Rocker shaft removal???

[stephenlloyd]

Well well,
After my last post requesting assistance with my BMC 1.5 not starting, I must say things haven't exactly improved, but at least the issue may have been found.
My head gasket is gone. Oil in the coolant!
Anyway, have disconnected injection pipes, cooling system, etc etc. Have the rocker cover off, but now...
Cannot get the Rocker shaft out, in order to remove the head nuts!
Workshop manual simply says to remove rocker shaft! How is this done?
I have tried taking the split pin out of the end, and loosening the nuts (not the head nuts, the smaller nuts on the rockers) but cannot budge it. I need the shaft out of the way in order to get the head nuts that are under it loose.
Any tips?
Must be possible, or does everyone just sacrifice an 11/16 spanner and have it bent/welded to fit under the shaft?
Any tips appreciated.
Thanks a lot!

 

[TQA]

If this is the engine I think it is the rocker shaft is mounted to the head by some studs through 4? standoffs.

Remove nuts and lift the shaft off vertically. It can be a bit sticky to get moving Use a persuader.

 

[stephenlloyd]

Thanks for that, the only problem is that some of the nuts holding the shaft are head nuts, and I have to release them in slightly the wrong order to get the shaft off first....

 

[Cliveshep]

Head studs hold down the rocker shaft, but as you are removing the head anyway just take them off and lift off entire shaft. Don't disassemble the rocker shaft.

There was a BMC Service Tool which fitted a torque wrench to do up the head nuts under the rocker shaft assembly, this is no longer available. On re-assembly all you can do is torque down the nuts under the rocker shaft and other head nuts before fitting the shaft and then torquing down the other nuts holding it. For the second torque down after the engine has warmed up those particular nuts are inaccessible without the tool and you have to just check them as best as you can although on a BMC they are unlikely to move again once initially torqued down.

Is yours a Thorneycroft conversion? If so Thorneycroft have technicians giving a free advice service if you call them. You'll find the head is a bit of a lump to get off, have some wooden wedges available as you start to lift it as it slides all the way up the head studs and anything less than 150mm over the top has to be removed to allow it to come clear. My advice is that unless you have (had) valve trouble don't strip the valves out, you'll need a valve lifter and all sorts of seals etc when you refit the collets and it makes it a major job. Just getting the head off is fairly easy as it comes off c/w heat exchanger still attached which gives you something to grab hold of. You'll still probably want a chisel or something to free the bugger off once all the nuts are off though, they stick like crazy. Re-assemble with a thin smear of Hylomar on both faces.

 

[colvic]

Hi
You've taken on quite a job especially as it seems you are new to this.

The people at Thornycroft engines are VERY helpful and will offer all sorts of advice and tips.

Their web page is:http://www.thornycroftengines.co.uk/

 

[Bilgediver]

My head gasket is gone. Oil in the coolant!
*******************************************
This can be expected after an excessive dose of easystart....Throw it away.

This may not be your original problem!!!! Possibly worn rings and pitted valves.

In future if wanting to help start maybe you will find WD 40 less aggressive than easy start.

 

[stephenlloyd]

Thanks very much cliveshep!
Will have another go at it this evening, have left header tank on, with the thought that it may help when lifting /forums/images/graemlins/smile.gif
Will be back on if I have any more hassles

Thanks again to all!