cylinder head max lift question

[jerry S]

My heads come with the specifications of a max valve lift of .575 but I want to put in a cam with a max valve lift of .576. What exactly is this limitation a function of? I am changing out the springs, retainers, and valves anyway. Is there anyway to get around this?

 

[Bosscat]

Think of it this way, when the cam has the valve at full lift, where is the piston? Near the bottom of the bore. The biggest issue is with the ramp rate, and duration

 

[brianj5600]

Coil bind and retainer to seal are the two things to check. With aftermarket heads coil bind is likely the limitation.

 

[Bosscat]

My bad, I read that wrong. Nevermind, move along nothing to see here.

 

[jerry S]

Coil bind and retainer to seal are the two things to check. With aftermarket heads coil bind is likely the limitation.

Is the max lift a function of the springs and retainers? If so, would swapping out the springs and retainers for something else provide for a different max lift?

 

[10secgoal]

Is the max lift a function of the springs and retainers? If so, would swapping out the springs and retainers for something else provide for a different max lift?

Yes. That is when you start to see coils springs change. Going to a double or triple spring to retain same force, but thinner so no coil bind.
I don't know that I would worry about .001 though. You can chrck yourself if you wanted.

 

[jerry S]

Yes. That is when you start to see coils springs change. Going to a double or triple spring to retain same force, but thinner so no coil bind.
I don't know that I would worry about .001 though. You can chrck yourself if you wanted.

I was actually thinking about going with a single beehive spring. I will discuss with the guys who will be porting my heads. I just wanted to inform myself in advance of that discussion so I could know a few buzzwords and pretend like I had an inkling of a clue about what I was talking.

 

[86bluecobra]

I believe that your guides can be cut down (machined down) to allow the heads to use a higher lift cam.