Mysterious knock or loud tick in engine

This site contains affiliate links for which LandyZone may be compensated if you make a purchase.
I suppose if it changes under load as he suggests it could be a gasket blowing as cylinder pressure increases. That would give a sort of ticking noise. You can also get a sort of ticking noise as the manifold expands and contracts on the studs. But that is normally when the engine switched off and cooling.
 
Last edited:
On my 3.9 Classic, I had a ticking noise that was dependant on engine speed...I thought initialy it was a dropped valve, Push Rod or duff Hydraulic Follower....turned out to be a blown exhaust manifold gasket....

Not saying it is, but might be worth a check with a high power torch in the dusk to see if you can see escaping exhaust gases!!
 
Saint.V8 said:
On my 3.9 Classic, I had a ticking noise that was dependant on engine speed...I thought initialy it was a dropped valve, Push Rod or duff Hydraulic Follower....turned out to be a blown exhaust manifold gasket....

Not saying it is, but might be worth a check with a high power torch in the dusk to see if you can see escaping exhaust gases!!
Click to expand...


That is the problem here Ant, he says it is not engine speed related. That is what makes it hard to pick. That only leaves vibration for me.
 
wammers said:
That is the problem here Ant, he says it is not engine speed related. That is what makes it hard to pick. That only leaves vibration for me.
Click to expand...
Hmmm Fair Point....

After reading back, whilst the OP doesn't want the potential needless effort of taking the heads off, it may be the only resort....

Even just removing the Plenum, Trumpets and Inlet Manifold, remove the valley gasket to look at the rods, lifters and Cam lobes would be a start, as he indicates it is coming from under the Inlet Manifold....

My option would be to whip those items off and take a goosey....could be a duff follower bouncing around intermittently causing the slight engine rocking due to in-efficent valve opening times, but then it behaves and not ticking sound...then it looses internal hydraulic pressure, and bounces around again causing the ticking, until it pumps itself back up again.

This would be worse when the oil is cold and thicker, but getting better once it is warm.

When it happens under load my thoughts would be piston gudgeon pin bearings, the big ends or Crankshaft Bearings as the extra load would cause the knocking to become worse due to the extra force these components will have to stand up to. Usually (I could be wrong) the camshaft, lifters and valves don't have anywhere as much force applied during load conditions, so if it is worse under load, it is time to look at what is stressed during this time, which would be Pistons, Con Rods, Gudgeons, Big Ends, Crankshaft Bearings, Liners etc....

But the OP seems to not want to strip a duff engine due to it being a waste of time (who would blame him - I sure wouldn't want to do that much work if it is only going to go to the scrapper in the sky anyway), but unless he has a pot of spare cash for a new engine/vehicle, the only option I can see is to get into the engine internals and see what is a miss, unfortunalty
 
Last edited:
Saint.V8 said:
Hmmm Fair Point....

After reading back, whilst the OP doesn't want the potential needless effort of taking the heads off, it may be the only resort....

Even just removing the Plenum, Trumpets and Inlet Manifold, remove the valley gasket to look at the rods, lifters and Cam lobes would be a start, as he indicates it is coming from under the Inlet Manifold....

My option would be to whip those items off and take a goosey....could be a duff follower bouncing around intermittently causing the slight engine rocking due to in-efficent valve opening times, but then it behaves and not ticking sound...then it looses internal hydraulic pressure, and bounces around again causing the ticking, until it pumps itself back up again.

This would be worse when the oil is cold and thicker, but getting better once it is warm.

When it happens under load my thoughts would be piston gudgeon pin bearings, the big ends or Crankshaft Bearings as the extra load would cause the knocking to become worse due to the extra force these components will have to stand up to. Usually (I could be wrong) the camshaft, lifters and valves don't have anywhere as much force applied during load conditions, so if it is worse under load, it is time to look at what is stressed during this time, which would be Pistons, Con Rods, Gudgeons, Big Ends, Crankshaft Bearings, Liners etc....

