Rocker Geometry

Scott Foxwell wrote:

Lem Evans wrote:

Scott Foxwell wrote:

Lem Evans wrote:I'm not much on theory but, I like a sweep that is near the center of the stem and the most narrow.

I agree, although you seldom get both. I look for the narrowest pattern which is going to be closest to the 90* @ half lift geometry method. IMO where the roller tip sits on the valve is secondary.

Getting both has not been that big of a deal on the TFS A460 heads........using a Crower S.S. rocker and a standard [non-bastard] lenght valve.

Someone did their homework, but not a surprise with Crower. It's frustrating to have to go through three or four different sets (brands) of rockers...all supposedly for the same application...to find one that works correctly. I've found that for BB Chev's (pardon the reference..lol) the Crane Gold is about the only one, so far, that "works". I know Crower offers rockers that are set back to help correct the "tall valve, off-center roller" syndrome, but as long as the roller is not much further than the outside third of the valve (or so) I don't worry too much about it...long as the geometry is right. Canfield even stated in their literature that their heads were designed around a Cranae Gold rocker. It's also why I suggest Scorpion race series these days...they supposedly took up the Crane design. They look very similar and the last set I did worked out well.

Lem Evans wrote:Not having a queer rockerarm is a very big deal to me. I only use the Cower s.s./crane gold/frpp blue[also crane] rockers. I'm sure there are others than will be just fine.....I'm just looking for things to repeat [predictable] with on track results.
I.m.o. a guy could split every hair there is to split on this roller on the tip thang and put a cheap assed pushrod in the engine and still not have much.I'm not very smart but I make up for it by being stupid.

rmcomprandy wrote:

Scott Foxwell wrote:

Lem Evans wrote:

Scott Foxwell wrote:

Lem Evans wrote:I'm not much on theory but, I like a sweep that is near the center of the stem and the most narrow.

I agree, although you seldom get both. I look for the narrowest pattern which is going to be closest to the 90* @ half lift geometry method. IMO where the roller tip sits on the valve is secondary.

Getting both has not been that big of a deal on the TFS A460 heads........using a Crower S.S. rocker and a standard [non-bastard] lenght valve.

Someone did their homework, but not a surprise with Crower. It's frustrating to have to go through three or four different sets (brands) of rockers...all supposedly for the same application...to find one that works correctly. I've found that for BB Chev's (pardon the reference..lol) the Crane Gold is about the only one, so far, that "works". I know Crower offers rockers that are set back to help correct the "tall valve, off-center roller" syndrome, but as long as the roller is not much further than the outside third of the valve (or so) I don't worry too much about it...long as the geometry is right. Canfield even stated in their literature that their heads were designed around a Cranae Gold rocker. It's also why I suggest Scorpion race series these days...they supposedly took up the Crane design. They look very similar and the last set I did worked out well.

The CRANE rocker arms are designed using the 2/3 lift principal, (at least that is according to what Harvey Crane says), and that is also just one of MANY principals in existence for valve train geometry.