Not much actual progress to report on the car - but the pile of parts is growing...

Just thinking ahead - and on the question of head bolt torques. Obvs the manual is all about the 20nm /90' /90' procedure. A few posts back Richard said a final figure of 65-70lb/ft via 3 rounds of 40, 55, and 65.

Being of the Nm generation, can I just check that? For 70lb/ft I get a final figure of 95Nm - which just seems low given the palaver I had getting the OEM stretch bolts out.

95Nm is no problem - got good tools that can manage that accurately, it's just that the figure doesn't square with the fight I had getting them off!

Peace of mind gratefully accepted!

When I picked my bottom end up, along with a set of studs, from V8 Developments, I asked what I should torque them to and was told 80-85 Nm. That meant nothing to me until I converted it to lb/ft (being an old bugger) and it seemed a bit on the low side. Hence setting on 65lb/ft (88 Nm) as that was the same as I'd used on similar alloy engines. With the stretch bolts it is like attaching the heads with a big spring, the bolts are always under tension hence the difficulty in getting them out.

Fair enough that seems pretty definitive, if maybe a little counter-intuitive.

What I mean by that is, for example that you read about the crank pulley nut being the 'biggest torque on the engine' at ca. 250nm or something. My rattle gun takes that off in seconds - yet won't really look at the head bolts which will be < 100nm (nominally at least). I'm not expecting an answer to that - it's just a wee puzzle!

Thanks again.

I totally agree with what your saying Don , to get them out is a joke, I also agree with Richard, ( even though he used studs ), I used to pull them up to 70/75lb ,
I’ve done quite a few head jobs, from memory I only got 2 of them to pull up to the second 90 degree.
Only had one strip a thread, on my car ,, following the 20nm, 90/90

I was terrified of stripping the threads when I did the HG’s on my Disco. When I do the P38 I’m not sure yet whether I will use ARP studs or TTY bolts.

^^ Thanks guys. I'm using the studs. I'd never heard of them till mentioned on here but it seems to win both ways - a more predictable torque application across the head ( not subject to the vagaries of different bolts stretching more or less than others) and just plain easier to fit.

Been away, and trying to work around a little injury which affects mobility, so there's not a great deal to report but yesterday I cleaned off the block faces (p800 wet 'n dry) for the head and front cover gaskets, as well as the gasket faces on the inlet manifold. Happy with all of that. Expecting to get the heads back next week. Might go out and clean up / prep the sump today and clean out all the bolts that I'll be re-using. Exciting, eh!

Couple of quick questions though - camshaft timing and running in related.

The new cam has some complicated instructions relating to timing - using dials etc etc. A lot more complicated than what Richard has said above about lining the timing gears up and slotting them on. ( Not doubting it! - just checking my understanding). As far as I can see, once the chain gear is one the cam, there isn't really any further adjustment possible - it's a tight enough fit - maybe half a degree either way.

Do I really just ditch those instructions on the basis that they are for other engines where such adjustments of angle are needed?

Secondly - it says it's really important to run the engine at ca. 2500 revs for the first 20 mins or so. That's really counterintuitive ( and frankly scary ) after such a big rebuild. I haven't looked at all yet into filling/priming the cooling system, or the oil pump, but the idea of just turning the key and revving up straight away worries me a bit. I'd hope not, but there could be all sorts of leaks or issues, or at very least it makes sense to anticipate them. Hard to do when you're sitting in the driver's seat with your foot on the pedal!

I will be using an assembly grease on anything that looks like it might benefit from it - cam, followers, pushrods, rocker pads, timing chain etc.

Any thoughts or experience on this?

Thanks

You haven't got a vernier cam sprocket or anything clever like that so there isn't any adjustment for the cam timing other than moving it a tooth one way or the other. The cam is bolted to the sprocket and can't be fitted any other way than correct so just use the provided timing marks.

I've also been concerned about the cam running in procedure, it doesn't seem right to fire up and engine with lots of new bits in it and immediately start revving the goolies off it. It always used to be the case that you ran a new engine in by keeping the revs down. When mine went back in I ran it at around 1,500 rpm initially by screwing the throttle cable adjuster out a bit to get the revs up. At least that way you can have a good look around for any leaks, keep checking the temperature, etc.

My method for filling the cooling system from dry is to initially fill it through the top hose. When you can't get any more in there, refit the top hose to the radiator and fill the header tank with the bleed pipe at the top of the rad disconnected. If you squeeze the top hose, then put your finger over the bleed pipe on the rad, then release the top hose, you'll draw coolant in from the header tank. Keep doing that until coolant dribbles out of the bleed nipple, then refit the hose and carry on doing the same only this time you can plug the hole just inside the header tank neck with a finger until coolant flows out of that without and bubbles and you can no longer hear the coolant gurgling around inside the engine. Then you know you've got as much air out as you are going to. Start the engine, run it with the header tank cap off and the level will drop a bit and the flow from the bleed will be a continuous stream. Then you've got all the air out.

I'm also suffering from restricted mobility at the moment so know exactly what you mean. I blame lockdown for it. Decided to have a run on on my motorcycle (600cc Yamaha) 4 weeks ago but had only done 60 miles on it in the last year. Due to lack of use found I'd forgotten how to make it go round corners, clipped a kerb at about 45 mph and found myself sliding down the road following the bike. Relatively minor damage to the bike, destroyed crash helmet and leather trousers, a few bruises that cleared in a week or so, but left thumb and wrist whacked by the handlebars and right thigh muscle badly bruised making walking a painful experience don't seem to have got any better yet. I'm getting really, really pissed off with not being able to get on with things I want to do......

