Cam intensity question
05-31-2015, 06:22 AM
#21
Gold Member
Just bought my cam/valvetrain a few months back.
55mm solid roller
Isky tool room springs.
Jesel rocker arms
Morel lifter (.904 with an .810 wheel)
Closed psi- 195
Open psi-540
Cam is 720 lift and mid 200's @.050 ( I can't remember the exact duration but it's in the 250 range)
55mm solid roller
Isky tool room springs.
Jesel rocker arms
Morel lifter (.904 with an .810 wheel)
Closed psi- 195
Open psi-540
Cam is 720 lift and mid 200's @.050 ( I can't remember the exact duration but it's in the 250 range)
05-31-2015, 08:20 AM
#22
Registered
Did a quick search, and Here's an old thread with Harold Brookshire and Mike Jones responding to someone asking about IR cams.
Jones does mention use in HR's
http://speedtalk.com/forum/viewtopic.php?t=8711
Jones does mention use in HR's
http://speedtalk.com/forum/viewtopic.php?t=8711
http://www.iskycams.com/tech-tips-2000.html#2007
05-31-2015, 08:26 AM
#23
Registered
heres an idea,,stop using drag race cams in a marine motor.unless your gonna run your engine 7-10 secs at a time,then your ok.
you guys can do the math,top sportsman sbc,(sbx) 1.1" lift,425lbs seat,1195lbs over the nose,,springs are good for 1 season ~12 events.aluminum rods are good for 2 seasons.And I check the springs every week on the car.
you guys can do the math,top sportsman sbc,(sbx) 1.1" lift,425lbs seat,1195lbs over the nose,,springs are good for 1 season ~12 events.aluminum rods are good for 2 seasons.And I check the springs every week on the car.
05-31-2015, 08:42 AM
#24
Registered
iTrader: (1)
05-31-2015, 09:02 AM
#25
heres an idea,,stop using drag race cams in a marine motor.unless your gonna run your engine 7-10 secs at a time,then your ok.
you guys can do the math,top sportsman sbc,(sbx) 1.1" lift,425lbs seat,1195lbs over the nose,,springs are good for 1 season ~12 events.aluminum rods are good for 2 seasons.And I check the springs every week on the car.
you guys can do the math,top sportsman sbc,(sbx) 1.1" lift,425lbs seat,1195lbs over the nose,,springs are good for 1 season ~12 events.aluminum rods are good for 2 seasons.And I check the springs every week on the car.
It be nice to see cam cards from cam companies putting duration numbers other than at .050 and .004 on their specs.
Camshaft intensity is a measurement term coined by Harvey Crane to compare ramp characteristics of camshafts.
• Hydraulic Intensity is the difference between the .004 duration and the .050 duration.
• Minor intensity is the difference between the .010 duration and the .050 duration.
• Major intensity is the difference between the .020 duration and the .050 duration
Lower numbers indicate more radical profiles but too low can be too radical and lead to noisy valve train and even to broken parts
• Hydraulic Intensity is the difference between the .004 duration and the .050 duration.
• Minor intensity is the difference between the .010 duration and the .050 duration.
• Major intensity is the difference between the .020 duration and the .050 duration
Lower numbers indicate more radical profiles but too low can be too radical and lead to noisy valve train and even to broken parts
05-31-2015, 09:07 AM
#27
Looking thru comp cams master lobe catalog, they have specific marine lobes. These are their basic marine camshaft lobe profiles....for a cam duration like mine for example of 236*, it has a lobe lift of .357. and .607 valve lift with 1.7 rocker.
XTREME MARINE™ HYDRAULIC ROLLERS
These profiles use the same design techniques of the baseline Xtreme Energy™Hydraulic Rollers but have been opti-mized to increase power and durability when run at steady rpm for extended periods of time. Specifically designed
for big blocks with heavier valve train components
1.800.999.0853
HYDRAULIC ROLLER
HYDRAULIC ROLLER
16
LOBE RATED DURATION IN LOBE TAPPET LIFT @ THEORETICAL VALVE LIFT
NUMBER DURATION DEGREES LIFT TDC @
“0” LASH ROCKER ARM RATIO
CAMSHAFT TYPE
@ .050” @ .200” 106° 110° 1.5 1.6 1.7
3033 264 212 135 .341 .050 .040 .512 .546 .580
3034 270 218 141 .347 .059 .048 .521 .555 .590
3035 276 224 147 .353 .069 .056 .530 .565 .600
3036 282 230 152 .355 .080 .066 .533 .568 .604
3037 288 236 158 .357 .091 .076 .536 .571 .607
3038 294 242 163 .360 .102 .087 .540 .576 .612
3039 300 248 169 .362 .114 .098 .543 .579 .615
These profiles use the same design techniques of the baseline Xtreme Energy™Hydraulic Rollers but have been opti-mized to increase power and durability when run at steady rpm for extended periods of time. Specifically designed
for big blocks with heavier valve train components
1.800.999.0853
HYDRAULIC ROLLER
HYDRAULIC ROLLER
16
LOBE RATED DURATION IN LOBE TAPPET LIFT @ THEORETICAL VALVE LIFT
NUMBER DURATION DEGREES LIFT TDC @
“0” LASH ROCKER ARM RATIO
CAMSHAFT TYPE
@ .050” @ .200” 106° 110° 1.5 1.6 1.7
3033 264 212 135 .341 .050 .040 .512 .546 .580
3034 270 218 141 .347 .059 .048 .521 .555 .590
3035 276 224 147 .353 .069 .056 .530 .565 .600
3036 282 230 152 .355 .080 .066 .533 .568 .604
3037 288 236 158 .357 .091 .076 .536 .571 .607
3038 294 242 163 .360 .102 .087 .540 .576 .612
3039 300 248 169 .362 .114 .098 .543 .579 .615
05-31-2015, 09:21 AM
#28
Then their is their "high lift" version of their marine hydraulic rollers. A 236* lobe for their high lift version, has a .360 lobe lift, with .612 at the valve with 1.7. While I certainly don't think comp cams is god, they aren't new to the cam business, marine, endurance racing, etc. They have quite a bit of a knowledge base on camshaft lobes. Also, when looking thru cranes literature, I have not seen anything with a "marine" useage or endurance useage, with anything near .680-.700 lift with a 1.7 rocker, even on the longer duration stuff.
