Can someon explaine how cams affect piston-valve contact?

[BigBoy]

Do they? Also, i dont see how a valve will hit a piston if the top of the piston dome sits beneath the top of the block. Im planning to mill my b16 head about .030 which puts me at a -.001 according to c-speed.

 

[civicious]

Yes, they do. A bigger cam lobe will open your valves more, causing the valve to come closer to the head of the piston when the piston is at TDC. If you mill the head too much, and run too big of a cam, you risk smashing the valves into the head of the piston.

 

[reikoshea]

couldnt have said it better myself. In Interfearance engines (like hondas) valves and pistons occupy the same space at different times. if you have a high lift cam, the piston can smack the valve and bend it. thats what happends when a timing belt breaks...just FYI.

 

[civicious]

'interference'

 

[reikoshea]

lol, on break at work...no spell check time for reiko...i just guestimated.

 

[Dark91zc]

even on stock honda engines they are interfence engines

 

[reikoshea]

if that was a question, the answer is yes.

 

[BigBoy]

OK, im running skunk2 stage 2 cams on a b16 with 1 layer oem gasket. Its leaking right now so when i replace it, im planning on milling the head some. Will i be ok milling .030?

 

[reikoshea]

umm, i think youd be okay with a 3 layer gasket, but im gonna need someone to back me up on that.

 

[civicious]

You should be fine.

 

[olddude]

Try putting some clay (plastercine) on top of your piston , put the head on ,with a couple of bolts , and then put belt back on and turn the motor over by hand a couple of times . (Mock up )

you will see where the valves squeezes the clay and can tell where you might run into problems by checking the thickness of the clay where the valve squishes it on the piston top.

Or you could just hope for the best??

 

[civicious]

Quoted post[/post]]
I'm pretty sure that you want to use all of the head bolts torqued to proper spec for claying a motor.