The reason you run engine at 2000rmp is to reduce loading on cam lobes 🤗 low revs =drag=friction---- heat 🤗

Thanks both,
Yep, I understand the reason behind the revs. The instructions specifically say it's to achieve good oil pressure and good. lubrication. It's just a worry when there will be so many new gaskets, remade joints and disturbed systems. Not to mention gassing myself in the garage! Reckon I'll choose a good day and get it out into the open asap!

That's a clear enough procedure for the coolant fill. I think I'll print that off and keep it to hand when I get to that stage.

Your accident is a lot more dramatic than my issue, Richard. I just got a stress fracture in my foot through exercise, which has brought on my second ever inflammatory arthritis attack (aka gout). The pain is 'considerable'.... I can't afford to take a month away from life's commitments completely at random, so I reckon I'll be on the pills from now on. I can't even bend my foot to pick something off the floor, far less clamber up and down from underneath the car. Oh for a 4 post ramp and the garage to go with it.

Glad you got through your accident 'relatively' unscathed. Bad enough as it is, sounds like it could have been a lot worse.

my engine run in process is to get everything running properly and on the first drive head to an open road and drive at a consistent speed for 15/ 20 mins also let it drop to a low rev and build it back up in a hi gear , this sets the bearings . do not let it labor or rev hard just drive with care for first 300/500km then start to drive it like it will be driven .
PS if the motor is tight from the rebuild do not rev it as it will seize , it can take 5000km for a tight motor to loosen up. you will know its tight it will refuse to go and to push it will seize it , just let it do its own thing until it loosens.
sorry to hear Richard fell off his bike , hope you stop hobbling soon . we don't bounce like we use to .
my cure for gout is rap in cotton , soak with cider vinegar and a couple of drops of lavender oil (100%). the cider vinegar takes out the swelling and the lavender takes out the sting, works for me.

I've often wondered about the conflict of interests between what 's good for running-in most of the engine versus what's good for running-in the cam.

David Vizard used to recommend using an oil stone to remove the sharp edges from piston rings, reckoned this allowed running in the bottom end at a bit higher rpm which helped with running in some of the high lift cams he fitted.. but I suppose that won't help the engine bearings. Maybe ideally a new bottom end should be fitted with old cam and heads until the bottom end is run in, then the engine pulled and new cam and heads with new valve gear fitted lol.

Sorry to read about your accident Gilbert.

If you had time you could weigh individual Conrods and make sure they are all same weight --- same for pistons ---- you would be surprised at variance on some engines ---- you can get special rebuild oil ---- it's expensive but worthwhile

I remember being told years ago that you should fill an engine with the cheapest, lowest quality oil you could get for the initial running in period, then drain it and fill with decent stuff. The logic being that during running in, the parts surfaces are supposed to wear to each other so you don't want anything that will lubricate too well or the parts won't bed in properly.

just use a non friction modified oil, highly recommended, as the friction modified oil dose not allow the engine to bed in. your right Richard,it is a thing.

Running in oil

With lots of yummy zinc for all those cam lobes and tappets....

I hadn't thought of running in oil, given that it's 'just' the cam, tappets and pushrods that have been changed. Presumably with its high Zinc content there's little chance of it causing any damage to the rest of the engine, that's already well run-in? Just run it sensibly for 500 miles then drop it out?

At the risk of stirring up all the worms in the tin, the link above also 'highly recommends' an engine flush. I'd gathered the impression that these potions were just snake oil? Though I have to say, when I drained and removed the sump there was a lot more 'sludge' than I'd expected. In my ownership my diesel LR Defender has had very regular oil changes. Sump was very clean, as was the underside of the pistons last time I looked. Would the sludge in the RR sump indicate anything? Service book suggests regular changes, but low miles in between.

Finally - though I've been here a bit now, still ready with the numpty questions..... the heads came back from the machine shop with the rocker shafts fitted. I'm assuming I need to remove them again in order to fit the heads? (Can't see any other way I'll get the pushrods in?). Guy also said I'd need to adjust the tappets - but as they're hydraulic, that won't be an issue.. unless I've missed something?

Fingers crossed I'll be at this at the weekend.

Yes, you will need to remove the rocker shafts to refit the heads. It will also give you the opportunity to check the pre-load. Unless they have skimmed a lot of metal off the heads, it's likely they will still be in spec so the hydraulics will self adjust. If the heads have been skimmed, then you may need to adjust the clearances but that is done by putting shims under the rocker pedestals. How to check is here http://www.v8developments.co.uk/technical/valve_train/index.shtml

Thanks Richard - I think it was the very minimum they took off. 3 thousandths... I'm largely metric, so 0.0762mm doesn't sound like much!

That sounds about right for an engine that hasn't had a blown gasket. My heads have been skimmed three times that I know of and the last time they took off 8 thou. When I checked the preload on mine I had to put the shims in but with only 3 thou off them you shouldn't need to. I had to buy a set that came with three different thicknesses and I found the thinnest ones put it just inside the range while the middle ones put it nicely where it needed to be. So if you do need to shim, which sounds pretty unlikely, I've got a set of shims that should do the job nicely you're welcome to if you need them.