XTREME MARINE™ HYDRAULIC ROLLERS - HIGH LIFT
These have the same ramp designs as the lower lift Xtreme Marine
™
designs but have higher lift to enhance power
output with cylinder head and engine modifications.
LOBE RATED DURATION IN LOBE TAPPET LIFT @ THEORETICAL VALVE LIFT
NUMBER DURATION DEGREES LIFT TDC @
“0” LASH ROCKER ARM RATIO
CAMSHAFT TYPE
@ .050” @ .200” 106° 110° 1.5 1.6 1.7
3473 290 234 152 .360 .081 .068 .540 .576 .612
3474 292 236 154 .360 .085 .071 .540 .576 .612
3410 294 238 154 .350 .088 .075 .525 .560 .595
3475 294 238 156 .360 .088 .075 .540 .576 .612
3376 296 240 157 .360 .092 .078 .540 .576 .612
3411 300 244 159 .350 .099 .085 .525 .560 .595
3370 304 248 167 .380 .107 .092 .570 .608 .646
3377 306 250 166 .360 .111 .096 .540 .576 .612
3371 308 254 171 .380 .119 .103 .570 .608 .646
3372 314 258 175 .380 .126 .111 .570 .608 .646
3373 318 262 179 .380 .134 .118 .570 .608 .646
3374 322 266 182 .380 .142 .126 .570 .608 .646
3375 326 270 186 .380 .149 .134 .570 .608 .646
3447 330 274 190 .380 .157 .141 .570 .608 .64
These have the same ramp designs as the lower lift Xtreme Marine
™
designs but have higher lift to enhance power
output with cylinder head and engine modifications.
LOBE RATED DURATION IN LOBE TAPPET LIFT @ THEORETICAL VALVE LIFT
NUMBER DURATION DEGREES LIFT TDC @
“0” LASH ROCKER ARM RATIO
CAMSHAFT TYPE
@ .050” @ .200” 106° 110° 1.5 1.6 1.7
3473 290 234 152 .360 .081 .068 .540 .576 .612
3474 292 236 154 .360 .085 .071 .540 .576 .612
3410 294 238 154 .350 .088 .075 .525 .560 .595
3475 294 238 156 .360 .088 .075 .540 .576 .612
3376 296 240 157 .360 .092 .078 .540 .576 .612
3411 300 244 159 .350 .099 .085 .525 .560 .595
3370 304 248 167 .380 .107 .092 .570 .608 .646
3377 306 250 166 .360 .111 .096 .540 .576 .612
3371 308 254 171 .380 .119 .103 .570 .608 .646
3372 314 258 175 .380 .126 .111 .570 .608 .646
3373 318 262 179 .380 .134 .118 .570 .608 .646
3374 322 266 182 .380 .142 .126 .570 .608 .646
3375 326 270 186 .380 .149 .134 .570 .608 .646
3447 330 274 190 .380 .157 .141 .570 .608 .64
05-31-2015, 09:31 AM
#29
Registered
Also for those who have a Dyno-Sim program plug in a more aggressive cam profile, see what the HP/TQ gain might be and decide if the gain is worth the reliability issues that are associated with the profile when used for marine long term usage! I'll bet it is not worth the grief.
05-31-2015, 09:55 AM
#30
Also for those who have a Dyno-Sim program plug in a more aggressive cam profile, see what the HP/TQ gain might be and decide if the gain is worth the reliability issues that are associated with the profile when used for marine long term usage! I'll bet it is not worth the grief.
I guess time will tell how their valvetrain holds up, and if the extra little bit of power, was worth it or not for them.
From the little I am learning on this stuff, is there is no getting around increasing lobe intensity increase, if duration doesnt grow with the lobe size. So, while most think they are simply adding valve lift, they are also increasing lobe aggressiveness..?...
Would it be wise to assume, keep gentle ramps, keep lobe lift down, run enough, but not excessive spring pressure, and make your power in other areas of the build, if long valvetrain life is what you want. Especially on forced induction marine stuff.
