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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. grumble

    grumble Well-Known Member

    Messages:
    1,184
    Location:
    Taree
    Sorry Ian for some reason I was thinking 2.1 water cooled,but at least that eliminates the head studs but
    then apart from heads you are looking at cam followers, camshaft, tappet adjusters, piston rings, bearings, wear in line bore. if the compression is down on 1 or more cylinders do a valve adjustment and drive it for a week or 2 before you tear it apart, the valves close up particularly since they removed the lead from the fuel (regardless what a lot of naysayers say regarding hardened seats etc) I found that the seats erode due to unleaded fuel and fitted a lot of these vans & beetles with the upper cylinder lube kit. You may have to adjust the valves a couple of times to get rid of the carbon build up or the recession of the seat.
     
    David H, Wayne murray and cbus like this.
  2. Ian and Shelley

    Ian and Shelley Active Member

    Messages:
    299
    Location:
    Umina Beach
    Had a play with leak down test again yesterday..

    Engine cold and results were.....

    Cylinder 1 has just 10% leak
    Cylinder 2 ....25% ish
    Cylinder 3 .30 - 35% leak
    Cylinder 4 25 - 30% leak
    Air seemed to be escaping through exhaust on No 3
    and on number 4 has leak through inlet valve..

    will redo again to be certain....
     
  3. Ian and Shelley

    Ian and Shelley Active Member

    Messages:
    299
    Location:
    Umina Beach
    If my heads are original do they have gaskets? or shims between cylinder heads and barrels?
     
  4. cbus

    cbus Well-Known Member

    Messages:
    12,799
    Location:
    sunshine coast
    Not much through crankcase breather?
    My call would be pull heads.
    Worthwhile gains to be made .
    Wouldn't be too concerned about some disturbance to barrels.
     
    grumble likes this.
  5. cbus

    cbus Well-Known Member

    Messages:
    12,799
    Location:
    sunshine coast
    What year?
    At some stage vw omitted the gaskets.
    There are arguments both ways re installing them.
    I have had no issues with reinstalling but lapped the reco head with a spare barrel.
    Next I will leave out as chasing extra compression on a sound bottom end.

    Grumbles or Ricks advice would be of more value.
     
  6. Ian and Shelley

    Ian and Shelley Active Member

    Messages:
    299
    Location:
    Umina Beach
    Its a 1976..
     
  7. grumble

    grumble Well-Known Member

    Messages:
    1,184
    Location:
    Taree
    cbus , the gasket can be replaced fairly easily by leaving the piston in the cylinder, slide the barrell back enough to access the circlips ( make sure the piston is at the top of the barrell) remove the outer circlip, slip a slide hammer through the gudgeon and carefully pull the pin carefully whist supporting the barrell, repeat the operation for the barrell on TDC on the other side, then turn the engine 1/2 turn and repeat for the other 2 barrells. Clean & fit new gaskets and reinstall, I cannot remember the year that the gaskets were eliminated but they were eliminated on the replacement heads in the 1990's so an original 76 should still have gaskets but the chances of the heads being replaced during its life is fairly high. Play it by ear and see what you have when you get the heads off Ian.
     
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  8. Barry

    Barry Well-Known Member

    Messages:
    4,849
    Location:
    Abbotsford NSW
    Geez Les
    There’s a few years of knowledge in that noggin of yours
     
    grumble likes this.
  9. grumble

    grumble Well-Known Member

    Messages:
    1,184
    Location:
    Taree
    A lot of it has fallen through the cracks over the years though Barry and I have a few senior's moments too. o_Oo_O
     
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  10. Alpal

    Alpal Moderator Staff Member

    Messages:
    8,775
    Location:
    Melbourne Bend of Islands
    Hey Les. It's all still in there, just need to wait for it to float to the surface?
    Or you need a reboot?
    Both above apply to me!
     
