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Discussion Starter #1
Hi all,
I must confess that I have not contributed to the Forum for ages, primarily because my high mileage ((350,000km) P38 4.6 HSE (1997) has been performing faultlessly for ages.
I have just returned from a boating trip towing my heavy yacht back from the Gippsland Lakes. The day was very hot. The engine cooling seems perfect. Very steep terrain.
I noted that although the engine starts well and runs smoothly without great oil consumption or smoking , it's power seems to be down. In fact on particularly steep hills it may be back by a gear and 20 km/hr. Fuel consumption, always heavy does not seem greatly worse, country driving without towing about 14.2lt/100 km, 21/100km heavy towing.
The reduction of power is more noticeable at lower revs. In deference to the cars high mileage I do not drive the car hard, keeping RPM below a max of 4000 even on the steepest hills. The reduction in power may have been occurring over some time but not noticeable as I was not towing.
The cars exhaust is burnt out which I will now replace. Filters etc are all clean. I have not compression tested it though it cranks smoothly.

Question!
What thoughts do readers have regarding the reduction in power, considering it's smooth and otherwise faultless running ?
Is it possible that it is suffering from cam wear (it is not mechanically noisy)?

Could the catalytic converter be collapsing?

I am considering removing the heads and inspecting and I am happy to have them reconditioned but I am loath to disturb an old motor that does not require it.
Can the sump be removed without removing the engine? I am happy to replace rings and bearings.

The problem is with the Rangey is that although I am supremely happy with it, is that it's very low monetary value means it would be easy to over capitalise it, not that I'm adverse to spending money on it.

Any thoughts or ideas greatly appreciated

regards
Alan
 

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So, assuming loss of performances means loss in horsepower....power....torque, etc? I had the same issue with my ‘99 P38. The issue: Blown head gasket that leaked enough oil into a couple cylinders to cause random misfiring which equaled a loss in power. A quick fault check with an ODBII reader will show if any cylinders have misfired. Aaaaannd, Bob’s your uncle.
 

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Discussion Starter #3
Thanks Tnovalis,
Does the 97 version of P38 have an ODB terminal?
I believe the engine is generally sound as it runs smoothly and other than lack of low down torque in all other ways it seems normal. It does not use coolant or oil, runs sweetly etc.
regards
Al
 

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Yes, all P38 models have an OBD connection although the GEMS isn't fully OBD compliant.

When my 98 got up to around 270,000 miles (430,000 kms) I also noticed it was down on power when towing. A compression test showed all cylinders down to about 110 psi, so the engine came out. I had the full works done to mine, top hat liners, big ends, mains, pistons, rings, cam, followers, etc and while the block was away I stripped the heads and gave them new guides and valves. I'm now at 370,000 miles (600,000 kms) and it still pulls like a train.

The sump can be removed with the engine in place (you need the suspension on high and maybe even jack the body up slightly to give clearance with the front axle). so rings and bottom end bearings can be replaced once the heads are off (don't forget to hone the bores while the pistons are out to bust the glaze). I'd suggest checking the cam but unless it is worn, leave it and you'll probably find that the valve heads have a build up of carbon on them from worn valve stem seals. Clean them up, lap the valve seats and fit new seals and you should find a noticeable difference. Your costs aren't going to be huge. Valve stem seals come with a head gasket set, so the only other costs are going to be the rings and bearings (and a few days work). I would recommend spending the extra on a stud kit for the heads rather than using stretch bolts, you've no idea how good or otherwise aftermarket ones are.
 

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it sounds like a worn fuel pump just check the pressure at the fuel rail , there is a shrader valve on the rail just use a tyre pressure gauge , it should read 38 psi give or take a psi.
 

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I'd start by checking the timing chain. If it's in there for more than 100k km, it will have stretched and timing will be off. Not expensive and not hard to replace. Some camshaft wear is to be expected as well. Unless a compression test shows low values on one or more cylinders, I's leave the heads in place.

Filip
 

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JACK'S GRANDAD
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Start with the easiest of tests, fuel pressure. Get an actual fuel pressure gauge and compare readings to RAVE.
Next pull the plugs and check compression and leak down.

Yes the camshafts wear. In fact I have never rebuilt a 4.6 WITHOUT a worn camshaft. They all ran, and ran relatively well, just down on power between the cam and timing set.

I'd certainly NOT go pulling the heads without firm proof they needed to be pulled. As far as that goes, it takes @3.5hrs to pull the whole motor out, so go that way if it needs a refresh
 

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Discussion Starter #8
Hi all
Thank you for the thoughts so far.
I have initially tested the fuel pressure and unfortunately discovered it was perfectly normal.
At this stage my most likely guess is a collapsing camshaft though I am keeping an open mind.
I must assume that the engine is untouched in it's 360,000 km life.
As previously mentioned it starts and runs perfectly, no missing or roughness, idles well, does not smoke or use oil or coolant. The primary issue is noticeable lack of torque at the bottom end and the this problem seems to be increasing..
Questions!
How much difference would a stretched cam chain make?
Could a catalytic converter have internally collapsed causing an exhaust blockage?
If the camshaft is removed with the engine in situ can the air conditioning condenser stay in place or does the system have to be de -gassed and the condenser removed?
I have seen a complete cam shaft kit for sale on eBay with a high torque cam, all lifters, timing chain etc. Are these worth the money ( towing is the vehicles primary purpose)?
Do the hydraulic lifters have to be shimmed, is it tricky?
Is there after market exhaust system, what is the best way to replace the exhaust ( OEM, have bits made etc)?
in assistance or thoughts greatly appreciated
with thanks Al
 

