P38 4.6 videoed loud banging noise when driving.

Ok flex plate looks ok. Can't see any cracks etc.

Marks on the torque converter could be old. Nothing in the bell housing loose anyway.

New v fan clutch and water pump fitted today. Wobble has gone on the fan. But knocking noise still there.

Managed to stethoscope the engine and appears knocking noise coming from the passenger side of engine. Can hear it in the plenum chamber and on block just above the exhaust manifold.

Lazylabs said:

Ok flex plate looks ok. Can't see any cracks etc.

Marks on the torque converter could be old. Nothing in the bell housing loose anyway.

New v fan clutch and water pump fitted today. Wobble has gone on the fan. But knocking noise still there.

Managed to stethoscope the engine and appears knocking noise coming from the passenger side of engine. Can hear it in the plenum chamber and on block just above the exhaust manifold.

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Loose liner?

I'm not loosing any coolant and no oil in coolant and not overheating.

Engine oil looks clean.

Will try compression test today see if any issues show up from that. What sort of compression should I be getting?

Lift the rocker covers and check for a Broken rocker

Well its in with local LR specialist now. Their initial thought is it's a misfire, caused by what they are not sure. There is a cracking noise coming from the passenger side of the engine when you blip the throttle when car is stationary. This is the noise I heard.

Currently the following has been checked:
New v Fan Clutch and water pump fitted prior to going to garage. (Wobble found on v fan has now gone.)
No fault codes showing for any system (small smile here as I like that... hard work over the pass 6 months to clear all the codes)
Rocker cover removed and rockers and valves checked.
Exhaust system removed piece by piece and checked.
Compression test performed and all same values and ok.
Plugs and leads tested.
Coil packs tested and all ok.
Injectors checked and all working ok.

So electrically it all appears ok, and initial check of rockers and valves from the rocker cover didn't reveal anything, certainly nothing broken or obviously sticking.

Next step is inlet manifold off and inspect the camshaft and followers etc.. awaiting results.

It sounds almost as if there is a hole in the exhaust manifold gasket or a valve is sticking. Will be interesting to see what it is.

Yes looking forward to seeing the answer. Hope it's nothing too major!

Grrrrrr said:

It sounds almost as if there is a hole in the exhaust manifold gasket or a valve is sticking. Will be interesting to see what it is.

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+1 cracked manifold or manifold gasket failed/failing

wil2813 said:

+1 cracked manifold or manifold gasket failed/failing

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Let's hope , cheapish fix.

Seeing as it was OK before the cats were replaced and only started after they were fitted my bets on a cracked manifold

Well the puzzle continues.

Inlet manifold off, camshaft, followers, valves all check as much as possible and all good. No
Cylinders pressure tested to to point where the engine try's to turn over and no problems.

Next options is either possible timing issue so front engine strip down and inspect or heads off and inspect lower engine further.....

Lazylabs said:

Well the puzzle continues.

Inlet manifold off, camshaft, followers, valves all check as much as possible and all good. No
Cylinders pressure tested to to point where the engine try's to turn over and no problems.

Next options is either possible timing issue so front engine strip down and inspect or heads off and inspect lower engine further.....

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exhaust manifold not inlet

wil2813 said:

exhaust manifold not inlet

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+1 or gasket

Exhaust manifolds all checked, gaskets are new. Nothing blowing..

One head is currently off.. possible exhaust values not been seating properly.. anyway in for a penny in for a bloody lot... other head coming off this afternoon.

Well the results are in.

Camshaft has had it. Looks like oil starvation. Blacken around number 2. Looks like been dumping fuel and not enough air.

Going to see it tomorrow.

So new camshaft and followers etc.

What shall I put in? Stock? Upgraded high torque?

Lazylabs said:

Well the results are in.

Camshaft has had it. Looks like oil starvation. Blacken around number 2. Looks like been dumping fuel and not enough air.

Going to see it tomorrow.

So new camshaft and followers etc.

What shall I put in? Stock? Upgraded high torque?

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Personally stock, anything hotter may knock the bottom end out.

Lazylabs said:

Well the results are in.

Camshaft has had it. Looks like oil starvation. Blacken around number 2. Looks like been dumping fuel and not enough air.

Going to see it tomorrow.

So new camshaft and followers etc.

What shall I put in? Stock? Upgraded high torque?

Click to expand...

imo id also be looking close at oil pump condition,filter,oil grade,oil ways etc etc

wil2813 said:

imo id also be looking close at oil pump condition,filter,oil grade,oil ways etc etc

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Tear it out and full recon is the best way to be sure. liked atcha Wil

What full recon engine?

I'm going down to see it tomorrow and discuss way forward.

Looks like the oil feed on number 2 is blocked up or has been. That's where the worst part is. Couple of worn followers.

Good news is the rest of the engine is looking ok. Pressure and seal wise.

Expensive job but once complete I have sorted the cooling system and all other systems are working well. It's a good job I like this car!

If the cam is gone, check the bigends and also the cam bearing shells take a beating if the cam lobes are shot...

Also if there is little oil getting to the cam, the rockers and shafts are gone more than likely.

In essence, I'd reshell the whole engine and any other part in contact with oil!

Sometimes I wish I had persisted more with my 4.0 P38, but at the time and a 9 month old baby, 2 Range Rovers was a handful....