Tapping/clicking noise that changes with rpm

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MarkBee

New Member
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5
Location
Honiton
I'm after some help with a noise in my SWB series 3 Landrover please.

THE NOISE
It's like a tapping/clicking noise that changes with rpm, particularly when under load. It almost disappears when I take my foot off the accelerator, or just ticking over. It sounds like it might be coming from the back of the engine.

BACKGROUND
I recently had a blown head gasket, but the noise was present before then. I replaced the head gasket, and manifold gasket, and set the valve clearances. The engine ran rough, so I checked the timing. The mark was so far to the left it took me a while to find it. I eventually found the vacuum on the distributor was faulty, and when replacing it didn't solve the problem, investigated further and found a spring was broken on the weights in the bottom of the distributor. I replaced the whole distributor (electronic points). If I correctly set the timing to the correct mark, the engine runs really rough, it runs best when the mark is at the top of the flywheel (about 15-20 degrees BTDC!) if I set the points correctly, it runs rough and I still get the noise.

Today I have replaced the diaphragm in the pcv valve and reconnected the pipe to the crankcase, after being blocked off for a long time and re-checked the timing. I mention this in case it's relevant, but it made little difference.

I have checked and re-check the valve clearances; engine hot and cold.

Any help would much appreciated.
 
Last edited:
Maybe a worn cam follower. I replaced my points with an electronic module in the existing distributer. I didn't think electronic distributers had any points to set. When you checked the tappet settings, did you notice that any of the threaded section of the adjustment screws were protruding noticeably more than the others?

Col
 
I didn’t notice any of the adjustment screws protruding more than any others, but I wasn’t particularly paying attention, so I might take a look.

I’ve checked and re-checked the valve clearances.

I’ve really played around a lot with the timing. It is very advanced because that is where it seems to run best, but I still get the noise when set correctly. I’ve read that having an electronic module in the distributor may require the timing to be more advanced?
I’m not experienced ‘pinking’ but I didn’t expect it to sound like this...more of a tapping/clicking noise.
 
MarkBee said:
I'm after some help with a noise in my SWB series 3 Landrover please.

THE NOISE
It's like a tapping/clicking noise that changes with rpm, particularly when under load. It almost disappears when I take my foot off the accelerator, or just ticking over. It sounds like it might be coming from the back of the engine.

BACKGROUND
I recently had a blown head gasket, but the noise was present before then. I replaced the head gasket, and manifold gasket, and set the valve clearances. The engine ran rough, so I checked the timing. The mark was so far to the left it took me a while to find it. I eventually found the vacuum on the distributor was faulty, and when replacing it didn't solve the problem, investigated further and found a spring was broken on the weights in the bottom of the distributor. I replaced the whole distributor (electronic points). If I correctly set the timing to the correct mark, the engine runs really rough, it runs best when the mark is at the top of the flywheel (about 15-20 degrees ATDC!) if I set the points correctly, it runs rough and I still get the noise.

Today I have replaced the diaphragm in the pcv valve and reconnected the pipe to the crankcase, after being blocked off for a long time and re-checked the timing. I mention this in case it's relevant, but it made little difference.

I have checked and re-check the valve clearances; engine hot and cold.

Any help would much appreciated.
Click to expand...

I too would be most interested to know the cause of this noise because it sounds like exactly the same as my 2.25 petrol. No noise when idling except the tappetty click but when driving under acceleration its really loud but when you back the throttle of it just about disappears. So if anybody has any ideas what it might be I'd appreciate it.....it does sound like its right behind the bulkhead and definitely from the engine.
 
Are you sure the dizzy is in the right place to start with ?

Has the head been modded for unleaded ?

If you set static timing to 6 BTDC... and fiddle with that, what happens ? It may be nearer to 4 or 5 BTDC with decent iggy ...
 
Its a 1978 ex mod petrol so assuming its not an unleaded head. The noise is there wherever the distributor is set to, I did the setting by ear and got the best engine performance I could like that as got no strobe.
 
I have a 2.25 L petrol and get a similar sound. To me, my engione sounds like it is clattering. Machine-gun like, and occurs only at the top of the revs just before changing gears. At the top of 2nd, at the top of 3rd, and even when accelerating in 4th before I change to overdrive. When driving at a moderate pace for the gear I am in, I do not hear the sound at all - like 25mph in 4th gear. All is fine.

If I am in idle, and I rev the engine, I do not hear the clattering sound. I only hear clattering build up louder as I reach the top revs for a gear I'm in and it stops as soon as I shift up.

