Well today I got back into changing valve springs, all was going well until I got to exhaust valve on cylinder 4, I started winding bolt down to compress spring and I heard valve pop off seat and it started to pass a bit more air, I got collets off and when I put new spring on and started to compress it to get the collets on, the valve was going down as well and it would come up again when I unwound tension off the spring, I tried a couple of times then took spring off. Anyway I touched the top of the valve stem with my finger and it decided it would glide off down into the cylinder. Now I have a problem, I cant see it thru exhaust port. My engine builder said I should have had each cylinder at tdc when doing each cylinder. Was prepared to pull off head and change head bolts to arp bolts, new head gasket, but I'm gonna try turn crank slowly so piston comes up and try retrieve valve with magnet and try poke it back up valve stem first. No one told me to have each cylinder at tdc so if a valve drops it cant go far. Also if the piston is down the cylinder is a big area to fill with air and it's harder for the air to hold valve up, makes sense!! All was going so well too, damn it.