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valve rocker arms (Read 1545 times)
Nov 28th, 2011 at 6:52pm

vics71   Offline
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Bainbridge Island Washington

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Curious if anyone can tell me when refering to rocker arms I see 1.5 or 1.6 ratio listed. What ratio is this refering to exactly?
Victor
 
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Reply #1 - Nov 28th, 2011 at 7:29pm

Redwingvette   Offline
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Waterford, Michigan

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The ratio is a multiplier of sorts. Most cam information for a SBC is listed with a 1.5 ratio rocker. If the cam list a lift .480 then with a 1.5 ratio rocker the valve will open .480 but the actual lift on the cam lobe is only .320. Now if you change the rocker ratio to a 1.6 then the actual lift of the valve will increase to .512. Some people will choose to change the rockers because it will be cheaper then changing the cam to get more lift. If you are changing the cam anyway then it is better to buy the cam with the lift you want. Just changing the rockers can lead to other issue. You should always change the lifters and push rods when changing the cam. If you just change the rockers you will need to make sure the 1.6 rockers fit under your valve covers and the push rods do not start hitting the side walls of the heads.
 

Brian
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Reply #2 - Nov 28th, 2011 at 8:54pm

vics71   Offline
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Bainbridge Island Washington

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Thanks!! I'm starting an engine project and gathering parts and information.
Vic
 
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Reply #3 - Nov 29th, 2011 at 6:16am

TX 73 gone   Offline
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Real good info Brian.

Charlie
 

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Reply #4 - Nov 29th, 2011 at 7:49am

Artsvettes   Offline
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New Jersey

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The single most inportant thing to remember when changing rocker arm ratio. Is checking the clearence between the Valve stem seal to valve retainer. And clearence between valve and piston. Or things will get ugly real fast...............jack
 

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