Theory Question: Valve Spring Oscillation
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,444
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
since you are drag racing a solid roller is the way to go with a quality rev limiter.
out of those two springs I would use the lower spring rate .800 lift and change the installed hieght +.050 to lowere the seat pressure to nearer 200#
The spring rate determines the open pressure.
About 165# is the max pressure that you can use with H-roller cams and generally even AFR mounts 145 - 155 # for h-roller setups.
out of those two springs I would use the lower spring rate .800 lift and change the installed hieght +.050 to lowere the seat pressure to nearer 200#
The spring rate determines the open pressure.
About 165# is the max pressure that you can use with H-roller cams and generally even AFR mounts 145 - 155 # for h-roller setups.
Race Director
Joined: May 2005
Posts: 10,674
Likes: 121
From: Millington Illinois
St. Jude Donor '08-'09
Hydraulic roller springs are around #325 spring rate. Neither spring you have will work with a hydraulic roller. The internals can't handle that much spring pressure. I have a XE288 HR cam with rev kit. Went a hair lighter spring pressure than recommended for my cam. The Rev kit adds #40 to seat pressure and #70 to open pressure applied to the lifter body, not the internals. This helps keep the heavy hydraulic roller lifter in contact with the cam lobe helping to prevent valve float at higher RPM. If you want to use a HR cam I would go with comps beehive springs. With them, a rev kit and the lighter valves on the eliminator heads 7000 RPM capability. If you use your springs a solid roller is your only option and lose the rev kit, you won't need it with those springs.
