Jesel Rockers

[Mike Rogers]

Has any one seen the ratio of the rocker arms off on Jesel shaft rockers.I,am do the cam checks for the Hooters engine i,am building and we must have .625 lift with no lash.The cam lift is .347 rocker ratio 1.8
should come up .6246 at the valve.What i,am getting is .640 lift at the valve tryed both sides of engine #1 and #6 with two diffrent rockers.This is on the intake side.Ex. side is the same but with a 1.7 rocker and cam lift of .367 i get valve lift of .633 with 0 lash.

[shawn]

Ahhhhhhhhh, the old closely guarded Jesel secret. The rockers are actually more ratio than they advertise. I ran across the same thing and called to ask them why my lift at the valve was so different than what is was suppose to be. They told me most all of their rockers have about .05 more in the ratio than advertised, for deflection and other things. I thought i was doing something wrong, too!If you add the .05 to the advertised ratio, you'll see what i mean.
Shawn

[idunno]

Did you check the lobe lift on the cam yourself?

[Mike Rogers]

Yes i,am an engine machine shop.

[idunno]

Then the ratio's have to be incorrect like you suspected.Any Geometry issues would only reduce lift at the valve as well as pushrod angles.

[BRENT FAY]

When I would need shaft rockers for a head that no one made yet I would call W.W. Engineering in Georgia to make up rockers. He would want specs of head and ratio needed and would ask what lash you were going to run and he would build the lash into the ratio so net lift would be whatever ratio times lobe lift. ex. 1.8 x .450 = .810 valve opening with lash set. Wilfred made some nice stuff. He wasnt to far from the Elliots or W.J. which he did alot of prototype development work for those guys. Brent

[ALKYBURNER]

how do we get a hold of the phone number for WW engineering

[rmbuilder]

The number is:
(706) 216-8388
Bob

[idunno]

his name id Williford Boutalier,w.w. stands for Wild Williford

[OldSStroker]

Has any one seen the ratio of the rocker arms off on Jesel shaft rockers.I,am do the cam checks for the Hooters engine i,am building and we must have .625 lift with no lash.The cam lift is .347 rocker ratio 1.8
should come up .6246 at the valve.What i,am getting is .640 lift at the valve tryed both sides of engine #1 and #6 with two diffrent rockers.This is on the intake side.Ex. side is the same but with a 1.7 rocker and cam lift of .367 i get valve lift of .633 with 0 lash.

.347 lift lobes, like Comp's TK Lift Rule lobes assume exact 1.8 ratios. Same thing for .367 CR Lift Rule lobes. Depending on the rocker geometry, rocker ratios vary from valve closed to full open. Obviously the full open ratio is critical in your engine. The "1.8" is about 2.5% and the "1.7" about 1.5% high using your numbers. Not much, but critical if Hooters tech guys really check.

You are checking with full valve spring pressure I assume. Even a very stiff rocker deflects a measurable amount under valve open spring loads.

What do other Hooters builders run for rockers? If Jesel is the preferred brand, perhaps Jesel has slightly special "1.8s" and "1.7s" just for Hooters engines. They machine most of their stuff in house, I believe, so varying the ratio a bit should be easy.

You can't be the only builder in this prediciment.

[Adger Smith]

With the stands set at the correct height to get rocker contact correct at the valve stem shorten the pushrod & turn the rocker adjuster more turns out to reduce the ratio.

[Mike Rogers]

I order a set of 1.75 and 1.65 and we will see if that fixes the problem it should.

Thanks for every ones help

[Mike Rogers]

Just wanted to share what i found.I order 2 rocker arms with .5 less ratio than what i had and it reduced the lift to ware i need it .625.So it seems even with the major companys they add .5 extra in ratio to there rockers due to flex in the arm itself and the push rod most pople would not care about the extra lift but i have a rule to work with.



Thanks all for your help

[Adger Smith]

Mike,
Take the original rockers and set then up with the adjuster cup out of the rocker seat by 2 1/2 turns. this will require shorter pushrods. The rocker ratio is set at 1 1/2 turns out of the cup seat. It will reduce the ratio because of the placement angle of the adjuster cup. It pulls the adjuster cup away from the fulcrum, making the ratio smaller. I could go on,--- if you want more call (903) 794-7223

[k-star]

Mike,
Take the original rockers and set then up with the adjuster cup out of the rocker seat by 2 1/2 turns. this will require shorter pushrods. The rocker ratio is set at 1 1/2 turns out of the cup seat. It will reduce the ratio because of the placement angle of the adjuster cup. It pulls the adjuster cup away from the fulcrum, making the ratio smaller. I could go on,--- if you want more call (903) 794-7223

Adger, is there a calculated amount that the ratio changes by that you can figure the length of push rod you need in relation to needed rocker ratio?????

thanks ,Keith