#10 Head Bolt torque

[sunshineking]

Had my heads redone for my 98 Discovery I and i am in the process of remounting them back on the block.

Can anybody describe a good procedure and tools/special sockets for tightening the head bolt #10( short bolt close to the firewall) to the specified torque?

I had all the bolts torqued to 20Nm first then 90 degrees but for the last 90 I can't really apply that much force to this specific bolt and don't want to end up with a rounded head bolt..

[p76rangie]

Remove the rubber engine mounts. This will lower the motor and also tilt it more forward. This will then allow you better access to the bolt.

It is important to get the rear bolts correct as incorrect tensioning of these bolts is the most likely cause of the head gasket going between the rear cylinders and the water gallery.

It is too late now, but you would have been a lot better off with studs instead of bolts as they allow better tensioning of the head.

[sunshineking]

thanks Rangie..
yeah I was thinking about the same thing ..remove the mounts..the only problem is the fact that the oil pan is off and no way to support the engine..I guess I will temporarily mount the pan back and use a jack and block of wood to support it.
Who sells the stud set for this specific vehicle?All i've seen is only head bolt sets...

[pavel]

sunshineking: #10 is a bugger. I broke 2 sockets (Proto & Craftsman) taking #10 out last time. Used a 2x4 between the breaker bar and the fire wall to hold the bar & extension vertical over the bolt head.
To torque and tighten the extra 90 degree turns I got help from my 20 yr old son. Didn't play with the engine angle. We made a slot in a piece of wood that accepted the top of the breaker bar; then he pushed down on the wood as I turned the bar & watched the dial gauge for the correct angle. We were not able to do the last 90 degrees in one continuous turn - ended up doing it in about 30 degree turns which is poor technique.
After 2 years she still seems OK. I really dislike working on aluminum engines!
Best of luck.

[Badger1]

Ireally dislike working on aluminum egines!

I'll second that! Plus the bolts on LR's seem to like to snap, wish the Brits would learn to put real bolts on these things.

[pavel]

Yes the available headbolts seem to be by different manufacturers. We ended up using the expensive LR bolts because they had larger heads with better/sharper hex angled top faces. We returned a different set (cheaper, non LR) due to poor thread quality and head design. You can't trust anything these days - unfortunately.

Badger1: I notice you are from Loo-eee-ville, Ky. We met a young computer lad from your town while he was working at Microsoft in Washington State and he insisted that the correct pronunciation is "Lowal". Being from the Northwest, I obviously didn't argue with him but was he just feeding me 'a line'?

[p76rangie]

Originally Posted by sunshineking

thanks Rangie..
yeah I was thinking about the same thing ..remove the mounts..the only problem is the fact that the oil pan is off and no way to support the engine..I guess I will temporarily mount the pan back and use a jack and block of wood to support it.
Who sells the stud set for this specific vehicle?All i've seen is only head bolt sets...

You only remove the rubber engine mounts, not the metal bracket bolted to the engine. The metal mounts (the things the rubber mounts bolt to) will meet and support the engine.

[Elemental]

Short Socket on a short swivel extension. It really makes it much easier.

[sunshineking]

Hi Guys,
thanks for your help ..finally got both heads back on.Unfortunately that #10 head bolt on driver side-left cyl head got rounded in process so fo the last stage I was able to get it torqued to only about 40degrees instead 90..I will try to remove it tomorrow and pickup one from the local dealership...

Any advise on how much torque do i have to put on this bolt /follow the same procedure -15lbs-90-90? Should I get a whole new set for this cyl head instead one bolt only?


Pavel you were right about the quality of the aftermarket head bolts.. they're
notvery good at least the set I got. You can almost feel the socket rounding the head of the bolt during the last stage..
Not having another person helping you do the last 90 degrees of torque makes it very hard for one person so I followed Rangie's advise and removed the 2 rubber engine mount shock absorbers from both sides of the engine
( took me about 10 min for each side with the help of the engine hoist-jack and a block of wood works as well) .

Night and day difference once the engine is lowered a bit..you have enough space to work around the cyl head when you do the torque..
My 24" breaker bar was not long enough to have enough leverage so I used a piece of pipe and this way i can apply pressure down on the socket with one hand while rotating the bar with the other..

