The V8 Owners Forum -

Has anyone got the all important numbers for a 3.5??

Crank (Big ends & mains), Heads, manifolds, etc....

Cheers
Jono

Mains 55 ft.lb
Rear 70
Big ends 35

Heads 1-10 70
11-14 90

Inlet manifold 30

Exhaust 16

Dave,

Are you sure about that 11-14 figure for head torque? I wouldn't like to go to 90 on any of the stock bolts. Using ARP studs we pulled a thread at 65 just the other week, new block to us so had no idea how good the threads were until we tightened it up, all threads were clean and had been chased. The outer row was deleted by Rover because it promoted the gasket failing into the valley, most people either leave these out or torque low to avoid the problem. I am sure the original manual we have states the same torque all round if you want factory figures.

Alan

My book gives 11-14 as 40-50 lbf ft.

I also have pulled threads with ARP studs.
I now extend the threads on the studs by 1 diameter before fitting. They are hard so you need a good die.
Cheers Denis

DEVONMAN wrote:My book gives 11-14 as 40-50 lbf ft.

I also have pulled threads with ARP studs.
I now extend the threads on the studs by 1 diameter before fitting. They are hard so you need a good die.
Cheers Denis

I've done my Arp's up to 75 lbs ft but all this talk of pulling threads worries me, please stop mentioning it!!

Your idea of extending the thread is a good one!

bigaldart wrote:Dave,

Are you sure about that 11-14 figure for head torque? I wouldn't like to go to 90 on any of the stock bolts. Using ARP studs we pulled a thread at 65 just the other week, new block to us so had no idea how good the threads were until we tightened it up, all threads were clean and had been chased. The outer row was deleted by Rover because it promoted the gasket failing into the valley, most people either leave these out or torque low to avoid the problem. I am sure the original manual we have states the same torque all round if you want factory figures.

Alan

Did a cut and paste from a list - and that was wrong. It should be 70 ft.lb

Very sorry and thanks for pointing it out before any damage was done.

Can't blame anyone for the list being wrong - it was mine. Originally scanned and OCR'd from the BL manual for the SD1. I removed the Nm and kgf.m tables as I stick to lb.ft - if I'd left them in the mistake would have been more obvious.

Just to clarify

1-10 70 lb.ft
11-14 50 lb.ft

In the BL SD1 manual.

Must keep up the meds.

DaveEFI wrote:Just to clarify

1-10 70 lb.ft
11-14 50 lb.ft

In the BL SD1 manual.

Must keep up the meds.

Dave, I would disagree with those figures as well , I'm afraid !!

There was a memo was sent out fromLand Rover quite a few years ago to suggest that the stated 11 - 14 figure was too high and possibly causing head gasket failures. It advised that the outer row of bolts (11-14) only be torqued to 30-35 lbs/ft. On the later cylinder heads , they actually did away with the outer row of bolts altogether.

So this would be :-

1 -10 .........................70 lbs/ft
11-14..........................30 -35 lbs/ft

Regards
Jim
www.jrv8.co.uk

Ok - I'm only giving the figures from my SD1 BL manual, which is the last edition published.

I've read about the outer row being a problem, of course, but assumed it only applied to larger or tuned engines - not the 3.5? Or does the LR memo apply to all engines regardless of age? And with non stretch bolts?

Seems strange it took them over 20 years to find a design flaw.

sidecar wrote:

DEVONMAN wrote:My book gives 11-14 as 40-50 lbf ft.

I also have pulled threads with ARP studs.
I now extend the threads on the studs by 1 diameter before fitting. They are hard so you need a good die.
Cheers Denis

I've done my Arp's up to 75 lbs ft but all this talk of pulling threads worries me, please stop mentioning it!!

Your idea of extending the thread is a good one!

75 lbs ft is getting up there a bit. The ARP instructions recommends 65 lbs ft when the head is aluminium to allow for the expansion of the ali. But all depends of the thread lub you use so 75 is probably ok if you used engine oil.
Fingers crossed every time I torque a head down, not sure if it's worse than going for an MOT.

Cheers Denis

DaveEFI wrote:Ok - I'm only giving the figures from my SD1 BL manual, which is the last edition published.

