engine clattering - advise needed

istoo

Well-Known Forum User
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.
 

jonbills

Membership Secretary
Site Administrator
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.
 

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

Well-Known Forum User
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
 

istoo

Well-Known Forum User
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?
 

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
 

Albrecht

Well-Known Forum User
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?

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

Well-Known Forum User
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.
 

Albrecht

Well-Known Forum User
So the cams are drilled an oil comes out of the holes in the lobes.

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

Well-Known Forum User
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
 

Farmer42

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.
 

Farmer42

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.
 

jonbills

Membership Secretary
Site Administrator
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:

Mark N

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

istoo

Well-Known Forum User
Thanks peeps
I ended up on impromptu camping trip with my son, been a way since Tuesday evening. Will catch up with garage today
 

istoo

Well-Known Forum User
What spacing for feeler gauge should I be looking for between the lash pads and the cams lobes for intake and exhaust?
 

istoo

Well-Known Forum User
Have 9thou on all bar fwd 1 and 3 which are 10thou.

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