Impact sockets ..a must for this job....preferably a new or not abused socket..

[p76rangie]

Using a different brand of bolt may cause issues as it would heat and expand at a different rate to the others. If the bolt is only rounded on the tips, try getting a socket that is the shape of the top of the bolt (hex) rather than the type of socket that just grips on the outer edges of the bolt.

[sunshineking]

I used a brand new 16mm 6 point impact socket but the material of the bolt seems to be soft and can be rounded very easy.. Do you suggest tryin to file the hex head to a smaller size?

I will probably get another bolt from the same vendor rather than dealer if a
different bolt will cause issues.
Since all the other bolts are already torque to specs do you have any advise on the torque procedure for this bolt?

[p76rangie]

Originally Posted by sunshineking

I used a brand new 16mm 6 point impact socket but the material of the bolt seems to be soft and can be rounded very easy.. Do you suggest tryin to file the hex head to a smaller size?

I will probably get another bolt from the same vendor rather than dealer if a
different bolt will cause issues.
Since all the other bolts are already torque to specs do you have any advise on the torque procedure for this bolt?

If the bolts are so soft, I would be concerned about all of them. But I am not sure whether you can re-use the head gaskets if you replaced all the bolts now.

In regard to replacing the single bolt, all you can do is just put the new one in and torque it down.

[Badger1]

Originally Posted by pavel

Yes the available headbolts seem to be by different manufacturers. We ended up using the expensive LR bolts because they had larger heads with better/sharper hex angled top faces. We returned a different set (cheaper, non LR) due to poor thread quality and head design. You can't trust anything these days - unfortunately.

Badger1: I notice you are from Loo-eee-ville, Ky. We met a young computer lad from your town while he was working at Microsoft in Washington State and he insisted that the correct pronunciation is "Lowal". Being from the Northwest, I obviously didn't argue with him but was he just feeding me 'a line'?

No the locals pronounce it Loo-vull(they say like they have a mouth full of marbles). I am not a local so I rib them by saying it how it should be pronounced Loo-isss-vill, or Loo-ee-vill, all in good fun though.


Sorry for the high-jack!

Back to the head bolt.

[apbtpetey]

Originally Posted by sunshineking

Hi Guys,
thanks for your help ..finally got both heads back on.Unfortunately that #10 head bolt on driver side-left cyl head got rounded in process so fo the last stage I was able to get it torqued to only about 40degrees instead 90..I will try to remove it tomorrow and pickup one from the local dealership...

Any advise on how much torque do i have to put on this bolt /follow the same procedure -15lbs-90-90? Should I get a whole new set for this cyl head instead one bolt only?


Pavel you were right about the quality of the aftermarket head bolts.. they're
notvery good at least the set I got. You can almost feel the socket rounding the head of the bolt during the last stage..
Not having another person helping you do the last 90 degrees of torque makes it very hard for one person so I followed Rangie's advise and removed the 2 rubber engine mount shock absorbers from both sides of the engine
( took me about 10 min for each side with the help of the engine hoist-jack and a block of wood works as well) .

Night and day difference once the engine is lowered a bit..you have enough space to work around the cyl head when you do the torque..
My 24" breaker bar was not long enough to have enough leverage so I used a piece of pipe and this way i can apply pressure down on the socket with one hand while rotating the bar with the other..

Impact sockets ..a must for this job....preferably a new or not abused socket..

I wouldn't mix different bolts, so if you can get a bolt from the same place you got your set from I would do that. I wouldn't drive it, instead get the new bolt and remove the rounded one. If you don't run the engine you should be fine just taking the old one out and putting a new one in its place. Also I second Elementals suggestion of using the short socket and swivel for that bolt. When I did mine head gaskets that bolt was a pain, but using the right tool for the job makes a big difference. I didn't use impact sockets at all, just my normal everyday craftsman sockets worked just fine.

[pavel]

sunshineking: you said you were unable to fully torque down the #10 bolt (last 90 degrees) so you may not have fully compressed the head gasket at that point. If you can get the damaged bolt out, you could risk just replacing it with another identical bolt. Even with the correct 6 point short socket and a lowered motor, it would better to get some help. As I mentioned, a piece of wood (modified 2x4) set up to put pressure downwards on the bar & its socket really helps... All the best - hope you don't have to start again....