Cam duration comparison between hyd. roller and solid roller ?
Thread Starter
Melting Slicks
Joined: May 2001
Posts: 3,270
Likes: 26
From: Winchester VA
Cruise-In V Veteran
Cam duration comparison between hyd. roller and solid roller ?
In certain recent hot topics a comparison between durations of hyd. roller (HR) and solid roller (SR) cams has been alluded to. Something to the effect that for equality, an HR cam would have about 10* less duration.
Is that to say that an HR with 244/250 and an SR with 254/260 will have very similar driveability characteristics? If so the big question I have is...why?
The only difference I can think of is lash, but it just doesn't seem that it would have that much effect.
Please help... :confused:
Is that to say that an HR with 244/250 and an SR with 254/260 will have very similar driveability characteristics? If so the big question I have is...why?
The only difference I can think of is lash, but it just doesn't seem that it would have that much effect.
Please help... :confused:
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Re: Cam duration comparison between hyd. roller and solid roller ? (Ski2Tee)
Hey Steve, if you have time call the guys at this site, Bob will answer the phone probably and can answer your questions, he is extremely helpful http://www.bulletcams.com They re-ground my cam for me.
I asked the same questions and he said to add 10 degrees for the equivelant SR cam but stressed that the duration is a small part of it and that it is very important to know the lifts=ramp at .100. 200. 300. 400 etc for a real comparison.
I asked the same questions and he said to add 10 degrees for the equivelant SR cam but stressed that the duration is a small part of it and that it is very important to know the lifts=ramp at .100. 200. 300. 400 etc for a real comparison.
Burning Brakes
Joined: Nov 2001
Posts: 1,241
Likes: 9
From: Houston TX
Re: Cam duration comparison between hyd. roller and solid roller ? (Ski2Tee)
the difference in seat to seat timing changes for the same .050" timing when comparing those differing lobe designs. so the amount of overlap changes.
this coupled with ramp rate differences also means the lobe separation angle isn't directly comparable.
however, i don't think any rule will tell you much. there can be 2 cams with almost the same specs and same lifter type that end up having different demeanor and power levels. with some experience you can get a good feel for how a cam will run by looking at all the events (vo/vc, durations at different lifts, lsa, etc).
-michael
this coupled with ramp rate differences also means the lobe separation angle isn't directly comparable.
however, i don't think any rule will tell you much. there can be 2 cams with almost the same specs and same lifter type that end up having different demeanor and power levels. with some experience you can get a good feel for how a cam will run by looking at all the events (vo/vc, durations at different lifts, lsa, etc).
-michael
Melting Slicks
Joined: Sep 2000
Posts: 3,099
Likes: 0
From: PITTSBURGH PA
Cruise-In IV Veteran
Cruise-In V Veteran
Re: Cam duration comparison between hyd. roller and solid roller ? (MSR)
THE 10% IS A BASIC RULE OF THUMB
LIKE MY SOLID ROLLER IS 244 AT 50 A COMPARIBLE HR WOULD BE 234 AT 50
THAT IS WHY I AM SAYING THAT 219 HR IN A 383 OR SMALLER IS A PRETTY HEALTHY CAM FOR THE CUBES :cheers:
LIKE MY SOLID ROLLER IS 244 AT 50 A COMPARIBLE HR WOULD BE 234 AT 50
THAT IS WHY I AM SAYING THAT 219 HR IN A 383 OR SMALLER IS A PRETTY HEALTHY CAM FOR THE CUBES :cheers:
