Renewing the Camshaft 4.0 V8

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y gwir

New Member
Posts
20
Location
Rhyl, North Wales.
My 2003 Discovery has started tapping, it only happens once the engine is warm but is really loud, sounds awful and bloody annoying. the car has only covered 81,000 full Landrover service history up to 65,000 and oil and filter changed by me every 3,000 miles since.

I've decided I'm going to replace the camshaft for a piper cam, renew the followers, pushrods and rockers in the hope that this will cure the problem.

my question is whether or not I will be able to replace the camshaft with the engine in the car or will I have to remove it to do this job.

thanks.
 
The little cups/pads can come loose on rocker arms and make tapping noises as well so I'd pull the covers off and have a look before splashing out on cams as well...
 
3.5disco said:
You 100% sure its not a manifold gasket?
Click to expand...

I wish it was, but no, I don't think it is. It's deffinately a mechanical tapp/knock. I've taken it to a few garages and the diagnosis ranges from sticking hydraulic lifter to worn lobe. RPI even suggested it was a loose liner but I think I will take a chance on renewing the camshaft, timing chain and lifters before I go to the expense of a new engine, especially as it runs quite cool and never uses coolant.
 
Cracked manifolds/gaskets can sound very metallicy... I'd have a listen through a hose. Any black soot is a dead give away. If no luck then I'd pull the cover and check the rocker arms.

I just did the tappets on my 3.5 and it wasn't that hard a job (ended up returning the cam because my existing one is like new- might get slated for that but I got away with it!). I could feel the bad tappet when I pulled the pushrods slightly- each of the pushrods moved up & down smoothly except for one which felt loose/disconnected

I slipped a liner in a 4.0 P38 I had and it was pretty conclusive- I was going up a hill, gauge suddenly went into the red zone, pulled over and there was NO coolant left at all!
 
Shagg-d cam and lifters tap when cold,if its only when hot I'd just go for rockers and shafts first - lot less trouble,and much more likely to sort it.
 
Update on the tapping noise. I decided to strip the engine today and have found nothing obvious. Rockers and shafts seem fine, engine is clean inside with no sludge or black build up. Followers are in mint condition as are the cam lobes. The only cause for concern is the fact that the inlet manifold bolts were all hand tight, I didn't need the ratchet to undo them, just used the extension bar and socket.

I have only inspected the cam through the gaps and haven't removed it, nor have I yet removed the timing cover. I really don't know where to go from here and am really reluctant to put the engine back together with all the expense involved in buying new gaskets having not found the problem.

Any advice of what else to look for would be really appreciated.
 
I'm wondering the same! But it was deffinately a heavy metalic tapping noise. I'm by no means an experienced mechanic, I'm just quite handy with a spanner, maybe the rockers are worn but not noticable with the nake eye. It's just that everything seems so clean, Ok, everything is a brown tarnished colour but no sign of black carbon deposits or sludge. Tappets are all perfectly flat and don't appear to have any wear in them at all. Is it possible that one of the tappets is not working correctly, ie not adjusting as it should for the wear. Is there any way of checking for this? I also see on the RPI website that you can't change the tappets without replacing the cam anyway. I'll be honest, funds aren't unlimited at the moment and I fear that having gone this far i'm going to have to pull the engine out and put a new short block in it, something I don't want to do and can't really afford.
 
a blowing exhaust manifold gasket or flange can sound just like a shagged cam rattlin onna v8 engine,sounds worse as yer guss faster anurl,why dint yer try wot was first posted it dint cost nuffin an mitta sorted yer out
 
yup thems really expensive them full head gasket sets :doh:

20 quid a cheap un 40 quid a dear un unless ya wanna go genuine bits :eek:










mind it wudda bin cheaper ta titen yer exhaust nuts up fust:D
 
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oil dripper said:
a blowing exhaust manifold gasket or flange can sound just like a shagged cam rattlin onna v8 engine,sounds worse as yer guss faster anurl,why dint yer try wot was first posted it dint cost nuffin an mitta sorted yer out
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I did check out what was first posted, Exhaust manifolds were fine. It's the inlet manifold which was loose. you probably know, but on the Thor set up, it's by no means a 2 minute job to check the inlet gasket or bolt tension. By the time you strip everything down to that stage, it makes sense to remove the two. 13mm bolts and slide out the tappets while you're at it.
 
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y gwir said:
I did check out what was first posted, Exhaust manifolds were fine. It's the inlet manifold which was loose. you probably know, but on the Thor set up, it's by no means a 2 minute job to check the inlet gasket or bolt tension. By the time you strip everything down to that stage, it makes sense to remove the two. 13mm bolts and slide out the tappets while you're at it.
Click to expand...
thas true,looks like yer delvin further into it then :(
 
y gwir said:
Ok, everything is a brown tarnished colour but no sign of black carbon deposits or sludge.
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Hi there, have you checked RPI's site for useful info clicky- RPi Engineering - V8 Engines I've gotta check mine when I get back from holiday. It's a 1994 with 120 thou on the clock. Been running sweet but it's my first V8 so I'm still learning!:eek: I thought my 300 was a handful........:doh:Hope you get sorted.
DD
 
y gwir said:
Update on the tapping noise. I decided to strip the engine today and have found nothing obvious. Rockers and shafts seem fine, engine is clean inside with no sludge or black build up. Followers are in mint condition as are the cam lobes. The only cause for concern is the fact that the inlet manifold bolts were all hand tight, I didn't need the ratchet to undo them, just used the extension bar and socket.

I have only inspected the cam through the gaps and haven't removed it, nor have I yet removed the timing cover. I really don't know where to go from here and am really reluctant to put the engine back together with all the expense involved in buying new gaskets having not found the problem.

Any advice of what else to look for would be really appreciated.
Click to expand...

I know on how you feel, i have the same problem! But mines a Disco V8 3.9 EFI Sagem
My engine has done around 180,000 K’s, oil changed ever 5,000 k’s, light brown tarnish looking through the rocker cover, been ticking for about three months now.
Replaced manifoilds / exhaust as part of an upgrade I had already planned, new gaskets made sure they were the right way around etc.
Still ticking, only when HOT! Changed from mineral 20/50 to 10/40 semi-synthetic Castrol Magnatec oil, but before that gave the engine a good flush to remove any loose bits of carbon that might have trapped around the lifters etc.
It never ticks while it’s cold thou, what do you reckon valve gear, slapping around?
My local garage told me to use an additive, something called resolve, none too keen on chucking additives in the engine.
I also have a huge amount of carbon build up inside the exhaust, when you wipe the inside it falls off, even blows out soot at start-up even when you floor it the cloud of clag that comes out the back is visible more at night in car headlights.
It’s not burning oil, oil level never changes.
Any ideas?
 
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