roller rocker ratio - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 07-22-2012, 10:47 AM
Registered User
 
Join Date: Oct 2010
Location: united kingdom
Posts: 174
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
roller rocker ratio

Hi Guys
Finally got around to removing my camel humps,replacing them with some aluminium heads 64cc 210 runners,my cam is a 280 magnum 480 480 lift,would I benefit from replacing 1:5 rockers with some 1:6 rockers(resulting in a 510 510 lift)I was told the 210cc runners are too big for my setup?
+60 sbc,rpm intake,flat tops,600 holley.
Any imput would be great?

Last edited by dave350v8; 07-22-2012 at 10:53 AM.
Reply With Quote
  #2 (permalink)  
Old 07-22-2012, 11:37 AM
327NUT's Avatar
Registered User
 
Last photo:
Join Date: Dec 2004
Location: So. Utah
Age: 66
Posts: 3,076
Wiki Edits: 0

Thanks: 0
Thanked 36 Times in 32 Posts
Totally up to you but unless you're racing around your streets at 6,000 rpm you'll never notice the difference.
Reply With Quote
  #3 (permalink)  
Old 07-22-2012, 01:01 PM
F-BIRD'88's Avatar
Yada Yada Yada
 
Last photo:
Join Date: Oct 2005
Location: Ontario, Canada
Posts: 8,163
Wiki Edits: 0

Thanks: 0
Thanked 175 Times in 173 Posts
The difference will be small. You'll see more WOT power gain by upgradeing the
600cfm carb to a 750 cfm carb.
The 210cc heads are not too big. But now the carb is marginally a bit too small for max performance.

Generally higher ratio rockera re much more effective on the intake side than the exhaust side on a SBC. and generally especially if the intake cam lobe is smaller than the exhaust. the 1.6 in and 1.5 ex evens out the valve lift.

EG: say you had a cam with 219 deg in and 230 ex @.050"
.462" in .480" ex

The 1.6 intake rocker would give you .492" intake valve lift and more intake valve open area and lift with the same intake seat duration. (faster valve action+ more valve lift, within the same {short} valve open duration)
This tends to improve power especialy on ported or aftermarket heads that like higher valve lift to flow more.

The exhaust side (on a SBC) responds much more to valve duration and LSA changes to move the exhaust open close events around.
Thus the 1.6 in 1.5 rocker combo.

Your cam is still undersized so you would see a much more gain from simply changing the camshaft rather than rocker ratio.
Especially with the new high flow heads.

you can try your rocker wap but the only way to actually see if it makes a real difference is to track test it
A -B with the 1.5 rockers. The higher the rocker ratio the more critical the valvetrain control @high rpm (valvesprings)

Last edited by F-BIRD'88; 07-22-2012 at 01:08 PM.
Reply With Quote
  #4 (permalink)  
Old 07-22-2012, 03:16 PM
Registered User
 
Join Date: Oct 2010
Location: united kingdom
Posts: 174
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Thanks for your replies,think I will run it down the strip see how it performs,hopefully runs quicker than the camel humps! May look at swapping the cam then,just bought some howards retro roller lifters for a future build! so i might use them with a good roller cam. always felt that the camels were holding back on the top end,or the 600 hollley. Thanks F-BIRD for your detailed advice!
Reply With Quote

Recent Engine posts with photos


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Roller Rocker vs. Roller Tip Rocker Ozz1967 Engine 15 01-08-2008 04:53 AM
roller rocker ratio. Super Chevy Engine 2 01-09-2004 06:07 PM
1.7 ratio roller rocker on a SBC 383vette Engine 1 10-15-2003 10:15 AM
rocker ratio 70 nova Engine 1 05-10-2003 08:12 AM
roller rocker ratio? Thacolbster Engine 4 02-05-2003 03:36 AM


All times are GMT -6. The time now is 02:28 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2013, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.