|
06-26-2018, 01:31 PM | #11 | |
Senior Member
Join Date: Feb 2010
Posts: 505
Likes: 7
Liked 354 Times in 83 Posts
|
Re: Valve Spring Pressure - BBC stocker
Quote:
Not disagreeing with what you're saying, but if the opening ramp of the intake lobe is too close to "instantly vertical" (like what roller cam guys are using these days) the lifter can actually try to dig into the lobe and create milliseconds of valve train slack (shudder), which can cause things like valve spring surge. Even the roller cam guys admit that there is only so far you can go with "snapping" the valve open and closed. |
|
06-26-2018, 03:06 PM | #12 |
Junior Member
Join Date: Oct 2012
Posts: 81
Likes: 0
Liked 16 Times in 11 Posts
|
Re: Valve Spring Pressure - BBC stocker
Do you run with Hydrolic lifter????
How many lash you have between rochers to valves 0 or 1/4 lap |
06-26-2018, 05:44 PM | #13 |
Member
Join Date: Jan 2004
Location: Belmont N.S. Canada
Posts: 466
Likes: 224
Liked 154 Times in 68 Posts
|
Re: Valve Spring Pressure - BBC stocker
Spoke to COMP today, they are claiming that the lobe is so aggressive I need to get a different spring that is going to allow me the same open pressure, but within .050” of coil bind. He claimed that the spring is most likely doing the hokey pokey since it’s about .400” from coil bind, and not designed to work there. I thought pressure was pressure, but is this something that could actually be going on and therefore causing such an issue?
__________________
Chris Chapman 1969 Chevelle NHRA F-G/SA 1090 |
06-26-2018, 05:59 PM | #14 |
Junior Member
Join Date: Feb 2016
Posts: 45
Likes: 2
Liked 21 Times in 7 Posts
|
Re: Valve Spring Pressure - BBC stocker
|
06-26-2018, 06:32 PM | #15 | |
Senior Member
Join Date: Sep 2016
Posts: 857
Likes: 163
Liked 286 Times in 159 Posts
|
Re: Valve Spring Pressure - BBC stocker
Quote:
|
|
06-26-2018, 07:10 PM | #16 |
VIP Member
Join Date: May 2006
Location: Murfreesboro TN
Posts: 4,969
Likes: 1,136
Liked 1,218 Times in 313 Posts
|
Re: Valve Spring Pressure - BBC stocker
What valves and pushrods are you using?
__________________
Alan Roehrich 212A G/S |
06-26-2018, 07:12 PM | #17 |
Member
Join Date: Jan 2004
Location: Belmont N.S. Canada
Posts: 466
Likes: 224
Liked 154 Times in 68 Posts
|
Re: Valve Spring Pressure - BBC stocker
Ferrea Competition valves (not the hollow ones as I was told they are illegal) and trend 3/8x.120 wall pushrods
__________________
Chris Chapman 1969 Chevelle NHRA F-G/SA 1090 |
06-26-2018, 08:20 PM | #18 | |
Member
Join Date: Sep 2009
Posts: 137
Likes: 78
Liked 78 Times in 40 Posts
|
Re: Valve Spring Pressure - BBC stocker
Quote:
How far open is the valve at the point of minimal valve clearance? Is it really going to "surge" at that point in the cycle? Could it be a bounce induced from the closing cycle? |
|
06-26-2018, 08:23 PM | #19 |
Member
Join Date: Sep 2009
Posts: 137
Likes: 78
Liked 78 Times in 40 Posts
|
Re: Valve Spring Pressure - BBC stocker
|
06-26-2018, 08:33 PM | #20 | |
Member
Join Date: Sep 2009
Posts: 137
Likes: 78
Liked 78 Times in 40 Posts
|
Re: Valve Spring Pressure - BBC stocker
Quote:
|
|
|
|