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cylinder head max lift question

  • Thread starter Thread starter jerry S
  • Start date Start date Mar 31, 2007

jerry S

New Member
Sep 3, 2003
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52.22N 5.12E
Mar 31, 2007
#1
  • Mar 31, 2007
  • #1
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

Founding Member
Sep 30, 1999
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England
Mar 31, 2007
#2
  • Mar 31, 2007
  • #2
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

Active Member
Sep 19, 2003
1,964
2
39
Middle TN
Mar 31, 2007
#3
  • Mar 31, 2007
  • #3
Coil bind and retainer to seal are the two things to check. With aftermarket heads coil bind is likely the limitation.
 

Bosscat

Founding Member
Sep 30, 1999
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0
England
Mar 31, 2007
#4
  • Mar 31, 2007
  • #4
My bad, I read that wrong. Nevermind, move along nothing to see here.
 

jerry S

New Member
Sep 3, 2003
1,365
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0
52.22N 5.12E
Mar 31, 2007
#5
  • Mar 31, 2007
  • #5
brianj5600 said:
Coil bind and retainer to seal are the two things to check. With aftermarket heads coil bind is likely the limitation.
Click to expand...

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?
 
1

10secgoal

Active Member
Dec 1, 2003
2,801
3
49
San Diego
Mar 31, 2007
#6
  • Mar 31, 2007
  • #6
jerry S said:
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?
Click to expand...

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

New Member
Sep 3, 2003
1,365
1
0
52.22N 5.12E
Mar 31, 2007
#7
  • Mar 31, 2007
  • #7
10secgoal said:
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.
Click to expand...

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.
 
8

86bluecobra

Advanced Member
Dec 20, 2004
4,265
12
69
B.C. Canada
Apr 1, 2007
#8
  • Apr 1, 2007
  • #8
I believe that your guides can be cut down (machined down) to allow the heads to use a higher lift cam.
 
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