head bolts - help.

[benji]

We're having a lot of troubleundoing the outer most head bolts. All the inside ones we've got off, but the outermost ones just don't feel right.

We've got an 70cm breaker bar and it's not doing the job.

Any advise?

[Pierre]

How so, Benji? Can't you get enough torque on them to undo? Does it feel like you're going to pull the thread out of the block?

First up, try a longer breaker bar or get a bigger torque on the 30" bar. Unless someone's used a thread locker on head bolts (and you'll be able to check by the residue on the inner bolts), the TTY bolts remaining have been overdone big time.

Good luck with the outage!

Pete

[slug_burner]

I normally I try a few things on bolts that have seized, mechanical shock and heat cycles normally do it. An air ratchet does a good job of applying lots of little shocks and if big enough will either come or snap the bolt. Getting heat into a head bolt might be a bigger challenge. My mechanic tells me he can burn the head of a bolt with the oxy and not damage the material under it.

[PLR]

G`day ,

as long as your using a single hex socket and an impact type is most suitable i`d suggest , then a length of pipe on the breaker bar will undo them , if the threads pull , helicoils will solve .

If you`re not happy doing that , you can if you have good bits , drill the heads off and then unscrew by hand the leftover shaft , i`ve found .

Use the bolts removed as a guide for diameter .

[Hoges]

I had a similar problem. Blknight came to the rescue with a decent length breaker bar and 6pt impact socket ... he then whispered some inaudible incantation :eek::angel: and the bolt slowly emerged....

I'd be extremely cautious about putting an oxy torch anywhere near an aluminium head! I'd use slugburner's suggestion of using an air rachet to shock the TTY bolt and break any crystalline deposits using a low torque setting (around 40 ft lbs max) so as not to snap the bolt.

Aluminium has a coefficient of linear expansion about 1.5 times that of steel. Heating the head is going to cause it to expand faster than the bolt. While the bolt hole may expand, the head will also expand upwards faster than the bolt will lengthen. So the bolt is going to be 'stretched' and its clamping force increased..

[benji]

Thanks heaps guys, much appreciated.

Some idgit has lock tighted them - that seems to be the prolem.

By shocking them we've managed to get all of them out of the left bank bar 1; it seems to be that the bolts are a poor interface 5/8, and we've rounded two of them so far.

Might leave it for tommorow and go and get a 6 sided 5/8.

[sheerluck]

The breaker bar and 6 pt socket worked on all but one of my head bolts on my V8. I ended up grinding the head off the bolt with a mini die grinder and lots of patience. Took me hours to do, but as soon as the head was off, the bolt shaft undid easily with my fingers.

[Blknight.aus]

if you havent removed the bolts in the reverse of the magic number you my find that the head hass "tilted" and is putting extra pressure on the remaining bolts.

Try winding in the bolts again, tightening them up (in sequence as best you can) then undoing the outer bolts 1/4 a turn.

when removing head bolts (or pattern/sequence tighten bolts) I generally remove them with the reverse procedure to tightening them.

before you go leaning on the long bar make sure you have the best fitting socket you have fitted to the head of the bolt, this may mean using an imperial on a metric and vice versa depending on the quality of your sockets and any damage on the bolts.

[Hoges]

a 5/8 or 16mm 6-sided shallow impact socket should do it. I've also seen advice to hold a brass drift on the bolt head and give it a sharp whack with an "engineer's" hammer to shock the threads vertically.

FWIW:Be careful about the order of removal!! Start from the outside and work inwards to remove. Don't be tempted to forgo the correct order because you don't know what stresses are on the head as regards further warping..

Good luck tomorrow!

[benji]

Managed to get the head off. Banged a 15mm on the rounded bolt.

All looks pretty good actually; except a 4 inch thread of silicon that I pulled out from the front oil gallery out of the block... some further investigation me thinks.

[Keithy P38]

That has to be good for oil flow!

[sheerluck]

Oh dear. Sounds like someone got a little over enthusiastic in chasing oil leaks. Probably worth dropping the sump to see if the oil pump screen has a similar issue.

[benji]

I think a full strip down of everything is needed. Also found a thermostat in the inlet manifold - id love to know who the previous owners mechanic was for I'd give him a sure kick up the clanger!
As I said it all looks good, can see the hone marks in the bores and there's almost no play in the pistons. Everything except for a few spots on the cam are a nice colour too.

