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Discussion Starter · #1 ·
Hi all,
An update and few questions regarding the engine rebuild.
The engine is still in the car and I would like to keep it that way
To update people, the engine appears in reasonably condition with very worn bearings, good bore, good crank and good cam gear, on close inspection some of the oil control rings were stuck. So this very much explains the engine‘s symptoms of low oil pressure and moderate oil consumption.
The big issue now is how to stop the rebuild job growing like Topsy. I imagine that nothing more than a good clean up, rings, bearings, head refresh and timing chain would achieve 90% of restoring performance back to new, but do I stop there?
The engine rebuilder (I put considerable trust in him) that I spoke to tells me the pistons are showing wear with the piston bearing on the bore well up the skirt. Obviously a new set of pistons would make it a better job but considerably push up the costs (not that it is prohibitive). If replace the pistons I would have the option of installing high compression pistons.
# Do the HC pistons give noticeable increase in power and importantly, torque (towing)?
# Much fuel here is 95 octane. Is this suitable for high compression pistons?
# The cam gear looks in very good condition, should I consider fitting a Kent cam high torque cam or similar?
# Should any serious head work be done (porting, larger valves etc) ?
# Has anyone scene any serious improvement installing aftermarket engine management chips?

I really appreciate the great answers I get from this forum. Let me stress my much loved HSE is primarily to be used for towing and I’m not imagining putting huge miles on it. It will never be in perfect condition. I can live with some imperfections and I do want to keep an eye on costs.

regards
Al
 

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You get an extra 8kW with high compression which is a five percent increase and its all on top. High compression 95-96 RON, all info in RAVE or owners manual. Camshaft wear is said to be a common issue with Rover V8s, if the valves aren't opening properly it's going to affect your power output. Might be worth looking into.
 

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if you replace your pistons i would strongly advise a rebore . if you dont want to do that look for a second hand unit and compare the price . people who i know that have done half a rebuild end up doing the rest at a later date and pay twice for the work
PS if you are going to work on the rings on a day like today (cold) put them in the oven or sit them beside the heater for a couple of hours before you try and fit them, they are as brittle as glass in cold weather.
PSS if you dont want to spend to much money on it just do the bottom end and not the heads as the heads can be removed and done at a later date.
 

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I suspect the HC pistons you are being offered are actually 4.0 litre pistons as they have a smaller dish in the top, unless your engine is the LC version in the first place. 4.0 litre pistons will push it up to around 10.3:1 which is probably too high for normal 95 RON fuel, not a problem if you can get 98 RON or run on LPG (112 RON). At 423,000 miles my engine still has the original pistons. When it was rebuilt at 285k, the builder pointed out that it isn't worth replacing pistons unless they are badly worn (in which case the bores will be too so will also need doing), the rings do the work, the pistons are just a lump of metal to hold the rings in place. I've often heard people say camshafts wear but that isn't my experience. I've pulled quite a few engines apart and not found worn camshafts in any of them. Don't forget if you change the camshaft you'll need to change the followers too so that will push your costs up quite a bit too.

My advice is a new set of rings, new big end and main bearings, new oil pump, new cam chain and bolt it back together.
 

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Australian engines are LC engines (48D for GEMS), so the increase in CR will be to about 9.5:1 or similar to the EU spec HC engines. As Richard says, unless you want to embark on a fair bit of expense, new rings and bearings etc. and bolt her back up.
 

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I suspect the HC pistons you are being offered are actually 4.0 litre pistons as they have a smaller dish in the top, unless your engine is the LC version in the first place. 4.0 litre pistons will push it up to around 10.3:1 which is probably too high for normal 95 RON fuel, not a problem if you can get 98 RON or run on LPG (112 RON). At 423,000 miles my engine still has the original pistons. When it was rebuilt at 285k, the builder pointed out that it isn't worth replacing pistons unless they are badly worn (in which case the bores will be too so will also need doing), the rings do the work, the pistons are just a lump of metal to hold the rings in place. I've often heard people say camshafts wear but that isn't my experience. I've pulled quite a few engines apart and not found worn camshafts in any of them. Don't forget if you change the camshaft you'll need to change the followers too so that will push your costs up quite a bit too.

My advice is a new set of rings, new big end and main bearings, new oil pump, new cam chain and bolt it back together.
What viscosity oil have you been using and how many of those miles did you do? RPI Engineering which has rebuilt over 3000 engines insists on 20W50.

Sent from my MAR-LX1M using Tapatalk
 

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Discussion Starter · #7 ·
What viscosity oil have you been using and how many of those miles did you do? RPI Engineering which has rebuilt over 3000 engines insists on 20W50.

