engine clattering - advise needed | The Z Club of Great Britain
  1. The Z Club relies on the support of it's paid members - join the club or renew your membership here.

engine clattering - advise needed

Discussion in 'Engine' started by istoo, Jul 19, 2021.

  1. istoo

    istoo
    Z Club Member

    Bear with me here.

    Two weeks ago Iwas coming back from Sunday morning meet at a local cafe, stopped by a pals house on the 10 mile drive home and the engine sounded noisey, I am not a mechanic but know the tappety noise (my old quattros all made the same clattering on idle). Left the car for an hour started and it was quieter, set off home, not until passing a wall near my house i could hear it, was notably louder.

    It was low on oil, but not off the low marker on dipstick, I wasnt hammering it, did top it up will 500ml of a slightly heavier weight oil a day beforehand.

    I did take the rocker off to check the cams were getting oil which they were. Beyond that i put it to a trusted garage. Their initial feedback was smallend gone, maybe look for a new engine then diagnose the old one. They havent had the engine stripped down to inspect yet, but I beleive we are at that point. feedback from garage...

    "start the engine up from cold with bonnet open on Friday and we both thought cam noise ‍♂️ to be honest I can't say,I did think I would have seen more wear on the cam or followers ie more play in at least 1 or 2 but all felt the same and chain definitely has too much play so unsure of the noise,it is definitely effected by oil pressure so a small end probably not the case. Yea it's where do we go from here ‍♂️lol chain guides worn too so what to do?"

    I do want to keep the engine and fix in an ideal world, but dont want to splash out on new cams lifters etc if that isnt the likely route cause etc. Although I was planning that as this years job to tackle myself anyway. Will get a video of it running to confirm noises for all but really trying to avoid starting it for obvious reasons.

    Looking for guidance from the wise and the good here.
     
  2. jonbills

    jonbills
    ZClub Administrator
    Moderator

    Unusual, but maybe the chain tensioner is failing. That would account for worn guides, slack chain and noise. but you also burned at least 500ml oil on a (short?) Saturday morning jaunt.
    A recording of the sound might help and a video showing the chain and how much slack it has.
     
  3. Albrecht

    Albrecht Well-Known Forum User

    What engine is it exactly?

    Couple of weeks ago I was asked to have a look at a car that was "not running right". Engine was single carburettor 'sedan' type L24 with E88 head and camshaft oil spray bar. Owner had been messing around with plugs, plug leads, points and carburettor settings. Engine was struggling to idle and shuddering like crazy.

    He started it up to show me the symptoms and I was shocked at how noisy it was. Loud clattering from back half of top end. I told him to shut it off immediately and asked him why he hadn't mentioned the noises. He said he hadn't noticed them!

    I had a hunch. Popped off the valve cover and - sure enough - camshaft spray bar had broken at the joint/mount over valves for cylinders 5 & 6, and the broken end was sitting between the valve springs. Camshaft lobes for cylinders 5 & 6 hadn't been getting oil for some time. Camshaft lobe wear and - guessing - some damage to exhaust valve & seat on #6 as difficult to get it to run right and plug fouled.

    I found a good used spray bar and fitted it for him. Re-set valve clearances and much better than before (no more clattering) but I reckon damage done.

    So, if your engine has a camshaft oil spray bar, best to pop the valve cover and check it out.
     
    istoo and AliK like this.
  4. istoo

    istoo
    Z Club Member

    Outstanding

    Engine in questions is an U.K. (I believe)
    L24 with an E88 head, on stand Hitachis otherwise virtually standard.

    I haven’t messing with timing. It generally idles well a bit splutters when cold but warms to a steady idle quickly

    that’s great info
    Will go for a poke around tomorrow with mechanic and see what’s what. PS I have told missus subs it might need some work. So using that as a plausible excuse
     
  5. istoo

    istoo
    Z Club Member

    To add
    If this is my issue also, and there is damage done. What damage would that be, ie what do I need to look for also?
     
