Scottish Elises

Am working on changing the cylinder head gaskets on my V8 Discovery. I bought it on flea bay with the head blown. I’ve now finished one gasket and was trying to get the second head off last night. Unfortunately it seems as thought the prat I bought it from has had a go at fixing it himself, some of the ten bolts on the left cylinder bank were finger tight and he has damaged the head on one. Probably using a metric socket on it. Anyway my Britool 5/8 AF socket, which is fairly elderly is not bighting although the damage does not look too bad, I have not forced the issue (yet).

The socket I am using is a multi point and I was thinking that I might be able to get it off with either a 6 point socket or a flank drive socket. My metric set which is Snap-On has both 6 point sockets and flank drive sockets and my impression is that notwithstanding the claims made re flank drive the 6 point gives better results.

Any engineering types / experienced mechanics know anything scientific about sockets. Realise this is a bit of a sad question but I suspect that I will only get one shot at this and if I mangle the bolt further I will have a very nasty cutting / drilling job ahead of me.

Thoughts gents

The flank drive will take over when the point drive chews the corners off...! I would go with the flank drive TBH. More contact and less likely to mangle the bolt head further.

Are you doing them up or undoing them? If doing them up bin the knackered one (All of them preferably!) and replace, not worth it in the long run.

Thanks Rich,

Am taking it out unfortunatly, no way that it is going back in.

Titanium S1 111S (gla) wrote: Any engineering types / experienced mechanics know anything scientific about sockets. Realise this is a bit of a sad question but I suspect that I will only get one shot at this and if I mangle the bolt further I will have a very nasty cutting / drilling job ahead of me.

Thoughts gents

In theory flank drive is going to deliver more usable torque because the force is spread over a larger surface area of the head. OTOH, the points of the head are at the greatest radius from the center and so deliver more torque for the same applied pressure.

In practice your 12 sided socket has probably rounded the points of the head, so I would now be looking for something that was deliberately flank drive on the basis that the flanks are probably still OK.

I assume you're going to replace the bolt - one fallback option might be to "manipulate" a 15mm 6-sided impact socket onto it - depends on how much metal is missing already - you would need 0.4mm off each face I think, but at around 0.2mm you'll be able to persuade the socket to fit.

Cheers,
Robin

I have often wondered why 12 point sockets still exist after the invention of the ratchet handle.

A six sided socket is far superior and is of course a flank drive that retains corner drive.


I have a set of these tho' for emergency use

http://search.ebay.co.uk/320043353681


that you are welcome to borrow/use

A little bit confused here, first of all to be clear I am going to have to get a large amount of torque onto the bolt, the others which were properly torqued up needed a 24 inch breaker bar and a fair amount of effort. Like most properly designed bolts they were very difficult to turn the first 20 degrees or so and were then little more than finger tight. The one which is chewed is not too bad, I put my socket onto it and applied moderate force which caused the socket to slip, when it slipped I had a look and could see that the corners were slightly rounder, I did not proceed to mangle the bolt (been there done that).

My own experience would suggest that the 6 sided socket is the way to go, which seems to be what Lawrence is saying.

first question 1 is :- are these http://buy1.snapon.com/catalog/item.asp ... oup_ID=358
six sided sockets better than these 12 point sockets http://buy1.snapon.com/catalog/item.asp ... oup_ID=358

If those fail I think I am onto the 6 sided impact socket that is just a bit too wee.

If that fails then bolt grips - Lawrence, do you think I will be able to get enough force through them, I’ve never used them.

Failing that I have several hours of painful drilling / cutting ahead of me.

Further thoughts?

The Irwin sockets are hardened single hex as is an impact socket, additionally it has a reverse cutting screw shape to grab the bolt head.

Robin's comment on torque was only in regards the hex head as the hex corners can transfer a little more torque to the bolt than the flats which are on a smaller pitch diameter.

I agree with Lawrence, 6-sided is the way to go.

Be sure and get a tight fitting socket - even a little bit of slop is going to result in the socket riding over the rounded off corner now.

Good luck!

Robin

6 sided is the way to go 12oints only grip the points and can easily chew them off. Flank drive grips the flats but the can be less successful depending how badly you have chewed the poibnts withthe 12 point.

6 sided should fit like a glove and leave the least room for movement.

I would agree with using the single hex socket but also get hold of
some grinding paste. Works a treat, put some on the bolt head
and inside the socket, it bites a hell of a lot better. Its surprising
what you can get out with it. I use it on aircraft all the time
especially when nice people put rounded screws but in, saves
the hassle of drilling them out.

Kev wrote:I would agree with using the single hex socket but also get hold of
some grinding paste. Works a treat, put some on the bolt head
and inside the socket, it bites a hell of a lot better. Its surprising
what you can get out with it. I use it on aircraft all the time
especially when nice people put rounded screws but in, saves
the hassle of drilling them out.

Kev do you work on Embraers at ABZ ?

Sure do. Nice little number.

Kev wrote:Sure do. Nice little number.

Are Colin Feguson and Stevie Macateer still coining it in up there ? If so be sure to give them plenty of abuse from Alan in Glasgow .

A while back I worked for Caledonian with a few of the guys , my worst job to date.

Kev wrote:

I would agree with using the single hex socket but also get hold of
some grinding paste. Works a treat, put some on the bolt head
and inside the socket, it bites a hell of a lot better. Its surprising
what you can get out with it. I use it on aircraft all the time
especially when nice people put rounded screws but in, saves
the hassle of drilling them out.

Thanks for the top tip, a dod of grinding paste in the socket it is.

Colin left about a month or so ago, gone out to Dublin then Paris, back
on the 146's, Cityjet rings a bell. Stevie's still up here, great guy.
Dont get to see him much as he's on the opposite shift, but next time
I do, I'll be sure and pass on the abuse.

tenkfeet wrote:A while back I worked for Caledonian with a
few of the guys , my worst job to date.

Your not the only person I've heard that from, come to think of it,
don't think I've heard anything good about the company.