Roller Rockers in Rv8 Engine
Discussion
Getting fed up with adjusting the pushrods to set the valve clearances and the alternatives are a set of yella terra roller rockers or John Eales adjustable rockers, both around the same price.
roller rockers look to have advantages in less stress on the valve train, but equally nave more moving parts so something else to break.
does anyone have any experience of using yella terra rockers. I have the rocker shaft mounts with end posts
if i did go yella terra it would probably be the kit that fits stock shafts rather than their full kit with bespoke shafts and mounts
roller rockers look to have advantages in less stress on the valve train, but equally nave more moving parts so something else to break.
does anyone have any experience of using yella terra rockers. I have the rocker shaft mounts with end posts
if i did go yella terra it would probably be the kit that fits stock shafts rather than their full kit with bespoke shafts and mounts
It's when the tip of the roller rolls across the top of the valve stem. If it rolls across the valve correctly it won't push the valve sideways which can cause premmature wear or failure. Usually you have to raise the rocker pedastal using shims or sometimes machine the undersides to lower the pedastal.
phazed said:
I have the Yella Terras fitted to my chim.
It was pretty straightforward to check the throw of the rockers over the valvestem. I can't remember if I had to shim the pedestals but it was quite an easy job to check on the bench prior to fitting the heads.
have you had any issues with them, since install or have they been fine? my only concern is the extra moving parts to fail.. I currently have solid steel rockers so not even any pads to fall offIt was pretty straightforward to check the throw of the rockers over the valvestem. I can't remember if I had to shim the pedestals but it was quite an easy job to check on the bench prior to fitting the heads.
do you have the setup that uses the std shafts or the fancy set with the custom mounts and cradle
Graham said:
You can use them with hydro lifters, means you can set the preload without shiming the pedestals
I'm not sure that is entirely correct. The possible requirement to re-shim the pedestals is to ensure that at the position of max lift, the roller tip is directly on the centre point of the valve stem top, thus ensuring that when the rocker pressure / load is at a maximum, that there is minimal side force on the valve stem to ensure valve guide wear is kept to a minimum. (As previously mentioned by another forum member)I don't think the fitting of hydraulic lifters negates the fundamental geometry check requirement but am happy to be corrected if my thoughts are wrong. It's stood me in good order for the numerous engines rebuilt to date.
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