Bad knock under load

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Take the oil filler cap off ( on the rocker cover ) does it sound louder?
To me it's tappets if that makes a difference - if a push rod was broken or a rocker then it would be really loud and obvious at tick over.
 
sausage said:
I had the same symptoms on a Datsun a series engine ,after a head gasket replacement similar noise ,I replaced the head gasket, retourqed and set clearances and never found any problems ,the noise was gone after the second go at it ,weird
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I didn't like the look of the BP head gasket tbh but I needed it quick and it was the only one on the shelf locally.

I did retorque the weekend after changing it, about a dozen startups and a 100 miles or so. It could be that but I think I'll pull the head and change it anyway for one not made of recycled chewing gum wrappers now I've resigned myself to being off the road for a bit.
 
Still do the pressure checks before the strip down just for piece of mind.
Check valve clearance with cover off
And make sure they are seated correctly.

As for been off the road for a bit is this not a 3 hour job? Once you have the parts of course. :)
 
Hicap phill said:
Still do the pressure checks before the strip down just for piece of mind.
Check valve clearance with cover off
And make sure they are seated correctly.

As for been off the road for a bit is this not a 3 hour job? Once you have the parts of course. :)
Click to expand...

If it's just a gasket change yes but I don't want to keep pulling it apart and putting it back together to see if anythings changed then having to pull it apart again so I'll keep going until I'm sure there isn't a deeper problem. I've ordered up a better quality head gasket but anything else needed will be have to be waited for.

I've got very little spare time ATM and am playing catch up at work, long days and weekends so it'll be bit by bit when I've got the chance.
 
blue beasty said:
If it's just a gasket change yes but I don't want to keep pulling it apart and putting it back together to see if anythings changed then having to pull it apart again so I'll keep going until I'm sure there isn't a deeper problem. I've ordered up a better quality head gasket but anything else needed will be have to be waited for.

I've got very little spare time ATM and am playing catch up at work, long days and weekends so it'll be bit by bit when I've got the chance.
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the only thing I have learnt over the years is if the problem wasn't there before - why has it come now? the issue may be staring you right in the face! the gasket change on the Nissan that was pointed out was also an issue fiat's ( late 70's early 80's)used to have when there was no dowels to line the gasket up with the block and if the slightest movement happened the piston used to his the fire ring on the gasket when revved - sounded like a big end!
 
Something like a washer didn't fall into one of the cylider said when the head was off, did it? Or something not tightened up properly. I think it's unlikely to be bearings if all was well before but it might be worth dropping the oil to see if anything is in it.

Col
 
Little end is more of a light tapping.

Big ends knock under load...but why would this noise only shows itself after a new mainifold gasket...

Nothing dropped inside an ex or inlet port by any chance???
 
blue beasty said:
Manifold gasket was changed after the noise appeared.
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Oh, sorry. I thought the noise had appeared after the gasket change. Could be almost anything then as previously said. The trouble with these noises is that they can sound like they are in one area of the engine but are actually somewhere else entirely. If nothing seems obvious after a new head gasket, I'd drop the sump and examine the big ends. And if your going to do that, it might be worth changing them anyway.

Col
 
could you have a leak between exhaust manifold and inlet so hot exhaust gases are mixing with in going petrol and air I had an early 2/14 that had this happen it was making noise that sounded sompthing like yours on earley engines there was a gasket between top of exhaust manifold and bottem of in let manifold and this had started to leak I don't know if later manifolds were like this
 
Hard to tell through laptop speakers, but are you sure it's not pinking/detonation as a previous poster suggested? Changed the timing by accident?
 
8ha said:
could you have a leak between exhaust manifold and inlet so hot exhaust gases are mixing with in going petrol and air I had an early 2/14 that had this happen it was making noise that sounded sompthing like yours on earley engines there was a gasket between top of exhaust manifold and bottem of in let manifold and this had started to leak I don't know if later manifolds were like this
Click to expand...

You mean where the manifolds bolt together? I've not seperate them, didn't realise there was a way for gases to escape between them.
 
blue beasty said:
Could be but seems to be on just one cylinder and I didn't do anything in the engine bay prior to it appearing.
Click to expand...

That's fairly conclusive. Just doesn't sound like either small or big ends that I've experienced, so my next guess is a broken valve spring and you're getting one valve tapping a piston.
 
It's a Land Rover. You should pray before further investigation. The correct course of action should be church Sunday morning, spannering Sunday afternoon, revising the workshop manual Sunday evening.
 
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