As promised , for britbike 220 and hungry joe ( and whoever is interested ..) a photo tutorial to replace seals without removing cylinder head .
First of all : I am inventing nothing new here .
This job is done on cars all the time , using compressed air and a special valve retainer removal tool .
This tool can't be used on a Norton , because of lacking space over the valve .
I don't like compressed air because the hissing sound of air escaping somewhere drives me crazy ..
The makeshift tool in the other thread + rope will work , but I believe making proper tools really pays .
The job will be done much easier , faster and safer .
If you ever where to change the seals on a V8 using the rope trick , you'll EAT your rope out of sheer frustration before you are done ..
So let's make the tools first :
T1 : valve spring compressor
T2 : valve stop
bend a strap of metal , or cut from any U-shaped profile , roughly these dimensions in mm :
don't make it shorter , or you'll have troubble compressing the valve spring deep enough
It must be quite strong for stability , but the thinner , the more space you have for fidling with the collar retainers .
The central bolt is about 5 cm long .
because threaded rod with the correct British thread is impossible to find ( for me ) , I made it out of 2 parts , using M5 rod and an old valve adjuster :
If you don't have spare valve adjusters , or have a problem with drilling and tapping the adjuster ( a lathe comes in very handy )
you can also use metric M7 thread rod , it is an almost perfect fit .
The finished compressor will look something like this :
the lower nut is important to prevent the bolt from turning while compressing .
The valve stop also is 2 parts : a drilled out spark plug and a bolt with a lip .
If you find an old plug with a 16 mm hex , it will be more compact :
Knock out the ceramic and centre electode ( wear eye protection ! ) and drill out .( again : a lathe is nice ..)
For the bolt , I used a bolt like pictured , it holds the front brake on the spindle on Mustangs .
Anyone familiar with old Fords will ( should ..) recognise this bolt immediately .
It has the perfect size , but of course any bolt with a large head will do , or weld the lip up .
The chamfer is very important , so that it can easily slip trough the plug hole :
total length minimum 6 cm ( 2.5" ) and lip must stick out about 8-9 mm ( 3/8 ")
Cut a slot in the top of the bolt in line with the lip .
Chamfer one end and mark the orientation of the lip ( red dot )
the bolt must be a nice sliding fit in the plug .
finished tools :
also needed :
12 mm temporary replacement rocker shaft , ' fishing ' hook , centering tool
Now to work .
first step is to remove the rocker spindle(s).
If you don't want to pull it cold , take a short ride first .
remove tank , valve cover and turn engine so that LH inlet valve is down ( to pull RH shaft )
And piston is a few mm past TDC .
Pull rocker shaft and replace with a 12mm rod ( cut bolt , drill bit ..)
Turn the engine 360° and do the other one .
Let the engine cool down if it was warm , then remove the plugs and slide loosely assembled T2 in the plug hole .
Turn the hollow plug in a few turns , turn the lip towards the valve stem and finger tighten the lock nut ;
From the inside , it will look like this :
remove the valve cover stud , using 2 nuts :
Now remove the valve adjuster and install T1
if you have mushroom adjusters , use a thin rod ( see later ) in place of the rocker shaft so that you can lift the rocker up sufficiently to remove the adjuster bolt :
Compress the valve spring .
If the retainers stick a little , a tap on the spring collar will break them loose .
Compress further , till you can remove the 2 retainers .
A magnetic screwdriver is handy .
To magnetise it , rub it over a magnet .
Remove T1 (threaded rod can be left in place )
Now , if you don't mind fidling with spring washers and shims in tight places , just remove the rocker arm completely .
If you prefer to keep the rocker arm in the head , go to the next step :
loosen T2 and turn it 180 ° so that you can lower the valve against the piston .
( it wàs a few mm past TDC , remember ? ..) :
Replace the temporary 12 mm rocker shaft with a 4 mm thin rod .
This will allow you to push the rocker just enough out of the way to remove the springs :
Once the spring is out , keep the rocker up with a rubber band , or something .
You now have free access to the seal :
Replace the seal ( No picture , I am not so crazy as to remove a perfectly good seal ..)
Reinstall spring .
Pull the valve back up , Turn T2 back 180° dir valve and tighten .
Note : If the valve has dropped too deep to catch it with pliers , remove T2 and pull it back up with a wire hook trough the plug hole .
Reinstall collar , T1 , compress , install retainers , etc ..
Here you see why it is handy to use a temporary 12 mm rocker shaft :
The spring collar will push up against the rocker arm , so you'll have to press it down a little , while centering the rocker and shims with the centering tool and than place the loose fitting 12 mm shaft .
Installing the proper rocker spindle at this stage would be difficult .
You do this best after the collar retainers are in place and T1 is removed .
Mind the correct orientation : oil hole towards the valve .
Adjust valve , remove T2 , turn engine 360° and do the other one .
Two other jobs worth considering while you are in there :
replace rocker spindle covers with one piece ones with real lip .
drill trough inlet spindles to get rid of the cross over oil line ( tough cookie : if you don't have a lathe, forget it ..) :
With the right tools you can do both seals in 2 hours easily .
It took me longer to take the pictures and type this tread ..
That's all folks .
Any questions ?
If not , happy tinkering ..