Is this the same sound you are describing?
If not- any ideas here?
Thanks!
Mike
 
If I've understood the symptoms correctly you have a noise that is mainly load / rev dependant. Valve train has no idea what load the engine is under, all it knows is revs. I would be looking at the exhaust system and manifold, sound like a blowing gasket to me. Of course the exhaust is one of only a number of things that respond to load, could be big ends, could be the head gasket again and as other have pointed out could be pre ignition, just massively retard the ignition should to try and eliminate it from the equation.
 
ObiWanKenobi said:
I have a 2.25 L petrol and get a similar sound. To me, my engione sounds like it is clattering. Machine-gun like, and occurs only at the top of the revs just before changing gears. At the top of 2nd, at the top of 3rd, and even when accelerating in 4th before I change to overdrive. When driving at a moderate pace for the gear I am in, I do not hear the sound at all - like 25mph in 4th gear. All is fine.

If I am in idle, and I rev the engine, I do not hear the clattering sound. I only hear clattering build up louder as I reach the top revs for a gear I'm in and it stops as soon as I shift up.

Is this the same sound you are describing?
If not- any ideas here?
Thanks!
Mike
Click to expand...

Definitely gets louder as the revs /load build up.
 
Kane -
Thanks for this advice in what direction to go. Based on my description could it also be my engine bearings or rod knock, something like that? If the answer is a gasket, that would be really great. Will try the timing first, then look at exhaust.
Thanks!
Mike
 
How worn is the engine? If its little ends or piston slap then best bet is a bit more soundproofing and turn the radio up (or as its a series, get a radio!)
 
Thank you so much for you replies.

I have since re-checked the valve clearances (all good, as are the spark plugs). I have very recently changed the head gasket, manifold gasket, and distributor. However, the noise was present before changing these.

Today I re-checked the timing with a strobe light. The engine runs best at idle when the notch is at the top of the fly wheel (>20 BTDC), but today I set to about 9-10 BTDC. This was a happy compromise between where it sounded best and where I think it should be at 6 BTDC. The noise was still there. It actually runs ok, with power, and no spluttering. I'd be quite happy with the performance if it wasn't for the noise. It doesn't really matter where I set the timing, I still get the noise....so have I eliminated the timing/ignition as the issue?

It's difficult to describe the sound, but probably 'clacking' is as good as anything. It's hard to detect at idle, but can just about hear it. It's at its loudest when under load (pulling away, accelerating, or going up hill). It changes its speed with the gears/revs. If I put my foot on the clutch and rev the engine I can hear it (but fainter), but I can't hear it when free-wheeling. When stationary the sound is more probably more prominent at the back of the engine (but it Is hard to pin-point).

Do you think it might be the timing belt, stretched and needs replacing or tensioning? Are there any other tests I can do to narrow down the search/diagnose the problem. Thank you. Any help really appreciated.
 
The timing chain is at the front of the engine though, if it was that, I would think it would be easier to distinguish. Maybe a cam follower has worn badly near the back of the engine. One of mine is worn I think because the adjuster for one of the valves has more thread showing than the rest and I can hear a clacking sound sometimes under load too. At some point, I aim to change the head for an unleaded type, when I eventually do this I will change the cam followers too.

Col
 
Blag a stethoscope or use a long screwdriver or extension bar, put it to your ear bone, the lump behind your ear .. it may help to pinpoint the noise better ...
 
Colthebrummie said:
The timing chain is at the front of the engine though, if it was that, I would think it would be easier to distinguish. Maybe a cam follower has worn badly near the back of the engine. One of mine is worn I think because the adjuster for one of the valves has more thread showing than the rest and I can hear a clacking sound sometimes under load too. At some point, I aim to change the head for an unleaded type, when I eventually do this I will change the cam followers too.

Col
Click to expand...

Thank-you all for your help, I feel like I am narrowing down on the problem.

I took another look at the adjusters today. The adjuster for number 8 valve Actually has less (not more) thread showing than all the other adjusters. The noise also seems to be coming from the back of the engine (I haven't listened with a stethoscope yet @Dippypud), so might indicate something?

This is the opposite to what you suggested @Colthebrummie (less thread rather than more), so not sure what this signifies. Do you think this is enough to start investigating the cam followers or would that be a bit hasty?
 
MarkBee said:
Thank-you all for your help, I feel like I am narrowing down on the problem.

I took another look at the adjusters today. The adjuster for number 8 valve Actually has less (not more) thread showing than all the other adjusters. The noise also seems to be coming from the back of the engine (I haven't listened with a stethoscope yet @Dippypud), so might indicate something?

This is the opposite to what you suggested @Colthebrummie (less thread rather than more), so not sure what this signifies. Do you think this is enough to start investigating the cam followers or would that be a bit hasty?
Click to expand...
that would show rod is bent or follower worn or rod pushing through the brass follower
 
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