  6. Albrecht

    Albrecht Well-Known Forum User

    Just to add some photos of what I found: Looked to me as though someone had tried to 'fix' it in the past by gluing it back together with red Hermetite. Obviously not Hermetite enough...

    Broken spray bar-1.jpg Broken spray bar-2.jpg Broken spray bar-3.jpg Broken spray bar-4.jpg
     
    istoo likes this.
  7. Albrecht

    Albrecht Well-Known Forum User

    First thing would be (visible) cam lobe damage, possible damage to valve spring cap/lifter/spring, possible damage to valve(s) and valve seat(s). Compression check might help to diagnose valve/seat damage.

    This one seemed fairly lucky in that the broken part had fallen down between valve springs and lay out of harms way. Could have caused all sorts of damage by getting more caught up in valve train.

    Edited to add that as both yourself and the garage have had the rocker cover off and not seen anything untoward, its probably not the camshaft oil spray bar that's at fault. However, it is worth checking that it hasn't been missed. Sometimes these things hide in plain sight.
     
    istoo likes this.
  8. istoo

    istoo
    Z Club Member

    Superb, i will report back tomorrow evening once had a look.
    so interestingly when i bought it the garage commented that the cam lobes looked quite worn and could do with regrind/new cams in the future. thus my plans for this year. i wonder is the lifters have never been adjust rights as its always had a little bit of noise, never much but enogiuh to notice. having nohting to compare it to assume its was normal.

    pics add aiding diagnosis.

    Thanks again. appreciate this.
     
  9. istoo

    istoo
    Z Club Member

    So the cams are drilled an oil comes out of the holes in the lobes.
     
  10. Albrecht

    Albrecht Well-Known Forum User

    Essentially there are two types of camshaft oiling systems on the L6 engines: Externally oiled (via a spray bar mounted to the cam towers) and internally oiled (where the cam blank is drilled and there is an oiling hole in each lobe).

    Most L24 engines, and that would include those fitted as standard equipment on HLS30 & HS30 '240z' variants, left the factory with the externally oiled, spray bar type setup. Internally oiled cams came slightly later.
     
    istoo likes this.
  11. istoo

    istoo
    Z Club Member

    will have a look around the valve gear / lifters / lashpads. assume that the lashpads spacings to the cams maybe off regardless of spraybar or oiled cams
     
  12. Farmer42

    Farmer42
    Z Club Member

    I would also advise checking your valve timing on the camshaft sprockets to make sure it is all still in sync. If your timing chain is rattly there is a small possibility that it may have slipped a tooth and thrown your valve timing out which may cause noise and damage.
     
  13. istoo

    istoo
    Z Club Member

  14. Farmer42

    Farmer42
    Z Club Member

    That's definitely top end. Have you checked that you still have all your lash pads in place on the top of the valve springs? It has been known for them to ping out which will give you a really loud tappety sound like that.
     
    istoo likes this.
  15. jonbills

    jonbills
    ZClub Administrator
    Moderator

    I agree with Paul, there's a lot of top end noise there, but as you move round the front to the other side there's something more like a rod knock.
     
    Last edited: Jul 23, 2021
    istoo likes this.
  16. Mark N

    Mark N
    Z Club Member

    Have you checked your oil for metal particles, it might give you an indication if something is being chewed up?
     
  17. istoo

    istoo
    Z Club Member

    Thanks peeps
    I ended up on impromptu camping trip with my son, been a way since Tuesday evening. Will catch up with garage today
     
  18. istoo

    istoo
    Z Club Member

    What spacing for feeler gauge should I be looking for between the lash pads and the cams lobes for intake and exhaust?
     
  19. istoo

    istoo
    Z Club Member

    Have 9thou on all bar fwd 1 and 3 which are 10thou.

    The cam chain is slack. The guides look pretty worn to me.
     
  20. istoo

    istoo
    Z Club Member

Share This Page