But the OP seems to not want to strip a duff engine due to it being a waste of time (who would blame him - I sure wouldn't want to do that much work if it is only going to go to the scrapper in the sky anyway), but unless he has a pot of spare cash for a new engine/vehicle, the only option I can see is to get into the engine internals and see what is a miss, unfortunalty
Click to expand...


Yes but if it was crank piston related it would be sycronous with full engine speed, little ends do make a tinkling noise, if it was valve gear it would be syncornous with half engine speed. Only way as you say is to strip and look. How he expects a diagnosis from the description i do not know.
 
wammers said:
Yes but if it was crank piston related it would be sycronous with full engine speed, little ends do make a tinkling noise, if it was valve gear it would be syncornous with half engine speed. Only way as you say is to strip and look. How he expects a diagnosis from the description i do not know.
Click to expand...

To be fair he's probably just asking for likely issues from someone who knows this particular engine like the back of their hand.
 
wammers said:
To be honest my friend with your posted experience you should not have needed to ask the question. You should just have got on and sorted it. It's much the same as any other engine the crank goes round and the pistons go up and down the valves open and close. Repairing them is simplicity itself. Just get on and do it.
Click to expand...

It is just because of my experience that I ask the question. Indeed a complete disassembly/overhaul would bring the problem to light and fix. BUT this would be an overkill in all possibility. Tapping in the experience of the owners is always good practice.

Now that said, I had hardly any time for this this problem as I had to go abroad, but namaged to top up the halogen in the stop lights, no change
biggrin.gif
. Seriously, I managed to make a quick few movies thus recording the noise, sorry about the quality, had to do it with a phone but the sound is pretty accurate. The movies are on a site
Photography in Motion by Andre C. Hulstaert – Range Rover noise
for you all to hear.
The first one, the longest, is the engine idling. One can hear that the knocking or clapping noise is more or less in sync with the engine. This chages however as soon as the engine is revved, then it becomes erraric to sync again. It is also plain that it originates somewhere in the plenium at the left side in the vicinity of the throttle valve. When the valve cover is opened the noise does not get any louder more or less elimitating tappet or lifter noise.
In another movie the engine is under load (in gear with brakes on) and one car hear the the clapping get louder to extremely loud very rapidly.
Also there seems to be a reflux when one looks at the two little pieces of debris being sucked agains the gaze, they seem to be jumping up when loaded.
confused.gif

Keep you informed
 
Same - still no sound - can see the video's alright and all volume's are working with other video's just not these.
 
FIY I could see the videos with sound... And good lord this is scary! Sound like someone stuck in the engine is using an hammer to signal he/she is trapped inside the engine ;-)

PS I am on Mac running FireFox.
 
SpacePig said:
FIY I could see the videos with sound... And good lord this is scary! Sound like someone stuck in the engine is using an hammer to signal he/she is trapped inside the engine ;-)

PS I am on Mac running FireFox.
Click to expand...

I've tried everything now and just no sound, maybe out of sync:D
Got a wee trapped man in my engine too - sometimes he sleeps though, really like to hear these videos to compare:rolleyes:
Windows 7 on near new pc
 
Trapped Gremlin - Get it out ASAP;)

My guess is is in the tappet/pushrod/cam area - sounds like 1 of them only - Tappet not loading every time?
Bit like a valve not doing what it's supposed to do caused by activation failure - could be wrong though. (Safe-guarding here:))
 
The way that noise is travelling back up the inlet tract - sounds like an inlet valve stuck open or severely leaking to me. Compression test.
 
Sounds like a sticking valve. Possibly bent, compression test is needed. Valve sticks tappet loads up to take up slack piston bends valve.
 
You must log in or register to reply here.

Similar threads

RRf4n
Loud moaning noise when braking in reverse?
Replies
6
Views
702
Graculus
Graculus
ar1g3
P38A P38 rattle at idle
2
Replies
26
Views
3K
roythebus
R
Flossie
P38A Eas issues
2
Replies
22
Views
1K
Datatek
Datatek
C
Can anyone help?L322 td6 noise when releasing accelerator.
Replies
2
Views
405
cpdriley
C
S
Series 3 Loud knocking sound from the engine when running.
Replies
12
Views
345
steve2286w
steve2286w
Back
Top