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Rocker arm ratios #2530790 08/03/18 01:02 AM 08/03/18 01:02 AM
Joined: Dec 2014 Posts: 121 ky, usa littlejohn44 OP member
littlejohn44 OP member Joined: Dec 2014 Posts: 121 ky, usa	I have a set of Eddy Victor heads with Hughes offset intake rockers and crane gold exhausts. I measured at the retainer with a dial indicator on the cranes and i am getting .020 more lift than what i should be getting . Lobe lift is .410"/.414" using 1.6 rockers should be .656/.662 . I am getting .682 on the exhaust and .632 on intake. My lobes measure out with +/- .001-.002 . The cranes are stamped 1.6 but this is closer to 1.65? The hughes are closer to 1.55. I figured it might be my accuracy in measuring but they are pretty even across both sides?

Re: Rocker arm ratios [Re: littlejohn44] #2530793 08/03/18 01:06 AM 08/03/18 01:06 AM
Joined: Aug 2003 Posts: 43,172 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,172 Bend,OR USA	Originally Posted By littlejohn44 I have a set of Eddy Victor heads with Hughes offset intake rockers and crane gold exhausts. I measured at the retainer with a dial indicator on the cranes and i am getting .020 more lift than what i should be getting . Lobe lift is .410"/.414" using 1.6 rockers should be .656/.662 . I am getting .682 on the exhaust and .632 on intake. My lobes measure out with +/- .001-.002 . The cranes are stamped 1.6 but this is closer to 1.65? The hughes are closer to 1.55. I figured it might be my accuracy in measuring but they are pretty even across both sides? And your question is? Last edited by Cab_Burge; 08/03/18 01:06 AM. Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Rocker arm ratios [Re: littlejohn44] #2530813 08/03/18 02:45 AM 08/03/18 02:45 AM
Joined: Jan 2003 Posts: 31,029 Oregon A AndyF I Win
AndyF I Win A Joined: Jan 2003 Posts: 31,029 Oregon	Are you using real springs or checking springs?

Re: Rocker arm ratios [Re: AndyF] #2530853 08/03/18 10:31 AM 08/03/18 10:31 AM
Joined: Mar 2003 Posts: 9,099 Rogue River, OR Jeremiah master
Jeremiah master Joined: Mar 2003 Posts: 9,099 Rogue River, OR	...because if you are using checking springs the rocker arm manufactures build in extra ratio to compensate for deflection. It is typical to see artificially high lift numbers at the valve with a light checking spring. Signed, apt pupil

Re: Rocker arm ratios [Re: littlejohn44] #2530854 08/03/18 10:33 AM 08/03/18 10:33 AM
Joined: Jan 2003 Posts: 14,497 So. Burlington, Vt. F fast68plymouth I Live Here
fast68plymouth I Live Here F Joined: Jan 2003 Posts: 14,497 So. Burlington, Vt.	My one experience with Hughes rockers, and it was the older version without the slot down the middle....... Std offset BB rockers, EZ heads, 1.6 ratio.....just under 1.6 with a checking spring, about 1.51-1.52 with 600lbs of spring load. My experience has been that Cranes are usually about .05 higher than advertised when measured with a checking spring. 68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads

Re: Rocker arm ratios [Re: littlejohn44] #2530918 08/03/18 12:29 PM 08/03/18 12:29 PM
Joined: Jun 2008 Posts: 3,916 usa L lewtot184 master
lewtot184 master L Joined: Jun 2008 Posts: 3,916 usa	the crane 1.6's I've measured were 1.65. there are some variables but all the cranes I've checked had ratios higher than their rating.

Re: Rocker arm ratios [Re: fast68plymouth] #2531029 08/03/18 03:53 PM 08/03/18 03:53 PM
Joined: Dec 2014 Posts: 121 ky, usa littlejohn44 OP member
littlejohn44 OP member Joined: Dec 2014 Posts: 121 ky, usa	Originally Posted By fast68plymouth My one experience with Hughes rockers, and it was the older version without the slot down the middle....... Std offset BB rockers, EZ heads, 1.6 ratio.....just under 1.6 with a checking spring, about 1.51-1.52 with 600lbs of spring load. My experience has been that Cranes are usually about .05 higher than advertised when measured with a checking spring. That's about what I'm getting. I am not using checking springs. I have checked them 10 times each thinking I was crazy. I am using the old style Hughes also would have figured they would be s little more accurate since not produced on a scale as large as cranes.

Re: Rocker arm ratios [Re: littlejohn44] #2531046 08/03/18 04:19 PM 08/03/18 04:19 PM
Joined: Oct 2007 Posts: 4,206 New York polyspheric master
polyspheric master Joined: Oct 2007 Posts: 4,206 New York	The rocker ratio will vary slightly over the length of travel. The stated ratio may have been with a specific lobe height. Boffin Emeritus

Re: Rocker arm ratios [Re: littlejohn44] #2531285 08/03/18 11:54 PM 08/03/18 11:54 PM
Joined: Dec 2014 Posts: 121 ky, usa littlejohn44 OP member
littlejohn44 OP member Joined: Dec 2014 Posts: 121 ky, usa	I was using the way Hughes suggests for measuring for new push rods when i figured this out. If i multiply the lobe lift by the ratio on the cam card it comes out to what they are calling the lift numbers. That just blows my mind, that they could be off. Kinda hard to pick out a cam when you are relying on ratios to be true.

Re: Rocker arm ratios [Re: littlejohn44] #2531536 08/04/18 04:12 PM 08/04/18 04:12 PM
Joined: Aug 2003 Posts: 43,172 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,172 Bend,OR USA	I've check a bunch of different rocker arms for ratio at the retainers, even the good ones will vary some in the same set I've seen T&D single shaft sets vary .030 at the retainers, same on some of the older Harland Sharp sets. The older ductile iron sets sold by all of the cam company are horrible also, same on the extruded aluminum sets Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

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