Am i right in thinking you cannot do cossie stem seals with the head on as the springs are set too deep?

Paul

 

No can be done so long as you can compress the valve springs, using the nylon rope trick.
tabetha

 

explain please chris nylon rope ??? u got me interested now

Paul

 

tbh, its hardly worth the agro imo,

id be much much happier flipping its lid, and re cutting the valve seats, checking guide play etc at the same time

its only about an hours work to get the head off a yb

 

I got it down to 20 mins just wanted the know

 

mine need doing too i think, but the heads only just gone back on after a rebuild (i bought dodgy stem seals, retard!) handy to know it can be done without removing the head.

 

Just feed nylon rope into the combustion chamber through plug hole, then turn engine so the piston compresses the rope holding the valve in place, so the only cost is rope and seals instead of new gaskets, a freeze etc.
tabetha

 

Ta next question is how to compress the spring?? i can see how the rope is better that compressed air

Paul

 

That's the big question, I usually knock something up if needing to do something along these lines on a 1 off basis, but never done cossie in situ.
tabetha