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Valve thrown advice please

Discussion in 'Engine & Transmission' started by Winged, Sep 13, 2017.

  1. Mr Beckstar

    Mr Beckstar Well-Known Member

    Messages:
    985
    Location:
    Bateau Bay, NSW
    If you haven’t done the tests, then you’ve probably got to strip the valves out of the heads and check the seats are installed properly in the head and that the valve grind is good. Check for cracks, check sealing surfaces against barrels are in good order, etc. Check lifters, cam lobes, push rods, rocker arms, etc.
     
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  2. Winged

    Winged Active Member

    Messages:
    206
    Location:
    Huon Valley
    20190810_124837_resized.jpg 20190810_124859_resized.jpg 20190810_124829_resized.jpg
    Hi cbus, pulled out the lifters yesterday. They look good, as do the cam lobes. No sign of damage or deep scoring.
    Guess that's some good news. Pics look a bit deceptive due to oil and colouration. The lifter faces are smooth and level. 20190810_124837_resized.jpg 20190810_124859_resized.jpg 20190810_124829_resized.jpg 20190810_130734_resized.jpg
     
  3. Winged

    Winged Active Member

    Messages:
    206
    Location:
    Huon Valley
    Hi Omelette and thanks for chiming in. I had the timing set at 7.5. Its a CJ block and Ive always set it there. The sticker on the fan housing agrees with me.
    I had taken it to a experienced VW guy in Hobart prior to going away. He tuned the carbs and did the tappets. No mention of a timing change so i assume it was still at 7.5.
     
  4. Winged

    Winged Active Member

    Messages:
    206
    Location:
    Huon Valley
    Hi Adrian, has taken me a week or more just to get the gumption to look at it again.
    Andrew Robinson mentioned #3 was tight despite me adjusting not many days before taking it to him. So it could have tightened up again.
    I also noticed during disassembly that the heater box to head nuts seemed looser than others at #3 with evidence of blowing on the brass seal. I'm doubtful that I retorqued them after the initial assembly.
     
    Mordred likes this.
  5. Winged

    Winged Active Member

    Messages:
    206
    Location:
    Huon Valley
    Thanks Mr Beckstar, some great observations. Unfortunately I didn't do a compression test prior to removal, can this be done by hand with the engine out? Wouldve been a great help now. I cant see any obvious damage to lobes, lifters, valves or cylinder/head surface. Does a poorly seated valve always appear visually out?
    During disassembly the heads seemed evenly torqued, but as mentioned #3 heater box-head seemed loose and had colouration consistent with leakage.
    Thanks
     
  6. Wayne murray

    Wayne murray Well-Known Member

    Messages:
    2,854
    Location:
    Seven hills
    They should be if new slightly convex mushroom shape from the middle as the high point.
     
  7. Mr Beckstar

    Mr Beckstar Well-Known Member

    Messages:
    985
    Location:
    Bateau Bay, NSW
    You could easily do a leak down test on the bench but you would have to put the heads on.

    However, if you’ve got the heads off you may as well just disassemble them and inspect all the valve seats. A poorly seated valve will be obvious when you look at the sealing surfaces of the seat and the valve. Also, consider getting the valve seats redone as per the link early in the thread. If one of your seats is dropping, then I’d say it’s a no-brainer.
     
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  8. cbus

    cbus Well-Known Member

    Messages:
    11,701
    Location:
    sunshine coast
    Mr Beckstar likes this.
  9. grumble

    grumble Well-Known Member

    Messages:
    1,007
    Location:
    Taree
    After the valves and seats are cleaned a smear of bearing blue on the face of the valve pop the valve into the head turn it 1/4 turn pull it and look at the seat and valve, wipe the blue from the seat, pop the valve in again a 1/4 turn with a little pressure on the middle of the valve and the blue from the valve should return to the seat. If not it means a valve service.
     
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  10. tintop

    tintop Well-Known Member

    Messages:
    470
    Location:
    Canberra
    Hi Winged

    x2 for everything Mr Beckstar has said...how about some pics with the heads renumbered correctly so it's easier to match to the cylinders without too much thought

    not being completely run in, it wouldn't be uncommon for a bit of oil to come through...so hard to diagnose carbon for now (and it was recently running rough)

    you mention 'perhaps in hindsight seized' but is there any evidence of that - could/can you turn it by hand? (bit difficult now because the cylinders will bounce around)

    also - that orange marking in the cylinders and on the pistons - is that the flash from the camera? If you do rotate the engine is everything similar on the other two?

    not having heard the 'ticky rattle' makes it difficult, but the other symptoms you describe sound like you could have picked up some water or dirt in the idling circuit of one or both carbies so it won't idle properly (or stall)...if it's in the main jet and accelerator pump as well it would also lack power and start making noises as it misfires (lean mixture leads to incomplete combustion of fuel which then ignites in the hot exhaust)...bit late now but that would have been the first place I'd have looked (understandable for you with your valve history that you pulled the heads off though)

    loose exhaust manifold bolts will get the exhaust valves hotter (or burn them out) as it draws in extra oxygen..check the copper washers on your hot exhaust valves to see if there's evidence they weren't seated properly

    I wouldn't expect the new heads to have a problem unless the tappets were too tight - or as above the exhaust was loose - but it is possible. as per previous posts you could pull all or some of the valves and check if they are seating properly. bouncing seats also make a ticky rattle (usually on deceleration when hot being the first sign) and may not be loose on a cold head.

