Bmw m51

Hello does anyone have the specs for the valves and any settings relating to the BMW m51 . I'm fairly certain that once mine is hot the valves are not fully closing suggesting my valves and seats have worn a bit and needs some sort of adjustment or is it a case of new valves and seats because there is no adjustment there . Any help would be greatly appreciated regards Dean

Clearances are automatic. If your valves were not closing you would know about it as they made love to the pistons. If the valves are not sealing only thing is to remove head and service them. What makes you think they are not closing?

It's fine when it's cold but when it's hot it's nowhere near the same power and it takes a few turns before it starts .it's a different head as the old one cracked and it's never been same since once it's hot also when it's hot and you turn it by hand you can hear the valves hiss as they leak .

Every engine I have ever turned over by hand hisses.

The hissing seems normal to me, you can normally hear air hiss as you rotate an engine by hand.

Rich

Well got to the bottom of my m51 power issues and oil leaks it was a restriction in the engine breather it didnt affect it at idle and it appeared to breath as you would expect but underload and on boost the breathing increases in a big way and that s where my trouble was its also cured my running hot issues too . I wouldnt mind but ive power washed the cam cover a few times and purposely done the breather and never got much yak out of it but there you go you live n learn .