Rocker Arm Ratio

Wade_Owens · 07-19-2012, 07:33 PM

PJ, I heard the rocker ratio was dropped too. I called Travis and he said it was still in full effect. He was the one who checked them at the Allstars this year. Lift at valve as well as ratio will be enforced.

Wade O

Jeff Teuton · 07-20-2012, 09:11 AM

If your rocker has no number (ratio) stamped on it, don't worry about it. I was thrown out because mine were stamped 1.65 and the rules said 1.60. The cam checked ok. Without the numbers nobody knows or cares I think.

Alan Roehrich · 07-20-2012, 09:17 AM

They can, and will, check lift at the valve, and then lift at the cam. From that they will check rocker arm ratio. If the ratio is greater than what is in the blueprint specs, they will throw you out.

Feel free to ask Travis Miller, or Dave Ley about this, they will explain it to you. There are also several threads on the subject that explain why and how about rocker ratio. I have seen people thrown out for rocker ratio.

Marine One · 07-20-2012, 11:41 PM

Rocker ratio is not constant in the swing of the arc. Check max lift at the valve and at the cam all you want and you will never catch it that way, unless you went crazy and tried to go from something like 1.6 to 1.8

RULER · 07-21-2012, 03:06 AM

If they check lobe lift and x it by the correct ratio it better be the same or damn close to what it checks at the valve, you will always loose some from spring pressure but not the difference between 1.5 and 1.6, but when was the last time they checked lobe lift ? and is that something there doing now ?

Charley Downing · 08-03-2012, 03:57 PM

As per Danny and Bruce at Chicago nationals this year any ratio is allowed.
Dalles Glens corvette had 1.55 rockers from comp cams on his lt1 corvette and 1.5 is the spec .Danny told me all NHRA cares about is that the cam checks
And that is fact.

PJ305 · 08-03-2012, 04:22 PM

Charley,

Wade O. said Travis checked all the rocker ratio's at Chicago so how could Dallas Glenn be legal with 1.55 rockers when 1.50 are in the blueprint spec.
Travis can you clear this up for the guys going to Indy.

Thanks

07-19-2012, 07:33 PM	#1
Wade_Owens Senior Member Join Date: Jul 2007 Posts: 578 Likes: 0 Liked 3 Times in 1 Post	Re: Rocker Arm Ratio PJ, I heard the rocker ratio was dropped too. I called Travis and he said it was still in full effect. He was the one who checked them at the Allstars this year. Lift at valve as well as ratio will be enforced. Wade O

07-20-2012, 09:11 AM	#2
Jeff Teuton VIP Member Join Date: Jan 2002 Location: Houma, LA Posts: 2,717 Likes: 2 Liked 325 Times in 50 Posts	Re: Rocker Arm Ratio If your rocker has no number (ratio) stamped on it, don't worry about it. I was thrown out because mine were stamped 1.65 and the rules said 1.60. The cam checked ok. Without the numbers nobody knows or cares I think. __________________ Jeff Teuton 4022 STK

07-20-2012, 09:17 AM	#3
Alan Roehrich Veteran Member Join Date: May 2006 Location: Murfreesboro TN Posts: 5,125 Likes: 1,583 Liked 1,880 Times in 422 Posts	Re: Rocker Arm Ratio They can, and will, check lift at the valve, and then lift at the cam. From that they will check rocker arm ratio. If the ratio is greater than what is in the blueprint specs, they will throw you out. Feel free to ask Travis Miller, or Dave Ley about this, they will explain it to you. There are also several threads on the subject that explain why and how about rocker ratio. I have seen people thrown out for rocker ratio. __________________ Alan Roehrich 212A G/S

07-20-2012, 11:41 PM	#4
Marine One Junior Member Join Date: Mar 2010 Location: Indiana Posts: 69 Likes: 2 Liked 0 Times in 0 Posts	Re: Rocker Arm Ratio Rocker ratio is not constant in the swing of the arc. Check max lift at the valve and at the cam all you want and you will never catch it that way, unless you went crazy and tried to go from something like 1.6 to 1.8 __________________ Chad Sheets \| STK 319 \| 10.69 \| 1.39 Last edited by Marine One; 07-20-2012 at 11:46 PM.

07-21-2012, 03:06 AM	#5
RULER Member Join Date: Jan 2006 Posts: 222 Likes: 15 Liked 58 Times in 18 Posts	Re: Rocker Arm Ratio If they check lobe lift and x it by the correct ratio it better be the same or damn close to what it checks at the valve, you will always loose some from spring pressure but not the difference between 1.5 and 1.6, but when was the last time they checked lobe lift ? and is that something there doing now ?

08-03-2012, 03:57 PM	#6
Charley Downing Senior Member Join Date: Sep 2007 Posts: 762 Likes: 16 Liked 653 Times in 89 Posts	Re: Rocker Arm Ratio As per Danny and Bruce at Chicago nationals this year any ratio is allowed. Dalles Glens corvette had 1.55 rockers from comp cams on his lt1 corvette and 1.5 is the spec .Danny told me all NHRA cares about is that the cam checks And that is fact. __________________ Charley Downing 3548 STK Last edited by Charley Downing; 08-03-2012 at 04:00 PM.

08-03-2012, 04:22 PM	#7
PJ305 Member Join Date: Jul 2007 Posts: 137 Likes: 0 Liked 5 Times in 4 Posts	Re: Rocker Arm Ratio Charley, Wade O. said Travis checked all the rocker ratio's at Chicago so how could Dallas Glenn be legal with 1.55 rockers when 1.50 are in the blueprint spec. Travis can you clear this up for the guys going to Indy. Thanks

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