Valve guides or valve stem rubbers?

[Drewie]

We have a Blue motor 202 VC which has been in the family for 13 odd years,
around 250,000km on the clock and runs fine. However when you first start it of a morning it blows a large cloud of blue smoke, after the initial blast of smoke it may smoke slightly for maybe 30 seconds then it stops and exhaust is then clear not a trace of smoke, remainder of starts during the day are fine,
mainly when left overnight or for a few days does this happen.
I think it is either valve stem rubbers or worn valve guides, the valve stem rubbers are not as big a job as the guides but I don't want to waste time and effort in changing the rubbers to find it makes no difference and in fact it is the guides that are worn, is there anyway of checking which it might be?
Car does not use oil so I am pretty sure the rings are ok.

[immortality]

to check for wear in the valve guides you really need to remove the head and valve springs unless you have enough equipment to remove valve springs with the heads on. being as old as it is the valve stem seals are most like stuffed anyways and worth changing

[chuckie]

g`day i used valve guide oil seal`s from ford lot better seal & work`s great + ten time`s better than holden`s silly ring ,hope it help`s cheer`s chuckie.