Sent from my MAR-LX1M using Tapatalk
Hi,
I bought the Rangey very cheaply at 330,000 km. It now has now travelled about 375,000 km. My wife and I have done considerable cosmetic work on it and it is has largely given trouble free service. It is now much loved.
Obviously I have no idea of it’s past but it’s general condition suggests it was neglected. The engine internals were very dirty, possibly indicating many short runs and perhaps lack of oil changes. Fortunately no real damage seems to have occurred (bore, cam and crank). I am a believer in very regular oil changes with high quality oil. I always use multi grade synthetic 50 weight oil with zinc. My vehicles never get short runs due to my location. It’s primary role is to tow my boat. I doubt it will do a lot of miles in the future. I believe if I carry out this rebuild sensibly it should last me indefinitely
Judging by the low oil pressure and the state of the bearings (all right through to the copper) I have caught it just in time.
thank you for your interest
al
 

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I run 10W-60 Castrol in mine at the recommendation of the engine builder, so 20W-50 isn't a bad idea. It's the first thing I've heard RPi say that I agree with too.....
 

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I am not experienced with the petrol p38 as I have got the diesel, but I have rebuilt a number of other engines over the years.
You need to use a micrometer on the piston to see how much wear there is and if it is within spec.
If the pistons are badly worn you would hear "piston slap" particularly when you rev it when stationary. It sounds awful, similar to a small end gone.
You can check the bores by fitting a ring by itself and measuring the ring gap at the top and then at the bottom of the bore.
If the bores aren't worn and don't have a ridge at the top, I wouldn't get a rebore. Just fit new rings in the old pistons. You need to hone the bores first with a honing attachment on a twist drill.
New shells and other bits as mentioned.
 

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In my experience the only good way to answer your question is to take engine out of the car and take some measurements. I would measure pistons. The skirts are likely fine, and even if they are worn it's not that big of a deal. The piston skirts can be knurled if necessary. What is more critical is the wear of the ring grooves. Install a new piston ring pack and measure the gaps between the rings and the grooves for them in the piston using a feeler gage. If it's out of spec you need new pistons. If you re-ring and reuse the worn out pistons, but you will be back to square one in 20K miles or less. Blue smoke and rings stuck, that is. Be very wary of anyone suggesting that engine can be honed without being bored, it almost never works. The proper repair of a high mileage engine means bore oversize, hone, new pistons, check and recondition con rods if necessary (they are likely stretched/out of round on a well worn engine).

If the block is good, a Rover v8 engine rebuild isn't difficult. The most important skill is knowing what and how to measure. Aside from liner issues, everything else is relatively straightforward on these simple engines.
 

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Also check all the core plugs while it's apart. You cannot see them when it's all assembled, and if leaking will cause overheat in future.
 

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As above, the pistons only need to be replaced if they are severely worn and in that case you'd want to rebore or at least hone the block as well. It doesn't sound like that is necessary in your case, new rings and bearings should get you a long way.
If you're this far in, I would replace the camshaft. The high torque ones are not that expensive, especially if you get a complete kit including timing chain, gears, followers and all seals instead of buying everything separately. I have seen my share of wear on both cams and followers and think the high torque is a good upgrade. I'm using a Kent myself and very pleased with the performance towing the car trailer.

Filip
 

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Discussion Starter · #14 ·
A further update on my 4.6 rebuild!
Hi all,
As a mate of mine claims, I show all the symptoms of ‘Choice anxiety’. I don’t know if this is a real condition or something he has just made up. It generally refers to what car I will choose from my rather large stable to drive up to Sydney to visit him but in this case I think it also refers to how much work to carry out on my ageing 4.6 HSE.
In a previous post I expressed my concern of this rebuilding ‘growing like Tops’. Well perhaps that is already happened.
I‘m quite sure that doing nothing more than honing, re-ringing, a head refresh, oil pump and timing chain and new bearings would have of achieved 90% of what I was attempting to achieve. But now I‘ve removed the engine from car and it is down at my preferred engine rebuilders to be measured up. I suspect it will be rebored with +020” HC pistons, a high torque camshaft and tappets. Not sure if the crank will be ground and whether or not I should fit better head studs.
Anyway, it will be a few weeks until the workshop gets around to commencing the work but I will keep the forum up to date on the progress.
Was it just me but I had great difficulty in removing the cam shaft with the engine in situ. The radiators and condenser were very problematic to move out of the way. Perhaps I was going about it all wrong. As I ended up removing the engine I needn’t of bothered. I also had difficulty with the bell housing bolts being quite tight. Having to use a smallish ring spanner rather than a socket made things hard.

A big thank you to all those who have offered their thoughts to me on this thread
al
 

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whether or not I should fit better head studs.
Any studs are better than the horrible stretch bolts. Stretch bolts may have been fine when the engine was new and LR could specify the exact quality they wanted, these days who knows how close they are to that original spec? Too soft so the stretch easier can mean insufficient tension so the head gaskets won't last, too hard and you risk stripping the threads out of the block when doing them up.
 
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