Anyone running a solid roller?
01-01-2007, 10:15 PM
#7
It's not bad for a cruiser (maybe not a true daily driver) - lash adjustments are necessary often if you have a crappy setup - otherwise you should check it every couple of months or every thousand or so miles, which you should be doing even in a hydraulic roller setup or any engine with substantial modifications done to it. It's not a factory motor, so it shouldn't be treated like one.
As for drivability, most street roller profiles nowadays are excellent on the street due to the extremely fast ramp rates that a solid roller valvetrain allows. A SR setup allows three basic advantages if you're willing to accept the maintenance requirements:
1) Better idle for a given SR profile vs HR due to the low overlap at the advertised duration at .006" - as an example, a SR lobe may be rated at 279 advertised, but may be a 244 at .050" - equivalent to an aggressive 230 @ .050" duration hydraulic lobe.
2) This aggressiveness off the seat is accomplished because of the superior valve control. The SR lobe will also allow for faster revving due to superior harmonics/control of the valve.
3) What the above two allow is for more topend power without sacrificing low-end or midrange torque all without the need to run a lot of static compression.
When you see a 270/280 SR grind, it's not a whole lot bigger than a 250/260 HR grind, as it needs about the same compression and will idle the same - the difference is it will make more power, deliver it smoother, and be every bit as streetable as the smaller HR grind. The problem is of course cost and maintenance.
Most people don't think about a SR for a more mild mannered build due to the overall "aggressiveness" of the lobes and the spring requirements, but I think that's a mistake. The HR was designed to be a set and forget type of thing, but with LSK lobes and the like, a HR cam can require quite a bit of attention to detail, powerful double springs that will need to be checked or possibly even replaced every 15-20k miles, and sometimes healthy compression to get torque back all without the benefits of the ultra smooth delivery and upper RPM stability of a SR set up.
A SR doesn't have to be for a big RPM engine though, as there are plenty of street lobes available. These aren't as aggressive (maybe only slightly more so than an XE-R lobe) but still allow for very nice idle quality and streetability with a larger duration at .050" and thus more power. If you have a good SD tune, a SR can be a great choice for a street/strip car that seems to be often overlooked.
As for drivability, most street roller profiles nowadays are excellent on the street due to the extremely fast ramp rates that a solid roller valvetrain allows. A SR setup allows three basic advantages if you're willing to accept the maintenance requirements:
1) Better idle for a given SR profile vs HR due to the low overlap at the advertised duration at .006" - as an example, a SR lobe may be rated at 279 advertised, but may be a 244 at .050" - equivalent to an aggressive 230 @ .050" duration hydraulic lobe.
2) This aggressiveness off the seat is accomplished because of the superior valve control. The SR lobe will also allow for faster revving due to superior harmonics/control of the valve.
3) What the above two allow is for more topend power without sacrificing low-end or midrange torque all without the need to run a lot of static compression.
When you see a 270/280 SR grind, it's not a whole lot bigger than a 250/260 HR grind, as it needs about the same compression and will idle the same - the difference is it will make more power, deliver it smoother, and be every bit as streetable as the smaller HR grind. The problem is of course cost and maintenance.
Most people don't think about a SR for a more mild mannered build due to the overall "aggressiveness" of the lobes and the spring requirements, but I think that's a mistake. The HR was designed to be a set and forget type of thing, but with LSK lobes and the like, a HR cam can require quite a bit of attention to detail, powerful double springs that will need to be checked or possibly even replaced every 15-20k miles, and sometimes healthy compression to get torque back all without the benefits of the ultra smooth delivery and upper RPM stability of a SR set up.
A SR doesn't have to be for a big RPM engine though, as there are plenty of street lobes available. These aren't as aggressive (maybe only slightly more so than an XE-R lobe) but still allow for very nice idle quality and streetability with a larger duration at .050" and thus more power. If you have a good SD tune, a SR can be a great choice for a street/strip car that seems to be often overlooked.