Engine Knocking!!

[jeboa]

All,

Can anyone give me a quick starting point on a sudden engine noise?

Link to Youtube recording of noise

Got back from the Growl today (great weekend - thanks to everyone), parked the car up - everything fine - went out for a quick spin about an hour later - and this noise started suddenly about 10 minutes in.

Sounds like it is coming from the mid/bottom end of the engine - initially thought it might have been the water pump (optimistic), so ran it quickly with the belt off - and still the same noise.

Sounds like a severe knocking. Have tried pulling the spark leads off one by one to see if it may be related to a particular cylinder - but no difference.

Not sure where to start, but suspect it could be cam related (bearings?) main bearings, or big end bearings? When turning over with the starter the knocking doesn't seem to be there, but as soon as it fires up it is very audible.

[5.0ltr]

Martin, good to meet at Growl. Sorry to hear of this issue and difficult to say from the video, however it does seem that the noise is in time with the V belt shuddering? Perhaps a pulley bearing? But as I said hard from the video and hopefully an easy fix.

[jeboa]

Thanks Bob, good to meet you to.

Unfortunately I don't think it's related to the water pump/alternator as the sound is the same with the belt removed.

Going to drop the sump this week to see if I can detect any problems with the main/big end bearings. Sounds a bit like piston slap, but thought you only usually get that under load. I think I may also pick up a compression tester tomorrow as well.

[chris52]

How's the oil pressure?
I would start off with top end first checking that a rocker hasn't come loose or lost a tip also push rods can bend and start slapping the head.
Difficult to tel from the video but to me the sound doesn't seem deep enough for a big/main bearing.
Chris

[Vixpy1]

Sounds top endy, I would pull the plugs and have a look in the bores

[Alexdaredevilz]

Pull the rocker covers off, I think there is some thing a miss in there

Almost sounds like there's a spark plug missing

[TVR Beaver]

Others always say it but I never have... but to me, from the vid... it sounds like an exhaust gasket blowing??.. hope it is

[griffdude]

Yup I'd go with an exhaust manifold initially (best case too). Tube to ear then poked about next to the engine should help to pin point the noise.

[haircutmike]

£5.00 on an exhaust gasket, no £6.00!

[jeboa]

Quick update:

1. Checked the spark plugs - and one was loose - but still there, tightened up - smae noise.
2. Oil pressure was fine.
3. Pulled the rocker covers off to check everything is okay in there, looks to be okay - all pads are in place and the push rods don't appear to be bent.
4.Checked the exhaust manifolds - all nice and tight (have used Nordlocks on these, which seem to be pretty good so far).

I think the Youtube video sound may be a little misleading - the knocking is deeper, but I think maybe the phone microphone doesn't pick it up that well.

Now the car has cooled down, the noise is a lot louder as well.

Drained the oil and am going to pull the sump off tomorrow to have a look.

Thank you for the advice so far, any ideas or pointers more than welcome.

Edited by jeboa on Sunday 10th June 20:45

Edited by jeboa on Sunday 10th June 20:46

[haircutmike]

Don't bother with the sump, check the head to manifold joints with a length of hose in your ear, bound to be the exhuast gasket.

[The AJP Griff]

haircutmike said:

Don't bother with the sump, check the head to manifold joints with a length of hose in your ear, bound to be the exhuast gasket.

^^^^^^^
What he said.
I'd look at the exhaust gaskets first as well. When I had the bottom end bearings go on my Chim it didnt sound anything like that and if oil pressure is fine thats another good sign(mine was low),so do the easiest first. When its stone cold,hold some tissue around the manifold joints to see if it gets blown about by any escaping gasses which would indicate where it's coming from.

[SSPPGG]

definately sounds like gaskets on the vid

[Ant.]

jeboa said:

Quick update:

1. Checked the spark plugs - and one was loose - but still there, tightened up - smae noise.
2. Oil pressure was fine.
3. Pulled the rocker covers off to check everything is okay in there, looks to be okay - all pads are in place and the push rods don't appear to be bent.
4.Checked the exhaust manifolds - all nice and tight (have used Nordlocks on these, which seem to be pretty good so far).

I think the Youtube video sound may be a little misleading - the knocking is deeper, but I think maybe the phone microphone doesn't pick it up that well.

Now the car has cooled down, the noise is a lot louder as well.

Drained the oil and am going to pull the sump off tomorrow to have a look.

Thank you for the advice so far, any ideas or pointers more than welcome.

Edited by jeboa on Sunday 10th June 20:45

Edited by jeboa on Sunday 10th June 20:46

Let it cool over night and see if the knock is still there in the morning.

I hope I am wrong, but if the knock is a deeper tone than the vid suggests, it sounds like mine did when a liner came loose.

My engine went from fine to heavy knock between J24 of the M1 to pulling off at J31.

Hopefully in the morning the noise will still be there at startup which indicates it is NOT a liner loose.

[pwd95]

Exactly like my old 450 Wedge. The head gasket blew out the side...............



Good luck.

[red griff roger]

I'd go for exhaust gasket too. use a bit of garden hose in your ear and probe around the joints.

[jeboa]

Dropped the sump off this afternoon - looks like bad news!

Some large pieces of metal (5-10mm long), and what appears to be a metallic paste when you rub it between your fingers. There's quite a lot of smaller pieces in the main part of the sump.



Also noticed something that seems unusual - two of the big ends seem to be 'polished' on the sides. I thought this may have been intentional (for close tolerance, or something) - but it looks as if the wear has extended to the bolt, so this must have happened in place. You can see one of the normal casting marks in the photos below - there is a small 'rib' running down the side, this has been worn away on two of the big ends.

Edited by jeboa on Wednesday 13th June 19:35

[D_G]

Big end bearing failure then. The polished bit you are seeing is where the bearing has been pounded flat and come out of the gap.

Rebuild time I'm afraid...

[The AJP Griff]

D_G said:

Big end bearing failure then. The polished bit you are seeing is where the bearing has been pounded flat and come out of the gap.

Rebuild time I'm afraid...

Not quite rebuild time necesarily. When mine were shot it was a pretty straighforward job done with the engine in situ,obviously the crank needs to be unscored/worn.The sump was removed and both mains and big ends changed without even removing the crank. If compression is good and youre not burning oil or have any other issues justifying a rebuild then it's not at all expensive to replace both sets of shells.

[D_G]

The AJP Griff said:

Not quite rebuild time necesarily. When mine were shot it was a pretty straighforward job done with the engine in situ,obviously the crank needs to be unscored/worn.The sump was removed and both mains and big ends changed without even removing the crank. If compression is good and youre not burning oil or have any other issues justifying a rebuild then it's not at all expensive to replace both sets of shells.

Did yours fail as badly as in this engine? I'm not familiar with these engines, can you check the journals properly in situ? I'd not be comfortable if not as you are setting yourself up for another early failure, that's without the debris that's spread around the oil system.
Proper repair is engine out and proper rebuild IMO.