I've pieced together a bit of info from searching then there's this... these threads have been very useful: http://www.aus300zx.com/forum/showthread.php?t=326269 http://www.aus300zx.com/forum/showthread.php?t=285791 but i'm still a bit stumped. so put simply I'm curious about which (if any) cams can be dropped in with the motor + heads still in the car. If there are cams that are happy to do this, would a thinking man would use them? or does the defining factor that allows them to be "drop ins" limit their effectiveness? Of course it is wiser to set this all up as the engine is assembled, but what drawbacks are faced installing them later? Lastly, for machining necessary, can it be done safely (again, would a smart man) with heads in-situ? i.e removing a small amount of material with a dremel versus line honing. I have JUN valve springs and BDE series 1 intake gears, though the latter can be exchanged if necessary. Bottom end is currently being assembled and head work has not begun, currently intending to use S1 manual cams. I think I am leaning towards the JUN 264/9.5 cams but am flexible. Cheers. -A
Put simply no. When going big lift you EITHER need to make room in the heads for bigger cams OR reduce the base of the cam which has the flow on effect of reducing pre load on the lifter. The 9.5mm/.264 cams you mentioned will require the heads be machined to accommodate them.
Possible to mechine them before assembly? Then you can drop them later on. Or would guessing how much needs to be removed be to difficult?
Just machine with a due grinder -not much needs to come off and it doesn't need a great deal of precision.
The head is simply given clearance to allow for the larger lobe, a small amount of the casting is grinded away.
Oh that's all! That could easily be done with heads still on the car and a dremel. Obviously with a stupid amount of rags and tape everywhere to catch the shrapnel.