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JACK'S GRANDAD
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A worn camshaft makes sense. Gradual loss of power with no noticeable problems otherwise.
A stretched chain will also lose performance the same way, gradually with no outright problems.
A clogged cat would result in it not wanting to rev out. I had a rig a while back that would not rev out past @3k IIRC. disconnected the Y pipe and problem solved. New exhaust from the Y pipe back and it was sorted. You could disconnect the Y pipe and check, easy and free.
I always use Crower camshaft kits. Never had a single issue and they flat out work. No need to shim lifters etc. Check the pushrods for being dead straight and put it all together.
Never done a cam while the engine is in, but a quick search will answer your question.
I always run the OEM style exhaust, made at a local exhaust shop. Even with my current LS motor cranking out 385hp, a "normal" exhaust works just fine

Martin
 

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Yes, you can replace the cam with the engine and condenser in the car. You do need to take out the rad and loosen the rad mounts, so you can move and tilt the condenser and oil coolers out of the way (only just) to get the cam out and in again. I always use the high torque kit from Piper or Kent. The come with tappets, timing, seals etc and are very good value for money.

If you want to check the chain, you can do so by removing the sump and pushing it with a screwdriver. If it's floppy, just changing the chain will make a big difference. But chances are the cam is worn as well, so you could take it one step further, depending on time available.

Filip
 

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LEGACY VENDOR
1995-2002 Range Rover P38A
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I put a higher torque cam in the new engine I built for mine (it's my only vehicle and I discovered leaky core plugs - so decided to build a new engine and swap it in, rather than pull the old one out and rebuild).

I used a Piper Torquemax cam kit which I got here in the UK, and I must say the difference is noticeable - around 2000 rpm, you can definitely feel it starting to pull unlike the old one!
 

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With what I have seen here 100% Camshaft wear, but most noticeable on inspection will be the lifters (your camshaft lobes are worn away)
You can check it out with a 20-30 minute inspection
Take drivers side rocker cover off and look down through the pushrod shaft to the cam check second last cylinder.
Drop one of the tappets or two and pull a lifter up you will see that the base is concave and not convex, its just fair wear and tare after the milage.
Im running 360,000km I quite like the way it runs in this state, its like the engine just knows what it has to do, I drive it very easy hardly ever go over 2800rpm, it runs like a clock.
But yes towing will be a bit of a effort for the old girl, I hauled a series 2 back to Sydney from Bathurst 3 years ago Mt Victoria saw me crawling at 10-15km/hr, I was starting to think I was going to need low range, but she made it and is still on the road, ive had the old beastie for 19 years love the old girl its the best car I have ever had, still drives like a champ.
Agree its not even worth selling, I cant believe such a good car is so cheap.
Best advice for these engines, dont use and of the BS synthetic oils, its crap, you need Penrite 20/60 with extra zinc.
Let us know if you pull the cam and lifters, Im looking at doing it myself.
 

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have you done a compression test , if it had worn lobes etc it would be noisy, top end rattles? it might just be tired .
 

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Discussion Starter #14
Thank you Mad As and Best 4by4
i have not conducted a compression test but I certainly will. I will post the results.
The motor does not rattle however I imagine if only lobe wear is present rather than tappet wear it may not rattle.
The problem is only really noticeable towing. Now alerted to the problem I can recognise it in normal driving in steep country.
Best 4by4 mentioned speed back to 15km/hr towing a vehicle trailer up Mt Victoria. I imagine a 4.6 in good nick should have been able to haul it up that grade at quite a good speed. For those not familiar, Mt Victoria is the grade climbing up the western side of the Blue Mountains ( Great Dividing Range) towards Sydney from the West. Back in my childhood (60s) it was often quoted by 'Oldies' as the test of a good car, a Valient or similar could 'pull it' in top gear. Nowadays, with roadwork improvements, even my 'classic car', a 3lt 65 Humber Imperial can just about get it in top gear with a speed of about 80 km/hr at the slowest, perhaps a reflection of it's rather low gear ratio than stump pulling torque. I only mention it to reinforce the fact that I thought a Rangey even with heavy trailer shouldn't have too much trouble. I suspect your RR and mine are suffering a similar power loss.
My previous tow car ( still around) is a 3.2 Sangyong Musso. It has miles of power providing it is allowed to rev although the RR is a much more competent tow vehicle.
In good nick how does our vehicle's performance compare to the ubiquitous Land Cruiser diesel V8 that is the now the 'gold standard' for the caravan brigade? My interest is primarily to let me know what our vehicles should be capable of and how much torque I have lost. As I have said in previous posts I am not adverse to spending money on the old girl but I am loath to pull something apart without good cause. If it ain't ( too) broke don't fix it ;)
regards
Al
 

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Discussion Starter #15
Best 4by4
what do you mean by 'drop one or two of the tappets and pull up a lifter?
do you mean take the rockers off and remove a push rod? Can a tappet then be lifted out.
Although not unfamiliar with engines the last time I played with a Rover engine was my father's P6 circa 1976 as a kid. My memory is rather vague ;)
any further information greatly appreciated.
Al
 

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JACK'S GRANDAD
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Yes you can mess around and pull a lifter. After pulling a valve cover off, the rocker arms, then pushrod. You can then lift out a lifter with a long magnetic tool.
Not worth it in my experience, as you'd already be a good ways into a cam swap at that point.
 

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with the last comments you made I am back to the fuel pump ,you need to test it under load just revving it in the drive is not a good assumption that the pump is running at its proper pressure . under load it can consume almost 2 litres of fuel per minute.
 

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You cant actually pull a lifter out without pulling the manifold at some risk, I guess, you can take a peak at one and then re insert it, I have done this and was pretty disturbed at the amount of wear that I saw.......but hey that was about 10,000k ago and its still running no undue noise and no burning oil, it just soldiers on
 
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