Has anyone delt with camtech cams in sydney? I see the offer a 4.6 torque cam.

[Keithy P38]

I'd be interested to hear how it changes the bottom end of a 4.6. They are quite a torquey motor already! More torque than a new Toyota Prado V6 with all the VVTi technology and almost as much as the new 200 series petrol 4.6 with all the bells n whistles - albeit at lower revs too.

If you could get more torque out of it at lower revs than what it already does then I am listening!

[Hoges]

FWIW I ended up purchasing a standard OEM spec cam from Karcraft for a reasonable price... and it works! with new cam, solid steel rockers, new lifters and timing chain etc... all bog standard parts... I am quite pleased with the result.
I refilled the donk with Repco "running in" oil which has a high phosphorus content to bed the cam in properly. Used it for about 500km then switched to Castrol Magnatec 10-40 (on special at Supercheap). It's a very quiet engine now!
Benji, if you get the heads planed, make sure you measure the lifter preload correctly and if necessary purchase some shims to put under the rocker posts...
cheers

[Keithy P38]

Benji, if you get the heads planed, make sure you measure the lifter preload correctly and if necessary purchase some shims to put under the rocker posts...
cheers

Good point Hoges. I found out the hard way when I built up a hot little 179 red motor back in the day! Bye bye studs!

Don't forget to bed the cam in too, varied revs from around 1500 to 2200 for 10 or 15 mins and plenty of heat. Don't boil it, just make sure it's warm and has oil pressure before you bring the revs up.

[benji]

Okay so I've got both my heads off now (bent my 60cm Sidchrome breaker bar).

No real suprises except that piece of silicon. Also found a second thermostate in the inlet manifold (with no housing gasket; they've used roofing silicon instead).

So far i've figured out that they've used Holden lifters (the bleed lifters are 1.6mm shorter than the unbleed Delphi lifters), and the silicon on the leftbank has slowed down the flow enough to starve the rear 2 or 3 lifters, and also the camshaft as i've got slight heat marks on the cam with those lifters.

I few things i'm not sure of though - there's 7.52mm of play in the centre of the camshaft chain - seems excesive to me; but...

The play is so much, and the bottom cog of the chain has floated against the oil pump and caused scoring on the sides of the pump.

The other photos are because I don't really know if this mess is normal.

[TheTree]

Hi

Those heads and pistons are covered in carbon which needs to be removed, you should pretty much have shiny metal on the top of the pistons and the combustion chambers in the heads

Careful use of a copper wire brush and cleaner usually does the trick, be careful not to scratch the heads or pistons. I am sure you will get plenty of tips here :D

You should also relap or replace the valves and seats if needed, IMHO that part of the job is best done by a professional

Check the liners for scoring as well, it's years since i have pulled a motor apart, and i am sure there are other things which will need checking.

Steve

[TheTree]

One other thing, you may have just taken them out for the pics, but while you have the heads off, put clean rags in the pistons to stop any crap getting in there :cool:

[wanglemoose]

500HP SHORT MOTOR - Engines - Triumph Rover Spares South Australia (http://www.triumphroverspares.com.au/page.asp?parentid=5&parent2id=16&parent3id=19&productid=157)


just a thought :whistling: while you have an empty engine bay........

[mtb_gary]

500HP SHORT MOTOR - Engines - Triumph Rover Spares South Australia (http://www.triumphroverspares.com.au/page.asp?parentid=5&parent2id=16&parent3id=19&productid=157)


just a thought :whistling: while you have an empty engine bay........

It's almost worth emptying the engine bay.........Although the cost of a divorce would add up pretty quick ;)

Gary

[TheTree]

I was going to suggest that given all the :censored: this motor has obviously been through, it may be easier and cheaper in the long run to drop a short motor in.

But i also thought that they may wish to enjoy the fun and experience of reconditioning the existing motor.:angel:

I recently saw a 4.6 short motor for around 4K, so not a bad option

Still need to get the heads done, crack tested, valve seats, valve guides, valves, leveled/planed, port and polish, compression chamber balancing .. depends how far you want to go :eek:

Regards
Stvee

[Hoges]

You've really hit the spot Steve! once you start thinking "may as well do xyz while it's in bits" the $$$$ can skyrocket. That's why I went "vanilla" stock standard when I did mine... as it was there wasn't much change out of $1,500.

