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My Discovery 2 had a serious problem


mshawari1

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Hi, 

after I was having low compression in cylinders 8 & 6 on my 4.6 discovery 2 ... I went for full engine rebuild... new: Rings, bearings, lifters, Sparks&wires, oil pump and high lift camshaft 53231.

I have the following issues since the first start till now ( ~ 1500 km):

- rough idle... The exhaust sounds crazy.
- oil turn to dark black very fast.
- high oil evaporation from pcv.
- multiple missfire on diagnostic.
- very high fuel consumption 30L/100km.

I have done a compression test for all cylinders and it was 150 psi +/- 5psi.

I've test the intake manifold for any leak by spilling some water.

Recently the back crank seal start to leak oil while I cancel the pcv and had an oil catch can!!

I've tried to make the spark plugs with narrow Gap but no effect.

What you think I should do??

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Sounds a bit like the rings didn't seat properly, to give that sort of crankcase pressure.

Also, high fuel consumption plus black oil sounds like you have a coolant temp sensor issue, this is very common, and will fuel it as though it is -30C if faulty.

 

 

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Who did the rebuild and which parts did they use? An experienced mechanic using genuine Land Rover parts or someone inexperienced in a shed using cheap Britpart bits?

It's clear at least one thing has been done badly, so who knows what else could be wrong?

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The black oil would be expected if a graphited assembly paste such as Graphogen had been used when building the engine. IMO this is a good thing, and I would expect to carry out an oil change after an initial 500 miles post rebuild in any case.

Although you say it was a full rebuild you don't mention whether the bores were honed, bored, or re-lined. I'm assuming the original pistons must have been used. If the bores weren't at least honed the new rings don't stand much chance of bedding in correctly, hence your high oil consumption.

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The rebuild was done in-house with help of experience mechanical engineer. The rebuild kit from victor REINZ expect one ring from britpart as we break it. Connection bearing was replaced. But other crank bearing was not changed since we didn't remove the block from the car ... No honing ... Old pistons used.

No smoke comes from the exhaust so far ... I feel some pressure from crank ventilation over the valves cover

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Okay guys ... Guide me to the inspection steps. I would like to check if the cam alignment if it is correct. I'm planning to remove the valves cover and check if the cylinder no.1 valves are fully closed at TDC . Will but a screwdriver into plug hole to know if its at TDC. What you think? 

Next will check the valves seals ... But how?

Any other suggestions?

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On 2/2/2019 at 10:19 PM, Bowie69 said:

So new rings but no honing? Reckon you have found your problem....

 

 

Update ... 

There is small carnk case pressure.

I've visited two specialist:

The first one said it's due to slight miss alignment of the camshaft. But I can't see any indication of that.

Second one said it's due to wrong installation of ring with two cases .. a) flipped top ring, b) broken ring during the fitting.


What you think?

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  • 2 weeks later...

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