I've got a 72 240Z that needs the valve seals replaced. The engine has 75K since a rebuild including head work this was done 15 years ago so age has taken its toll on the seals. 6 years ago the I removed the heads to replace a broken head bolt inspected the heads. They were still in good shape no warping and not much carbon. However I SHOULD have checked the valve seals and replaced them but thats hind sight. I did put in new Turbo head bolts. Any way back to the present, Compression and leak down are are good so my question is does any one have any great way to replace the valve seals without removing the head?
My current idea is to remove the cam on the car and put the piston to TDC, put compressed air into the cylinder(not too much, with the car in gear and hand brake on) and use a some form of valve spring compressor. Now I know Motot Sport has such a tool however at $145 a copy I would just as well remove the head and use a standard valve spring compressor, a few more hours work but what a bargain in comparison. I'm probably end up removing the head but I thought I throw this out and see if anyone has done it!

 

I done it, it's a pain. When I did mine, I had everything right til I hooked the compressor without the cam(I was changin the cam too) loose from the timing chain. it span and I ended up with whole front cover off. But even with cam attached, if you don't have the right tool it's not a easy process.