Timing Chain / Cam Cog socket size

[factotum]

Can anyone help? I'm rebuilding the engine from my 68 Traveller and need to remove the Timing Chain / Camshaft cog drive and need to source a 1/2" drive socket that fits. It's larger than anything I have in my toolkit!

Does anyone know what size this is? I'm guessing it will be AF? possibly 1 5/16"?

Thanks
Graham

[philthehill]

The socket required is 1-5/16" A/F
.
Here is a link to a supplier:-

http://www.ebay.co.uk/itm/DRAPER-24525- ... SwstxVbE94

Because the camshaft nut is quite thin (5mm) I have ground the bottom of the socket away to remove the inside chamfer.
Removing the inside chamfer allows the socket to grip the nut much better.
Phil

[bmcecosse]

Indeed -as Phil says - a socket is not ideal here - I have a nice big 'open ender' for this job. Works well - and no 'offset' forces as you struggle to release the nut.

[philthehill]

If you want an open ended spanner how about this one:

http://www.ebay.co.uk/itm/NEW-But-Vinta ... bxqOu9HpZg

[bmcecosse]

These are good - I have a set - but Metric

[philthehill]

So good I decided to buy one

The good thing about single ended spanners is that they are usually the right length the give a reasonably accurate torque setting without having to use a torque wrench but of course if you have a torque wrench use it.
The camshaft nut should be set to 65lb ft.
Phil

[andypocock]

Or for a real period feel:

http://www.ebay.co.uk/itm/310382850223

[bmcecosse]

Its a very thin nut Phil - are you sure about that torque figure? Looks a lot to me. As you say - a good heave on the open ender has always been good enough for me. After all - the torque is being restrained only by the chain..

[philthehill]

bmc
The nut is thin but a very fine thread (similar the rear hub nut which has a high torque setting relative to the depth of thread).
The several BMC / BL manuals I do posses do not appear to give an official torque setting (I am happy to be corrected) only saying tighten the cam shaft nut.
The other various manuals relating to the 'A' Series I have give a torque of 60 - 70 lbft for the camshaft nut.
I have used that torque setting successfully for many years and have had no problems.
To alleviate any strain on the timing chain when tightening the camshaft nut - put a large screw driver through one of the holes in the camshaft timing gear and the hole in the front of the block. Holding the screw driver in place will stop the camshaft gear from turning so enabling the camshaft nut to de done up with ease.
Phil

[bmcecosse]

Good idea!

[factotum]

Phil, BMC & Andy - thanks all for great feedback.

I will try Phil's advice with the socket - I use an impact air wrench and I'm hoping this will work with the modified socket - although I'll also order up an open ended spanner as back-up!

Once removed my intention is to remove both Cam & Crank shafts - is this pretty straightforward once the timing gear is out of the way?

Graham

[factotum]

Sorry I should have mentioned - I've already removed top end plus pistons etc so only bits left are the cam and crank shafts.

Graham

[bmcecosse]

Remove the dizzy drive shaft first. Remove the triangular plate (3 screws) - note which way round it is fitted! Then ease the cam out carefully so it doesn't damage the bearings. Remove the oil strainer. Undo the main bearing cap bolts (note which way round the centre cap fits) and lift out the crank. Maybe need to remove the front plate - can't remember if it slips out with the plate fitted.

[philthehill]

Once the timing gears and chain are out of the way the cam retaining plate can be removed. Remove front engine plate - there is part of the front plate gasket between the front engine plate and front main bearing cap that will most likely tear away when the front main cap is removed so best to remove front engine plate. Remove centre and rear main caps and lift out crankshaft. Do not disturb the top half of the oil thrower cap attached to the rear of the block.
Turn engine block so that the front of the engine is facing upwards - remove distributer drive and lift camshaft out of block being careful not to mark the white metal cam bearings. There is less chance of damaging the cam bearings if the cam is lifted vertically out of the block rather than being slid horizontaly through the cam bearings.
Phil

[factotum]

Thanks again gents. I've set a couple of hours aside on Friday to complete this - have taken on-board your advise.

Graham

[philthehill]

I have today received the 1 5/16" UNF open ended spanner (see link in my post above) and I am very pleased to report that it is most suitable.
As the spanner jaws are 12.2mm thick (and the nut 5mm thick) I am tempted to take a couple of mm off one side of the spanner to ensure that any effort is placed centrally in relation to the nut.

[philthehill]

I can confirm that the torque setting for the Minor camshaft nut (Pt No: 6K629) is 60 -70 lb ft.
I found the torque setting in the BL Marina Repair Operation Manual AKD 7555 Issue 3 Section Torque Wrench Settings.
Strangely enough it is not listed in the Marina/Ital 1098cc/1275cc engine section but in the Marina/Ital 1800cc section.
The camshaft nut (Pt No: 6K629) and therefore the threads are the same whether fitted to a 1800cc MGB (4 & 5 bearing), 1500cc diesel, 1275cc Marina/Ital or a 80cc/948cc/1098cc Minor plus all the other 'A' series variants.

Richard - Can this torque setting please be added to the torque setting list at the head of the Technical Section.
The nut size is 1 5/16" AF.

Phil