    Hopefully you don't find anything nasty and can reassemble it - make sure you have clean fuel - drain the carbies (into a container and check for water) look for dirt - blow through all the passages.

    Patrick
     
  11. Winged

    Winged Active Member

    Messages:
    206
    Location:
    Huon Valley
    Hi Patrick, the orange on the pistons isn't the flash! Im perplexed as the why its both 3 & 1? There was a history of say 500kms + with poor running. They are Porsche pistons if that makes any difference.
    Heads:
    20190812_112111_resized.jpg 20190812_112311_resized.jpg

    Am i right that to remove valves requires a press of sorts?

    Exhaust mani:
    20190812_112111_resized.jpg 20190812_112311_resized.jpg 20190812_112747_resized.jpg 20190812_112751_resized.jpg 20190812_112348_resized.jpg

    #3's copper ring has significant ware. Underneath head pic is also #3.


    Spark plugs
    20190812_111637_resized.jpg 20190812_111657_resized.jpg #3

    Will do a compression test next.

    Thanks for the advice
     
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  12. Mordred

    Mordred Super Moderator Staff Member

    Messages:
    2,809
    Location:
    Penna, Hobart
    I might be speaking out of turn here, but those copper rings look like they haven't sealed properly and have burned with exhaust gas escaping past them. If they had sealed there shouldn't be much discoloration on the outside.
    I was on the understanding that they need to be annealed by heating up to cherry red with a gas torch and then dump them into cold water to soften them before you fit them. I suppose the thinking is the softer copper takes up the imperfections between the steel and the aluminium. I have always done this and never had an issue.
    You also want to make sure that the exhaust manifolds are flat and also level against each other with a straight edge and if they aren't they aren't going to seal no matter how soft the copper rings are. A file is all I have had to use to touch them up.


    Adrian
     
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  13. tintop

    tintop Well-Known Member

    Messages:
    470
    Location:
    Canberra
    Hi Winged...here's a way you can get the valves out without a valve spring compressor...a few washers and a spanner (and a block of wood under the valve head)...you only push down on one side of the spring like this but that's enough to pick the collets out with something pointy. Patrick Photo0950.jpg
     
    Last edited: Aug 14, 2019 at 8:16 PM
  14. Mr Beckstar

    Mr Beckstar Well-Known Member

    Messages:
    985
    Location:
    Bateau Bay, NSW
    I’m going to have a bit of a guess here as it’s hard to really have a good look with the photo’s, but it’s worth considering for yourself.

    I’m thinking all four pots are running lean, but pots 2 and 4 have enough oil burn (i.e. bypassing the piston rings) to colour the full piston area and the exhaust valve.

    Yes, tintop shows a method above, but if I were you I’d buy a valve spring compressor. They’re not that expensive and makes the job easy. It’s especially important to make sure the collets are located correctly when assembling and the valve spring compressor gives you the most sure way to achieve that.

    The wear on the ring is misalignment. The copper ring has either fallen out of place during assembly or there’s something wrong with the alignment of the exhaust flange with the head. Close inspection is required to make sure everything will go together properly. I agree with Mordred’s comments. Plus, check that the “ears” on the manifold do not bottom out on the head somewhere rather than squash the copper gasket. I agree with Mordred that you may have to file the faces of the manifold, but it may have been done many times without checking for bottoming out.

    Looking at the sides of the spark plugs is not helpful. The view you’ve shown for #3 is what’s needed for all of them. It’s important to look at the insulation around the centre electrode as well as the curved earth tab and the outer ring at the end of the threads.
     
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  15. Winged

    Winged Active Member

    Messages:
    206
    Location:
    Huon Valley
    Looking at the sides of the spark plugs is not helpful. The view you’ve shown for #3 is what’s needed for all of them.

    Thanks for your help Mr Beckstar. Hope these are better.

    20190820_001728(1).jpg 20190820_001746(1).jpg 20190820_001814(1).jpg 20190820_001832(1).jpg
     
  16. Winged

    Winged Active Member

    Messages:
    206
    Location:
    Huon Valley
    Is there a potential problem with 1 & 3 and rings then? Hence the brassy areas on the piston surface?
     

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