Valve seals - changed in situ

[Purple_rob]

Can this be done?. Is there a tool out there to compress the springs with the head on?.

I know there is for fords/Vauxhalls as I used to change quite a few by putting the piston to TDC and popping the spring off.

[car.crash]

we have done it, but its a ball ache.
remove plugs, long flat head screwdriver thats bent to hold valve up, then you have to compress the valve spring.

[TNT!hammond]

There is a tool that allows compressed air to be pumped into the cylinder causing the valve to be held up, only prob is if the valve isnt seated right you could get leakage and then the valve will drop.

Aswell as that tool there is one that levers off the rocker assembly to compress the springs. I thought about doing this for all of ten minutes then just whipped the head off in the next 20 min hahah