Cylinder Head Bolt size

[e635815]

Dead all,
I Need to take my off side cylinder head off.
The first plug didn't go as planned and the thread is now f@@@@@.
There are two rows of head bolts with the integrated washer.
Been trying to use a 14mm socket but they don't want to move at all.
I suspect 14mm isn't the right dimension and it should be an imperial size instead.
Does anybody know for sure what socket size I should be using for these?
Thanks and regards
Philippe

[Steve_D]

If 14mm is close then 9/16" imperial will be what you want.

Steve

[BeastMaster]

Just so you are aware.

The cylinder head bolts are StretchBolts and are quite scary the amount of force to tighten or remove to the correct value.

I needed a breaker bar about 1m long to shift mine, and when they shifted the crack noise made my heart skip

Suggest you get a good fit quality socket and a second pair of hands to make sure the socket does not slip off the bolt.

Remove in the correct order to avoid head distortion and always use new bolts, as used stretchbolts will not work a second time.

Good luck

Andy

[e635815]

Ok, very good inputs. Thanks a lot for your inputs.
But What about the bolt head size, is is the 14mm or the Imperial equivalent?
Also, you are talking about the correct sequence of removal but what is it exactly, this order?
Thanks a lot for the info.
Philippe

[Sardonicus]

Word of warning 14mm will be a better fit than 9/16 and dont use a bi-hex socket you want single hex for better location/purchase on the bolt head 1/2 drive and preferably using a breaker bar keeping things parallel to the bolt (no rocking or tilting) whilst you try to crack them loose

[caduceus]

I'll go out and check later what socket I used when doing mine. From memory it wasn't anything unusual.

[Sardonicus]

caduceus said:

I'll go out and check later what socket I used when doing mine. From memory it wasn't anything unusual.

Its not anything special but if those bolts are reluctant to move I suggest using pukka quality/appropriate tools unless the OP'er likes drilling or grinding off bolt heads and all the associated grief and mess that causes

[BeastMaster]

e635815 said:

Dead all,
I Need to take my off side cylinder head off.
The first plug didn't go as planned and the thread is now f@@@@@.
There are two rows of head bolts with the integrated washer.
Been trying to use a 14mm socket but they don't want to move at all.
I suspect 14mm isn't the right dimension and it should be an imperial size instead.
Does anybody know for sure what socket size I should be using for these?
Thanks and regards
Philippe

Hi Philippe

Have posted re headbolts above but looking again at your post maybe a better understanding of your plug thread problem may help.

How bad has it been crossthreaded, the plugs are a little tricky to get at the correct angle to start the thread, and made more difficult because of poor access.

Has it been forced in several turns or just a couple which have damaged the starter threads making it impossible to get another plug started.

I do not know you or you capability but IMHO would seek some professional help before pulling the heads, as it may be possible to rescue the situation with some specialist know how.

The plugs are difficult and so easy to cross thread, or not tighten up properly - I insert the plugs in some flexible pipe and wind them in with this, with a final nib with a socket but need to be patient and sure it is started before adding any grunt.

Andy

[e635815]

Ok, very good inputs. Thanks a lot for your inputs.
But What about the bolt head size, is is the 14mm or the Imperial equivalent?
Also, you are talking about the correct sequence of removal but what is it exactly, this order?
Thanks a lot for the info.
Philippe

[BeastMaster]

e635815 said:

Ok, very good inputs. Thanks a lot for your inputs.
But What about the bolt head size, is is the 14mm or the Imperial equivalent?
Also, you are talking about the correct sequence of removal but what is it exactly, this order?
Thanks a lot for the info.
Philippe

As stated above its an American engine so will be AF sizes.

Regarding the head bolt sequence you need to get a overhaul manual for the Rover V8 which will tell you all you need to know.

Its a bit more complex than just giving out information as depending on the year and engine number prefix will detail how many head bolt are used. You may find that not all the bolts are used because of warping problems.

If you are going to be rebuilding the top end you will need the manual, so just download it now and you will be sorted.

Andy

[Chimp871]

Sardonicus said:

Word of warning 14mm will be a better fit than 9/16 and dont use a bi-hex socket you want single hex for better location/purchase on the bolt head 1/2 drive and preferably using a breaker bar keeping things parallel to the bolt (no rocking or tilting) whilst you try to crack them loose

+1 so true! So important to single hex socket (6 sides) it grabs much better than the 12 side bi-hex socket. You'll use a lot of force to break the seal and as Sardonicus says keep it square on the head or you'll round it and fly backwards. The bolts near bulkhead are the hardest.

Undo sequence is release pressure from outside in to avoided warping heads. Google is your friend...

[Chimp871]

Try this for sequence

https://www.google.co.uk/url?sa=t&source=web&a...

[e635815]

Shame on us!
Shame in me for having mistaken 14mm and 16mm.
Shame on you for not spotting my mistake and talking about 9/16" when the actual socket size I need is 5/8".
Now I have a beautiful 14mm long Facom socket which I will probably never use 😂

Back to Amazon to procure the right one..... next time I'll check upon reception of the tool instead of wasting another two weeks.

More to come at the next episode.

[e635815]

Shame on us!
Shame in me for having mistaken 14mm and 16mm.
Shame on you for not spotting my mistake and talking about 9/16" when the actual socket size I need is 5/8".
Now I have a beautiful 14mm long Facom socket which I will probably never use 😂

Back to Amazon to procure the right one..... next time I'll check upon reception of the tool instead of wasting another two weeks.

More to come at the next episode.

[Sardonicus]

Wouldnt know I never use yield bolts on the RV8 only ARP I assumed you would quote the correct metric size I was only quoting the correct equivalent, did you get it all done?

[Discopotatoes]

I would have thought if you were attempting to remove the heads you would be competent enough to measure the head of the bolt yourself and have a full set of imperial and metric sockets a breaker bar and a torque wrench. if not how to you expect that jobs going to end up, apart from in tears?

[ClassicChimaera]

Discopotatoes said:

I would have thought if you were attempting to remove the heads you would be competent enough to measure the head of the bolt yourself and have a full set of imperial and metric sockets a breaker bar and a torque wrench. if not how to you expect that jobs going to end up, apart from in tears?

made me laugh,, I'm sure it's an honest mistake and I was wondering when someone would mention you'll need a quality breaker bar too.

[Sardonicus]

Discopotatoes said:

I would have thought if you were attempting to remove the heads you would be competent enough to measure the head of the bolt yourself and have a full set of imperial and metric sockets a breaker bar and a torque wrench. if not how to you expect that jobs going to end up, apart from in tears?

Too true e635815 your in trouble now fella

[peaktorque]

e635815 said:

Shame on us!
Shame in me for having mistaken 14mm and 16mm.
Shame on you for not spotting my mistake and talking about 9/16" when the actual socket size I need is 5/8".
Now I have a beautiful 14mm long Facom socket which I will probably never use ??

Back to Amazon to procure the right one..... next time I'll check upon reception of the tool instead of wasting another two weeks.

More to come at the next episode.

Don't bother, just get a 16mm non-multi point socket from machine mart. I had grief getting my head bolts off, the £2.50 socket from MM was the only thing to touch them.

Edited by peaktorque on Sunday 19th March 19:33

[e635815]

Job's not done yet. I have ordered the correct size socket and awaiting delivery.
Well well well... I have lost all hops to finish the car on time for the driving season
Never mind, at this rate I'll have the complete set of long 6-points socket before the Chim is again on its wheels.