heads are removed is it then necessary to purchase new head bolts etc to reattach?

    Thanks

    ian
     
  2. Barry

    Barry Well-Known Member

    Messages:
    4,852
    Location:
    Abbotsford NSW
    No new head bolts.

    biggest problem is if you break the seal at the bottom of the barrels when you take the heads off.

    then you will need to make the barrels out, clean them up, put pistons back in and reseal

    not the end of the world but just more work.
     
  3. Ian and Shelley

    Ian and Shelley Active Member

    Messages:
    299
    Location:
    Umina Beach

    Thanks Barry

    It might be worth playing with...

    You mention....The biggest problem is if you break the seal at the bottom of the barrels when you take the heads off.

    How are these barrels sealed? Is it just a tight snug fit ? any sealant to reapply if hey come apart?

    Thanks again
     
  4. Barry

    Barry Well-Known Member

    Messages:
    4,852
    Location:
    Abbotsford NSW
    Yes - there is sealant there

    Some caution required as you are opening the case to the world.
    Don’t want to go dropping any bits of sealant in there.
     
  5. grumble

    grumble Well-Known Member

    Messages:
    1,184
    Location:
    Taree
    Another couple of things to be aware of are the cylinder barrels are often (90%) seized in the head and can be a real bugger to remove, the head studs may be etched and snap when tightening the heads making things really interesting. Not being negative just making you aware of a couple of potential problems.
     
    oldman likes this.
  6. tintop

    tintop Well-Known Member

    Messages:
    730
    Location:
    Canberra
    Hi Ian, do you have a reason to take them off? If not, I wouldn't disturb things. Patrick
     
    grumble, Whitie and oldman like this.
  7. Ian and Shelley

    Ian and Shelley Active Member

    Messages:
    299
    Location:
    Umina Beach
    I think the heads needs replacing and I plan to do a rebuild at some point and was thinking of taking a peek out of curiosity....

    Got some free time and just fancied a tinker...
     
  8. Grantus

    Grantus Well-Known Member

    Messages:
    17,243
    Location:
    Southern ACT
    As long as you are aware of any pitfalls............ what’s the worst that can happen? :rolleyes:

    Total rebuild earlier than you expected, if it gets messy, I guess.. ;)
     
    grumble and Ian and Shelley like this.
  9. Ian and Shelley

    Ian and Shelley Active Member

    Messages:
    299
    Location:
    Umina Beach
    That's what I am thinking too....

    Although i have to fix this clutch issue first..
     
  10. tintop

    tintop Well-Known Member

    Messages:
    730
    Location:
    Canberra
    Fair enough, what make you think the heads need replacing? apart from them often being the weakest link :)
     
  11. Ian and Shelley

    Ian and Shelley Active Member

    Messages:
    299
    Location:
    Umina Beach
    Compression tests results were
    1 -100psi
    2 - 90psi
    3 - between 75-90psi
    4 -95 psi

    All a bit rubbish

    Leak down test also indicated cylinder 3 having biggest leak ( cannot remember results just now)
     
  12. Barry

    Barry Well-Known Member

    Messages:
    4,852
    Location:
    Abbotsford NSW
    If #3 was 90 I wouldn’t worry.

    if it’s 75 it is on it’s way out.

    your call I guess.

    good chance you are going to find a broken ring and you will need parts for that.

    also going to need to clean the ring landings before putting it back together.

    might even find a small blow mark on #3 head seal that may require a kiss from a head cut.
    if that’s the case - you may as well have valves, guides and seats looked at.

    Oh - you will need to rehone the cylinders. do you have access to that gadget?

    where does it end???

    just saying this will take a while.
    Time, effort and money.
    Now mightn’t be the time.
    Your call - personally I would fix the clutch and start collecting pieces and preparing.
     
    oldman likes this.
  13. tintop

    tintop Well-Known Member

    Messages:
    730
    Location:
    Canberra
    Hi Ian,

    yep, as per Barry's post if your varying compression on 3 was dependent on squirting oil into the cylinder then you may need to dig further than heads
    (or could be valve related if not). What do the spark plugs look like?

    For your 1800 engine, Bentley says:
    New 85-135 psi (quite a range)
    Wear limit 71 psi
    Max 28 difference between cylinders

    Patrick
     
  14. Ian and Shelley

    Ian and Shelley Active Member

    Messages:
    299
    Location:
    Umina Beach

    Thank you all


    Appreciate the feedback..

    Let's get the clutch judder sorted and leave all the extras for another time..

    It's runs all ok and I think best not to fiddle for now..
    Keep motor as is and enjoy what works


    Thanks everyone
     
    Barry likes this.
  15. cbus

    cbus Well-Known Member

    Messages:
    12,814
    Location:
    sunshine coast
    If you still have the leak down tester and motor still complete you could repeat the leak down test.
    It will give an indication of ring or valve.
     
  16. Ian and Shelley

    Ian and Shelley Active Member

    Messages:
    299
    Location:
    Umina Beach
    Thanks. Will do another leak down test, easy to do now motor out
     
  17. Ian and Shelley

    Ian and Shelley Active Member

    Messages:
    299
    Location:
    Umina Beach
    Sorry...Another question..

    I don't have that thermostatic thing to open and close flaps to oil cooler...

    Currently it's in closed/ covered position
     

    Attached Files:

  18. Ian and Shelley

    Ian and Shelley Active Member

    Messages:
    299
    Location:
    Umina Beach
    Should it be in the open position. Which way allows air to flow over oil cooler..

    Some dirt and debris over oil cooler...

    Will look for refitting thermostatic thing
     

    Attached Files:

  19. cbus

    cbus Well-Known Member

    Messages:
    12,814
    Location:
    sunshine coast
    That position is ok.
    It is diverting air over both engine and oil cooler.
    Put fingers inside fan fansing and you will feel the gap to oil cooler.
    Good idea to degrease cooler.
     
  20. cbus

    cbus Well-Known Member

    Messages:
    12,814
    Location:
    sunshine coast
    When you do the leak down test expect some blowby out of crankcase breather.
    Some usualy exits and the engine will be cold so not at operating clearances.
    Main check will be exhaust valves( out exhaust, and inlet valves( carbs )
    If valves are hardly detectable to none and you have considerable loss, especially on 3, then it's likely compression rings worn or broken?

    Plugs won't be a big help if engine wasn't last run at hwy speeds but might give an indication of history.

    If manifolds off you can get some photos of back of valves while they are in open position
     

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