Well worth getting the heads professionally cleaned up and concentrate on the deck and pistons for the DIY cleanup job. Lanotec "orange" cleaner and the green plastic pot scrubbers +elbow grease get the job done...takes a while but it's worth it ...see http://www.aulro.com/afvb/p38a-range-rover/155035-head-gasket-time-2.html post #18

good advice from this forum also about not reinstalling oil seals on exhaust valve stems to minimise carbon buildup...

[benji]

Thanks heaps guys.

Heads now off to be checked over. Putting in new valve stem seals as they were leaking a bit. I'm pretty sure it's just a clean up for them, and maybe a lap of the seats. No valve seat recession, and all the valves were sealing properly. With the heads upside down on the bench, I filled the combustion chambers with petrol, and there were no leaks out of the ports.

Am trying to keep the whole job under a $1000; though 500hp would be nice.....

I've been talking to one of the guys at Camtech (knows his stuff too); will be ordering it today. New billet ground cam $330 - so I thinks it's reasonable value too.

[Keithy P38]

Is that the torquey cam you spoke of earlier?

I'd love to see a Dyno graph of a factory 4.6 next to a factory one with that cam...

Torque is king.

[Hoges]

FWIW.. I notice that the Camtech Rover v8 cam offerings for all but the #509 are designed for either manual transmission or high stall automatics... perhaps need to get more info on the ZF 4HP22/24 characteristics to ensure you get the correct match. Frankly, given you are wanting to keep the $$$ down, I'd recommend a stock standard cam from Karcraft and get the new lifters and solid steel rockers from Turner engineering UK and a set of ARP head studs instead of the TTY bolts. A Payen metal valley gasket is also worth getting instead of the composite one, and use Loctite 518 "cling wrap' thin to seal it.
good luck with it... this job is not for the faint hearted if it's not your normal day job!;)

[TheTree]

I just found a good article on that valley gasket, and as usual, Hoges is right on the money :cool:

Interesting read

RANGE ROVER WORLD South Africa: Rover V8 - Critical engine failure from composite valley gasket (http://rangeroverworld.blogspot.com.au/2011/12/rover-v8-critical-engine-failure-from.html)

Steve

[benji]

Mmm, ill do a bit of research on that. Thanks. Im pretty sure the lr place in Ballarat would have the steel gasket.

[benji]

Got the cam yesterday. ..yay!
Now I've just got to dial it in. The specs are. 043 of an inch at tdc.

I've found tdc. Made a piston stop out of an old spark plug, tapped with a 1/8npt tap and die some tube in the end of the plug.
I used the teeth on the flywheel instead of a dial guage though, but I feel its accurate.

Ive got the micrometer setup ontop of the pushrod of #1intake, and cam easily dial in the 1.2246mm on a trial run with the old cam.

What happens if the teeth on the cogs dont match up with this measurement; I guess id just go to the closest possible?

Is there anything else before I put the cam in tomorrow. ..
Just a bit nervous.

[Hoges]

Putting the cam in is no big deal except make sure you slather the bearings with assembly lube. Need to be very careful not ot scratch the bearing surfaces. IIRC the cam chain wheel only fits one way once the woodruff key is in place. A little dob of paint on the markers will enable you to tell at a glance when the the top/bottom chain wheels with chain attached are in corect position. Get the cam in place and lay the chainwheels on a flat surfacewith their painted "dots" inline. Then put the chain around them and make sure they are well seated and the dots are still in a vertical line. Then pick the whole lot up and offer the assembly to the crank and cam at the same time...there's minimal play if any in the system. You need to keep the assembly as close to vertical as possible. Take your time. Once you have it in place it should just slide into position. Secure it and turn the motor through 2 revolutions and ensure the dots on chainwheel and sprocket align and the dial gauge shows TDC. Don't forget to replace the camshaft position sensor!!!

