View Full Version : What rockers under stock valve covers?


salemetro
04-22-2012, 04:02 PM
After using search and reading for a while, I'm still left scratching my head on this one....

What are the best 1.7 rockers (adjustable or not) that will fit under a stock valve cover? I've been looking at Jessel, YT, HS, etc, but am not sure which way to go to keep it all under the stock cover.

SF 1HOTLS1
04-22-2012, 05:04 PM
I here some people say YT and HS require getting that spacer for the stock valve cover. you can always just keep your stock rockers and upgrade them with the comp cams trunnion mod.

Darkman
04-22-2012, 06:02 PM
Jesel Sportsman Shaft Mounts (non-adjustable), Yella Terra Ultralites, and some of the Harland Sharp rockers are designed to fit underneath the stock valve cover. There may be exceptions, and there may be cases where you actually need to file or Dremel a place or two to make it work.

I would also be concerned with selecting a rocker that will handle the spring pressure. For example, the Jesels are rated to 900 pounds of open spring pressure, whereas the Yella Terras, (and stock rockers for that matter) are only reliable up to 400 pounds of open spring pressure.

salemetro
04-22-2012, 06:12 PM
I here some people say YT and HS require getting that spacer for the stock valve cover. you can always just keep your stock rockers and upgrade them with the comp cams trunnion mod.

I already have the trunion upgrade....swapped cams and looking for a better swipe pattern. Spacer for the valve cover? Ill have to do some more searching....

Darkman
04-22-2012, 06:15 PM
http://www.summitracing.com/search/brand/UMI-Performance/Product-Line/UMI-Performance-LS-Series-Aluminum-Valve-Cover-Spacers/?autoview=SKU

salemetro
04-22-2012, 06:15 PM
Jesel Sportsman Shaft Mounts (non-adjustable), Yella Terra Ultralites, and some of the Harland Sharp rockers are designed to fit underneath the stock valve cover. There may be exceptions, and there may be cases where you actually need to file or Dremel a place or two to make it work.

I would also be concerned with selecting a rocker that will handle the spring pressure. For example, the Jesels are rated to 900 pounds of open spring pressure, whereas the Yella Terras, (and stock rockers for that matter) are only reliable up to 400 pounds of open spring pressure.

Thanks for the heads up.....im at 400 closed. Which jessel's are you meaning?

salemetro
04-22-2012, 06:17 PM
http://www.summitracing.com/search/brand/UMI-Performance/Product-Line/UMI-Performance-LS-Series-Aluminum-Valve-Cover-Spacers/?autoview=SKU

Thanks for the link! :)

Darkman
04-22-2012, 06:25 PM
Thanks for the heads up.....im at 400 closed. Which jessel's are you meaning?


Jesel KSS-307070

http://www.summitracing.com/parts/JES-KSS-307070/

(The Summit picture shows an adjustable version, but these are not adjustable).

salemetro
04-22-2012, 07:04 PM
Jesel KSS-307070

http://www.summitracing.com/parts/JES-KSS-307070/

(The Summit picture shows an adjustable version, but these are not adjustable).

Chunk o $$$....but gonna have to throw down the funds if that's all that is available. Thanks :-)

ZeeOSix
04-22-2012, 07:23 PM
... the Yella Terras, (and stock rockers for that matter) are only reliable up to 400 pounds of open spring pressure.

Where did the 400 lbs open spring pressure specification come from for the stock rocker arms?

Darkman
04-22-2012, 07:45 PM
Where did the 400 lbs open spring pressure specification come from for the stock rocker arms?


http://ls1tech.com/forums/15983303-post14.html
http://ls1tech.com/forums/generation-iii-internal-engine/1534309-car-running-extremely-rich-very-rough-idle.html
http://ls1tech.com/forums/generation-iii-internal-engine/1523434-broke-rocker.html