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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) |
Originally Posted by SB
(Post 4310842)
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 http://www.iskycams.com/tech-tips-2000.html#2007 |
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. |
Originally Posted by sutphen 30
(Post 4310946)
http://www.iskycams.com/tech-tips-2000.html#2003 |
Originally Posted by sutphen 30
(Post 4310950)
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. 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 |
Originally Posted by Bawana
(Post 4310778)
Joe. who is running 600lbs on hydraulic lifters? I was told anything over 500lbs will sink the best of them. I was always told that; more then needed spring pressure = short valve train life, and will rob power.
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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 |
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 |
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.
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Originally Posted by abones
(Post 4310972)
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. |
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