Hi im trying to do a valve job and i cant loosen the jam nuts they are to tight and i dont want to put to much force on them are they suppose to be this tight?
Yes they are on very tight as far as i know when i do mines. Make sure that when u use the tool(s) that they are snug and not stripped or any signs of worn/wears.
Just take ur time and try using a 2ft bar that u can use as leverage, and remember dont hurt urself when trying to turn them loose while sometimes ur hands can go flying into the studs or other areas if the tool comes off the nut.
As far as being so tight i believe they have to be due to heat expanding when engine is hot and cold so overtime it gets very tight in there otherwise if it wasnt tight i would be scare to drive it if its not tq down to specs.