Also you'll find that the miniscule endfloat on the cam specified by LR is way out... instead of a fraction of a mm, mine was several mm ...the cam is held in position (front/rear motion) by the chain! I used Repco 10-40W "running in" oil (high phosphorus content) for a few hundred km to settle the new cam/lifters/rockers then changed back to Magnatec. As you probably have learned, the first few seconds of starting the engine are crucial to bedding cam etc. Follow the instructions to the letter. Keep the reports coming!

[clubagreenie]

And please use ARP studs on the heads on reassembly. They are 7/16, 200,000psi set, available on order pretty much anywhere. Midel Fabre in Sydney have about the best prices I've found.

The ARP instructions will tell you use either their moly assy lube or oil, never another brand moly lube. I've always used a generic assy lube and never had an issue but seen a few with oil. 80lbs with moly in 3 steps, go finger tight in sequence then 20, 40, 60 & 80. Or it's 85lbs with oil.

[benji]

Thanks again Hoges, very helpfull.

Where you say to cover the cam bearings with assembly lube, do you mean oil, or breaking in lube that goes on the lobes? I'm using the old bearings shells (obviously), so would they need to be 'cut' in to the new bearing journals on the cam?

Clubagreenie, I've gone against the advise of a few here, and on other forums too and used stretch bolts. There's two reasons for this -

I've heard the nuts should be done up to 70, 72, 75, 77, 80, 85 and even 90NM - I think ARP have revised their torque settings since they've now got a specific 4.6 part number (previously as I understand there was just one part that was designed on a 3.5), but that's a lot of variability on an engine that will be taking us to some pretty remote places.

And secondly, NM isn't a measure of the compression on the head, it's a measure of the friction in the thread and under the head of the nut; and that friction varies a lot - I did a quick test with and without oil to 30 foot pound and ended with a 17 degree difference! I think Rover went to stretch bolts to get a more uniform tension on the head, and when doing the bolts up, all the bolts started stretching (you could feel it) within a degree or two of 40 degrees on the second 90.

I do think the bolts should be a bit longer though, more thread has got to be a better thing, and if I had a 4.0 litre I would definately use the studs.

Swings and roundabouts I suppose.

[Hoges]

I thought about using oil but because it was going to have to sit for a month, I plastered them with assembly lube.

Have you remembered to pack the oil pump with petroleum jelly to prime it?

I forgot to do this...however (there's always a 'however'). I firstly prefilled the new oil filter then fitted it. I had discovered that the M12 x 1.5mm threaded cap opening sitting just above the oil pressure relief valve on the front cover can take a threaded pipe to which I connected a 1/2" polythene hose and so pumped 2 litres of oil through it using one of those plastic centrifugal pumps fitted to a cordless drill ...

very soon I saw oil dribbling from the rocker shafts etc .... When I was ready to complete the 'closure' I poured another litre or two from a jug all over the rocker gear then fitted the rocker covers. When I was almost finished I poured the rest into the normal filler hole. When I started the engine, the oil pressure rise was effectively "instant" although the lifters took a a few seconds to take up and stop rattling...

BTW I used the ARP studs... 3 levels to 65 ft lbs. ARP 'guarantee' their 'lube' material properly applied provides even torquing and that there's no need to retension the heads with the Elring head gasket. I used a Payen metal valley gasket.

[Keithy P38]

To add to that, prior to fitting the lifters it's advised to leave them in a bucket overnight with engine oil covering them. In the morning use a spare pushrod to "pump" each lifter a dozen times or more while still in the oil to pump out any air and effectively prime them.

This will save them dry-starting and becoming prematurely noisy.

Cheers
Keithy

[clubagreenie]

Benji,

I've tested tty bolts from both Toyota (30+ sets) and Land Rover (20 sets). Keeping the reply as brief as possible the variation in final tension, tension after static and running time, amount and location of stretch on the bolt all were outside what I'd conider to be reaonable variation. Without figures in front of me, and specifically looking at the Land Rover product, approx 20lbs variation in tension after static rest. Up to 30lbs variation after a running in period and even one bolt less than finger tight. Stretch should occur in the plain section of the bolt and not the thread and certainly never in the contact section damaging the formed threads in the block. As an aide I always helicoil all thread in alloy blocks and those that are "wet" in iron blocks.

The Toyota product had less variation and no deformation in critical thread areas but still was not acceptable.