stamped steel rocker arm delection

gmonde · 02-01-2011, 09:47 PM

just seeing the results you guys are getting on how much lift are you loosing on your stock steel rockers ?? with 220 lbs on the seat ,i see a sizable loss between the difference against measuring with a checking spring and these rockers are not cryoed these a 1.6 ratio rockers gmonde

Alan Roehrich · 02-01-2011, 09:58 PM

I've never been able to measure it or verify it. I'd say you'd just about have to do it on a Spin Tron to accurately measure it.

Try checking a roller rocker the same way.

gmonde · 02-01-2011, 10:22 PM

alan,i am sure the a roller rocker will not loose as much if not anything ,i guess i didnt realize how much of the actual lift you mite not be using with the actual valve spring load to get the maximum lift you are required,checking the lift at the retainer with a checking spring vs the actual valve spring is sizable difference gmonde

Grant Eldridge · 02-02-2011, 02:33 AM

The deflection I've measured is about .015" from checking spring to race springs on my 396 stocker motor. This is a combination of the pushrod flex, rocker stud flex and the rocker arm itself, not sure how you'd isolate the amount in the rocker alone but it is significant. NHRA checks lift at the retainer, using a solid lifter of the same height, so you can adjust the lobe lift to compensate for the loss from what I understand....

greg fulk · 02-02-2011, 02:55 AM

I have .006 extra ground into lob lift to get closer to max lift on the 6cyl engines.

gmonde · 02-02-2011, 09:29 AM

Quote:

Originally Posted by Grant Eldridge

The deflection I've measured is about .015" from checking spring to race springs on my 396 stocker motor. This is a combination of the pushrod flex, rocker stud flex and the rocker arm itself, not sure how you'd isolate the amount in the rocker alone but it is significant. NHRA checks lift at the retainer, using a solid lifter of the same height, so you can adjust the lobe lift to compensate for the loss from what I understand....

grant:how much spring presure are you running??i know big blocks have a 3/8 push rod but you probably run a 7/16" or 1/2" and the ratio is 1.7 ,,.015 is not bad i am getting more ..020 -.025 and thats with a 3/8 push rod gmonde

Wade_Owens · 02-02-2011, 10:35 AM

Keep in mind, your lift values change as you lose race spring pressure, too.

Wade

Wade_Owens · 02-02-2011, 10:37 AM

[QUOTE=Grant Eldridge;237444]The deflection I've measured is about .015" from checking spring to race springs on my 396 stocker motor. QUOTE]

Grant, sometimes it can be WAY more difference than that. I learned the hard way on this too. Never use checking springs, use the race springs at the pressure your going to run to be accurate.

Wade

Grant Eldridge · 02-02-2011, 11:35 AM

gmonde, I run 240 on the seat, 440 open pressure.
wade, I was surprised how much deflection there is in these parts. When I ran the stock size studs you could see them bend turning over the motor! I have since gone to Clark Holroyd's nice stainless thick studs and rockers, but still have deflection.....Clark now welds a re-inforcement onto his rockers above the pushrod seat, like a small bridge across, that might further help....

gmonde · 02-02-2011, 11:48 AM

Quote:

Originally Posted by Grant Eldridge

gmonde, I run 240 on the seat, 440 open pressure.
wade, I was surprised how much deflection there is in these parts. When I ran the stock size studs you could see them bend turning over the motor! I have since gone to Clark Holroyd's nice stainless thick studs and rockers, but still have deflection.....Clark now welds a re-inforcement onto his rockers above the pushrod seat, like a small bridge across, that might further help....

is welding a brace on the rocker legal in stock??? hhmmmm gmonde

02-01-2011, 09:47 PM	#1
gmonde Senior Member Join Date: Nov 2007 Posts: 615 Likes: 56 Liked 165 Times in 59 Posts	stamped steel rocker arm delection just seeing the results you guys are getting on how much lift are you loosing on your stock steel rockers ?? with 220 lbs on the seat ,i see a sizable loss between the difference against measuring with a checking spring and these rockers are not cryoed these a 1.6 ratio rockers gmonde

02-01-2011, 09:58 PM	#2
Alan Roehrich Veteran Member Join Date: May 2006 Location: Murfreesboro TN Posts: 5,068 Likes: 1,507 Liked 1,648 Times in 379 Posts	Re: stamped steel rocker arm delection I've never been able to measure it or verify it. I'd say you'd just about have to do it on a Spin Tron to accurately measure it. Try checking a roller rocker the same way. __________________ Alan Roehrich 212A G/S

02-01-2011, 10:22 PM	#3
gmonde Senior Member Join Date: Nov 2007 Posts: 615 Likes: 56 Liked 165 Times in 59 Posts	Re: stamped steel rocker arm delection alan,i am sure the a roller rocker will not loose as much if not anything ,i guess i didnt realize how much of the actual lift you mite not be using with the actual valve spring load to get the maximum lift you are required,checking the lift at the retainer with a checking spring vs the actual valve spring is sizable difference gmonde

02-02-2011, 02:33 AM	#4
Grant Eldridge Member Join Date: Jul 2007 Posts: 124 Likes: 0 Liked 0 Times in 0 Posts	Re: stamped steel rocker arm delection The deflection I've measured is about .015" from checking spring to race springs on my 396 stocker motor. This is a combination of the pushrod flex, rocker stud flex and the rocker arm itself, not sure how you'd isolate the amount in the rocker alone but it is significant. NHRA checks lift at the retainer, using a solid lifter of the same height, so you can adjust the lobe lift to compensate for the loss from what I understand....

02-02-2011, 02:55 AM	#5
greg fulk VIP Member Join Date: Jan 2003 Location: jackson Posts: 1,165 Likes: 0 Liked 5 Times in 3 Posts	Re: stamped steel rocker arm delection I have .006 extra ground into lob lift to get closer to max lift on the 6cyl engines. __________________ Greg Fulk 308 308X P/SA "ALL AMERICAN"

02-02-2011, 10:35 AM	#7
Wade_Owens Senior Member Join Date: Jul 2007 Posts: 578 Likes: 0 Liked 3 Times in 1 Post	Re: stamped steel rocker arm delection Keep in mind, your lift values change as you lose race spring pressure, too. Wade Last edited by Wade_Owens; 02-02-2011 at 10:38 AM.

02-02-2011, 10:37 AM	#8
Wade_Owens Senior Member Join Date: Jul 2007 Posts: 578 Likes: 0 Liked 3 Times in 1 Post	Re: stamped steel rocker arm delection [QUOTE=Grant Eldridge;237444]The deflection I've measured is about .015" from checking spring to race springs on my 396 stocker motor. QUOTE] Grant, sometimes it can be WAY more difference than that. I learned the hard way on this too. Never use checking springs, use the race springs at the pressure your going to run to be accurate. Wade

02-02-2011, 11:35 AM	#9
Grant Eldridge Member Join Date: Jul 2007 Posts: 124 Likes: 0 Liked 0 Times in 0 Posts	Re: stamped steel rocker arm delection gmonde, I run 240 on the seat, 440 open pressure. wade, I was surprised how much deflection there is in these parts. When I ran the stock size studs you could see them bend turning over the motor! I have since gone to Clark Holroyd's nice stainless thick studs and rockers, but still have deflection.....Clark now welds a re-inforcement onto his rockers above the pushrod seat, like a small bridge across, that might further help....