Comp 921 dual springs?
#1
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Comp 921 dual springs?
I just ordered a kit from Speed Inc. I guess I should of asked are they any good of a spring? DO they last, I drive my car everyday. THanks.
#4
Spring Choice?
Originally Posted by DenzSS
I'm using them on my solid roller. I'll let you know how they shake out in a week or two. Good looking spring, but thats the most I can say at this point.
The 921 is a very high quality spring and is an excellent choice for a hydraulic roller, but I'm fairly confident that it is NOT a good choice for a solid roller. You need more seat pressure as well as spring rate on a solid roller application. Who recommended that spring in a solid roller application?
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Comp recommended it for the custom cam they ground. The cam itself doesn't have a great amount of gross lift, we're making it up in the rocker. Rockers and lifters are Jesel.
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Well making it up on the rockers puts the same stress on the springs that the high lift on the cam would. I dont believe the lift is the problem with solid rollers, the problem is the extreme ramp rates, that is the reason you need so much seat pressure to keep from hanging a valve open, all the solid rollers I have seen have HUGE springs in them
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#12
One more thing...
Guys...I gotta chime in here one more time. Just because the spring is rated to .600 or .650 lift WITH A HYDRAULIC ROLLER, doesn't mean you can take the same spring with a solid roller and expect the same results. A solid roller does have completely different ramps and acceleration rates, and if you were able to effectively control a solid cam with such light spring pressures, it certainly wouldn't have much of a power gain potential over the same grind with a hydraulic lifter. The benefit of a solid roller is the additional area under the curve the more aggressive cam profiles provide....Without that, why bother going solid at all and deal with the occasional valve lash etc. Also, with a solid valvetrain, spring pressure is your friend as it keeps all the parts in direct contact with one another at all times....No jarring motion and valves boucing off the seat of the cam because there wasn't enough seat pressure to keep it glued to the camshaft....Thats more dangerous than higher spring pressures and is more likey to cause parts failure.
Thats it....I'm done preaching now
All I can say is good luck if you opt to try it.....just be on the look-out for signs of valve float.
Tony M.
Thats it....I'm done preaching now
All I can say is good luck if you opt to try it.....just be on the look-out for signs of valve float.
Tony M.