    grumble likes this.
  11. T1 Terry

    T1 Terry Well-Known Member

    Messages:
    1,469
    Location:
    Mannum South Australia
    If you do take the heads off, get them serviced and replace the exhaust valves. Critical on the 1600 type engine but still worth the few $$ on the later air cooled engines because the exhaust valves really cop a lot of heat.
    Personally, I'd do away with the gaskets and use Hylomar Blue http://hylomar.com/hylomar-product-range/gasket-jointing-compounds/ around the barrel bases after cleaning up thoroughly with metho on a rag to get rid of any oily film. No need to remove the cylinders, just slide them up enough to clean the faces and add some blue goo around the mating faces. Let it dry off a bit of the solvents before sliding the barrel back into place, the correct layer will sort itself once the heads compress the barrels back into the case.
    Between the cyl and head, make sure the flat surface on top of the cyl is clean and carefully polish it with very fine wet and dry paper and kero to get any carbon etc that has built up on the flat face off, but be very careful not to remove any of the carbon inside the barrel or the oil consumption could get scary for a while till it builds up a new carbon seal. If you can borrow an old cylinder barrel with a good clean flat face, use that to lap a ring in the head where the cyl face will sit when the heads are bolted up. This mostly just ensures there is nothing out of wack on the head mount face but also creates a surface for the barrel to wear a new sealing surface into .... sound weird I know, but that is what actually happens.
    The tiny grooves lapping the barrel into the head creates allow the barrel to work across that face as the head and barrel expand and contract at different rates and allows the head to seal against the barrel much faster than there just being flat aluminium to work against to make the gas tight seal.
    Doing away with the gaskets will improve the compression a little, but if you find a heap of barrel spacers under any single barrel but not the rest, there is serious work required on both the case and heads along with new barrels, a total rebuild including a full case machine in other words, so just add some Hylomar sealant to the joint and bolt it back up, but still get the heads serviced, well worth doing that bit.

    T1 Terry
     
  12. Ian and Shelley

    Ian and Shelley Active Member

    Messages:
    299
    Location:
    Umina Beach

    Thanks Terry. Appreciate the info...

    Hope to get the heads off this weekend, so we will get to see what's going on and then go from there.

    Thanks everyone
     
  13. Ian and Shelley

    Ian and Shelley Active Member

    Messages:
    299
    Location:
    Umina Beach
    Hello....heads are coming off


    Well almost, it appears the barrels are bloody well and truly stuck to the heads...when pulling the barrels come with the heads...

    What problems may I encounter if I remove heads and barrels together...

    Or is there a good location where I can lever the two apart.. .

    The heads has VW logo. Could they be originals??? Also some nice blackening on the head around No3 exhaust Valve

    Any thoughts welcomed
     

    Attached Files:

  14. tintop

    tintop Well-Known Member

    Messages:
    730
    Location:
    Canberra
    Hi Ian, all the fins are pretty fragile so I wouldn't be tapping or levering too much. I wouldn't pull them off with the cylinders unless you plan to pull the engine down that far - just take some time and get the heads free... penetrating oil or carby cleaner may free them up. Patrick
     
  15. Ian and Shelley

    Ian and Shelley Active Member

    Messages:
    299
    Location:
    Umina Beach

    Thanks, heaps of fish oil did the trick...

    Here's cylinder 3 and 4 heads..
     

    Attached Files:

  16. Ian and Shelley

    Ian and Shelley Active Member

    Messages:
    299
    Location:
    Umina Beach
    And barrels No 3 and No4
     

    Attached Files:

  17. Ian and Shelley

    Ian and Shelley Active Member

    Messages:
    299
    Location:
    Umina Beach
    Valves in No 4 look to be sitting higher and proud above head when compared to No3
     
    Last edited: May 10, 2020
  18. Barry

    Barry Well-Known Member

    Messages:
    4,849
    Location:
    Abbotsford NSW
    Is the 2nd photo head 3 or 4?
     
  19. Barry

    Barry Well-Known Member

    Messages:
    4,849
    Location:
    Abbotsford NSW
    That means 4 is recessing into the head

    gone this far - heads needs new valve seats
     
  20. Ian and Shelley

    Ian and Shelley Active Member

    Messages:
    299
    Location:
    Umina Beach
    Sorry.

    Just rechecked.
    No3 is recessed into the head and the second photo

    Photo attached showing 3 on left and 4 on right
     

    Attached Files:

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