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Duncanincapable

Active Member
Over the weekend my son and I changed head gaskets and valve stem seals on the p38 4 litre range rover. Rebuilt and reconnected battery prayed to the land gods turned the key and she fired up ticking over sweet as a nut no leaks or hisses or smoke stood back pleased as punch when all of a sudden there was a pop and what sounded like a nut or something solid shoot down the exhaust.left it ticking over and it happened again has anyone experienced this or shed some light on what it maybe thanks.
 
a nut shooting down the exhaust ?

seriously though, for anything to exit the combustion chamber, there's only two ways it could have got in, 1, thought the intake.. then you'd have the noise of the pistons trying to compress something solid and losing, or it was in there went together.

If I were in your shoes, i'd do a compression test, or drop the cats out and find out what it was. to drop the cats off you'll need to remove the gearbox support, 4 bolts on either side and six in the middle and pry bar it out with a support under the gearbox.. or you pull it all apart again and have a look inside

I can only think something valve related on the exhaust valve ports like the stem seals ?

I did the HG's on my 4.6 this year and didn't touch the valves as they were in excellent shape. I cant think of anything between the cylinder and the exhaust that could move. best of luck and let us know what you find
 
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pete1987RRC said:
Exhaust gasket disintegrating?
Click to expand...

I shouldn't think so.. the exhaust gasket is metal and sandwiched between the manifold and the head, there's no overlap so I cant see it disintegrating in the first place and if it did break up with 40NM on the bolts they should be held in place
 
You can put them on upside down on a classic, this blocks half the exhaust port, can you do this on a p38 also.

What else could be rattling about?
 
It's just good practice,

Won't have given you your issue though, I just thought out loud before engaging brain.

A detached spring collet cannot find it's way into the cylinder, it's remnants would simply terminate atop the head under the rocker cover, maybe damaging a rocker arm.
Also it could fall down an oil drain channel to the sump, unlikely to hurt anything.
 
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Rust in the manifolds if they were lying about prier to fitting,, ,Or bits of piston rings:eek:,unburnt fuel popping in the exhaust :eek:......
 
dubbleRR said:
Rust in the manifolds if they were lying about prier to fitting,, ,Or bits of piston rings:eek:,unburnt fuel popping in the exhaust :eek:......
Click to expand...
Manifolds came off on Saturday put back on Sunday inspected bores and no signs of wear or pitting unburnt fuel is feasible did seem to be running slightly rich.how does one change the mixture without cars?
 
you cant change the mixture. its managed by the fuel ECU in a loop between the O2 sensors and MAF. if you have unburned fuel leaving the chambers the cats will glow red
 
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