I've read about the outer row being a problem, of course, but assumed it only applied to larger or tuned engines - not the 3.5? Or does the LR memo apply to all engines regardless of age? And with non stretch bolts?

Seems strange it took them over 20 years to find a design flaw.

I would guess that it's related to the introduction of the composite gasket which need a symmetrical load at the fire ring. More likely to tilt than a steel shim gasket.

Cheers Denis

DEVONMAN wrote:

sidecar wrote:

DEVONMAN wrote:My book gives 11-14 as 40-50 lbf ft.

I also have pulled threads with ARP studs.
I now extend the threads on the studs by 1 diameter before fitting. They are hard so you need a good die.
Cheers Denis

I've done my Arp's up to 75 lbs ft but all this talk of pulling threads worries me, please stop mentioning it!!

Your idea of extending the thread is a good one!

75 lbs ft is getting up there a bit. The ARP instructions recommends 65 lbs ft when the head is aluminium to allow for the expansion of the ali. But all depends of the thread lub you use so 75 is probably ok if you used engine oil.
Fingers crossed every time I torque a head down, not sure if it's worse than going for an MOT.

Cheers Denis

Hi Denis,

I did do them up to 70 ft lbs on the first build but I blew both head gaskets with around 100-115 NOS shot. I then spoke to V8Dev who reckon that they always go to 75 ft Lbs with Arp studs and comp gaskets. I also sprayed the new gaskets with some VHT copper/silicon spray. So far the gaskets and threads have been OK. (I have reduced the NOS shot to 85 BHP). BTW I did use the Arp lube!!!

I don't use the outer studs, I did not use them on my old 3.5 either. (The new lump is a 4.6)

Cheers,

Pete

Pete!

I know folk say it isnt required BUT..... If using arp studs have you tried running a torque wrench over the head nuts when stone cold after a few heating / cooling cylces. Dont loosen then tighten, just set the torque wrench as required and see if any of the nuts will creep up a bit more.

When I fit my heads with comp gaskets I torque to 45 ft/lbs first. Then wait 20 mins and go to 60 ft/lbs. Then wait 30 mins and finish at full torque. I leave this overnight and re check the following evening.
I re check with the torque wrench after several cycles of the engine from full temp to stone cold. It may be complete rubbish but this process lets me know that everything is nipped down as best as possible.

On nitrous only I've had the gaskets let go when I added a 150 shot on top of the old 300 shot.

And with the blower at 10psi they let go with a 150 shot. And the bummer was that I hadnt bothered to do my usual re torque check that time. She had already done several passes with PB's and I decided on this next event to not bother with checking the head torque??

If you lost head gaskets with a 100 shot you either have a problem with bad mating faces or your timing may have been too advanced ??

mgbv8 wrote:Pete!

I know folk say it isnt required BUT..... If using arp studs have you tried running a torque wrench over the head nuts when stone cold after a few heating / cooling cylces. Dont loosen then tighten, just set the torque wrench as required and see if any of the nuts will creep up a bit more.

When I fit my heads with comp gaskets I torque to 45 ft/lbs first. Then wait 20 mins and go to 60 ft/lbs. Then wait 30 mins and finish at full torque. I leave this overnight and re check the following evening.
I re check with the torque wrench after several cycles of the engine from full temp to stone cold. It may be complete rubbish but this process lets me know that everything is nipped down as best as possible.

On nitrous only I've had the gaskets let go when I added a 150 shot on top of the old 300 shot.

And with the blower at 10psi they let go with a 150 shot. And the bummer was that I hadnt bothered to do my usual re torque check that time. She had already done several passes with PB's and I decided on this next event to not bother with checking the head torque??

If you lost head gaskets with a 100 shot you either have a problem with bad mating faces or your timing may have been too advanced ??

Hi Perry,

Thanks for your advice on this subject, I will go over the head studs again as it is not exactly hard to do!

I was running 32 degrees advance with a 2 degree retard when the NOS is running, 32 being quite a lot for a 4.6. I now run 28 degrees with a 3 degree retard.

You've now got me thinking that I can 'up' the NOS shot....oh no, I'm addicted to the bloody stuff!


Cheers,

Pete

I use 28 degree's as my start point with the 4.6 Pete.

Take off another 2 degree's per 50 shot gives you 23 degree's BTDC as a safe start point for a 115hp shot.