Cam recommendation for Blower Motor
02-15-2003, 08:11 AM
#21
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I think the tale is told more in the duration numbers @ .100" and .200" lift when comparing solid vs. hidraulic rollers with the same duration @ .050.
Bob,
What kind of compression ratio and heads were you running on that 500"? That is the closest combo to mine I have seen where someone has dyno numbers. As I mentioned I run 13.2:1 compression, Dart 325 pro1 heads (ported), Merlin single plane intake with an adapter and a Nickerson stage 5 1050 (1175 cfm).
Thanks,
Craig
Bob,
What kind of compression ratio and heads were you running on that 500"? That is the closest combo to mine I have seen where someone has dyno numbers. As I mentioned I run 13.2:1 compression, Dart 325 pro1 heads (ported), Merlin single plane intake with an adapter and a Nickerson stage 5 1050 (1175 cfm).
Thanks,
Craig
02-16-2003, 09:25 AM
#23
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Wette Vette/
Motors were actually de-tuned ex Merc Class 1's. 3.92 stroke, 4.530 bores, 6.535 rods, 9.5:1, Dart 14 degree big chief heads. The heads really don't even begin to work until you get .700" plus lift cams and they like 6000+. But they did ok.
Motors were actually de-tuned ex Merc Class 1's. 3.92 stroke, 4.530 bores, 6.535 rods, 9.5:1, Dart 14 degree big chief heads. The heads really don't even begin to work until you get .700" plus lift cams and they like 6000+. But they did ok.
02-16-2003, 05:21 PM
#25
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Originally posted by WETTE VETTE
I think the tale is told more in the duration numbers @ .100" and .200" lift when comparing solid vs. hidraulic rollers with the same duration @ .050.
Thanks,
Craig
I think the tale is told more in the duration numbers @ .100" and .200" lift when comparing solid vs. hidraulic rollers with the same duration @ .050.
Thanks,
Craig
Herbert cams are ground for either one.
02-16-2003, 06:13 PM
#26
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Hello, Guys,
Solid lifter cams, roller or flat tappet, have an acceleration ramp to get things moving. The ramp is usually several degrees of rotation and equal in lifter rise to the lash divided by the rocker ratio. The same is true on the closing side. Hydraulics do not need this as the hydraulic part takes up the initial shock of the movement. A solid lifter on a hydraulic cam will have no acceleration ramp to soften the blow to the valve train. This can cause rapid wear-kind of like striking the valve train with a small hammer each cycle. A hydraulic lifter on a solid cam will have a long duration at very low lift. Both are problems, both have been done with varying results. If you didn't need different cams, they wouldn't make the investment in the two designs.
WETTE VETTE has a good point also in that the numbers at .100" and .200", etc. are very important in the way a cam acts. Most manufacturers will give you these numbers in their catalogues under lobe specifications. Books are written on this subject
Solid lifter cams, roller or flat tappet, have an acceleration ramp to get things moving. The ramp is usually several degrees of rotation and equal in lifter rise to the lash divided by the rocker ratio. The same is true on the closing side. Hydraulics do not need this as the hydraulic part takes up the initial shock of the movement. A solid lifter on a hydraulic cam will have no acceleration ramp to soften the blow to the valve train. This can cause rapid wear-kind of like striking the valve train with a small hammer each cycle. A hydraulic lifter on a solid cam will have a long duration at very low lift. Both are problems, both have been done with varying results. If you didn't need different cams, they wouldn't make the investment in the two designs.
WETTE VETTE has a good point also in that the numbers at .100" and .200", etc. are very important in the way a cam acts. Most manufacturers will give you these numbers in their catalogues under lobe specifications. Books are written on this subject
Last edited by blown1500; 02-16-2003 at 06:22 PM.
02-16-2003, 06:50 PM
#27
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Wette Vette/
We changed the cam when we went to lower compression. The Merc cam originally had lifts of .759/.714 with 1.7 rockers, the motors actually had 1.8's. Duration with 1.7 was 266/274 at .050. When they spent their time up around 7000 that's what they need to make their hp. I am setting up some small blower motors and I going to run a solid roller .678/.651 with 254/262 at .050 and 112 sep.. It's not a wild cam and I had great lifter life with them last year. From a hp standpoint it's not supposed to be as good as the 420 lobe cam (.714/.714) but lifter life is better. Good luck!
We changed the cam when we went to lower compression. The Merc cam originally had lifts of .759/.714 with 1.7 rockers, the motors actually had 1.8's. Duration with 1.7 was 266/274 at .050. When they spent their time up around 7000 that's what they need to make their hp. I am setting up some small blower motors and I going to run a solid roller .678/.651 with 254/262 at .050 and 112 sep.. It's not a wild cam and I had great lifter life with them last year. From a hp standpoint it's not supposed to be as good as the 420 lobe cam (.714/.714) but lifter life is better. Good luck!
02-17-2003, 07:58 PM
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Blown 1500,
I have the above mentioned Lunati cam in a 502 supercharged Dart heads done by Jim V running about 6psi. In your opinion would the 741 Crane cam be worth switching to?
Thank You
I have the above mentioned Lunati cam in a 502 supercharged Dart heads done by Jim V running about 6psi. In your opinion would the 741 Crane cam be worth switching to?
Thank You
