Off the shelf cam options for marine engines
#71
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this thread has been a good one with a lot of good information.lets not fuk it up and get it locked or removed.also,imo if you have 16 lifters in a engine and one fails[colapse]soon after startup i think the problem is that lifter,not the cam lobe.i had this happen on 3 different engines on the dyno,twice with 5w30 oil.all 3 had different cams.bck,throw all 16 of your old lifters in the trash.they can only cause you problems that you don,t need.jmo.
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Last edited by bck; 02-14-2016 at 01:26 AM.
#72
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See it how you like, but I can tell you my goal is NOT to cause issues. Myself having concerns on this thread because for 1, I have not even come close to power goals, and 2 I could possibly have a recipe for issues in my engines now... So yes cam specs linked to a failure is a big deal to us
#73
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When everythings right you can hear it on the Spintron , smooth , quiet , and it will make reliable power.
If it sounds like a hog eatin hickory nuts , its Thrashing and its gonna break ****. Power will suck because the valves cant seal.
If you watch the graphs on a Spintron , you can see the valve loft , watch it crash the lifter back on the back side of the cam .
Then you can see the push rod resonate from the impact , then the valve bounces from the Tuning Fork effect of the valve train trying to dampen out
the energy from the lifter to lobe crash.
#74
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no mine do ok, but lets face it, 630 out of a 540 is no home run at all... that's all I mean, I feel my valvetrain is compromised for making more power when it just does not, now if I saw the 68-700 mark I would understand the aggressive cam, I wish I knew more then, these make 30 more HP and 30 less TQ then my old engines that was VERY easy on valvetrain that's all.
cams now are 241/[email protected] 681/663 lift on a 112 LSA
I also think a 315 head would have done much better for me.
cams now are 241/[email protected] 681/663 lift on a 112 LSA
I also think a 315 head would have done much better for me.
Last edited by Full Force; 02-14-2016 at 07:54 AM.
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all good, just asking.
My old cams were specd for wet exhaust, low compression (so I could run cheap gas) and because I didn't want drive problems I wanted to keep the rpm low. When the engines went south I decided to try to get some more power out of them because the boat they are in now doesn't have any of the old limitations. I can't afford to change blocks or cranks or heads so I decided to change the cams.
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It starts at the lobe profile , goes to the valve train weight , ends at the spring rates .
When everythings right you can hear it on the Spintron , smooth , quiet , and it will make reliable power.
If it sounds like a hog eatin hickory nuts , its Thrashing and its gonna break ****. Power will suck because the valves cant seal.
If you watch the graphs on a Spintron , you can see the valve loft , watch it crash the lifter back on the back side of the cam .
Then you can see the push rod resonate from the impact , then the valve bounces from the Tuning Fork effect of the valve train trying to dampen out
the energy from the lifter to lobe crash.
When everythings right you can hear it on the Spintron , smooth , quiet , and it will make reliable power.
If it sounds like a hog eatin hickory nuts , its Thrashing and its gonna break ****. Power will suck because the valves cant seal.
If you watch the graphs on a Spintron , you can see the valve loft , watch it crash the lifter back on the back side of the cam .
Then you can see the push rod resonate from the impact , then the valve bounces from the Tuning Fork effect of the valve train trying to dampen out
the energy from the lifter to lobe crash.
#77
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I find this thread amusing..we've gone full circle and now off the shelf cams are good.
I based most of my engines w/ off the shelf cams as well as head so the end user later down the line could get the original parts and have similar hp/tq.
I find it funny some of the fan boys(combo,combo,combo,you know who you are) are now agreeing on off the shelf cams when all they did was push custom.
I always liked the crane cams(even when I got flamed),lunati,erson,and even edelbrock,I run Isky now but have used them all,and w/ good results and longevity.
A quick internet search will show who who is truely 2 faced when it comes to cams,right HP1 and buddy(keep learning from others people hard work and call it your own).guess your trying a new line to get customers.
I based most of my engines w/ off the shelf cams as well as head so the end user later down the line could get the original parts and have similar hp/tq.
I find it funny some of the fan boys(combo,combo,combo,you know who you are) are now agreeing on off the shelf cams when all they did was push custom.
I always liked the crane cams(even when I got flamed),lunati,erson,and even edelbrock,I run Isky now but have used them all,and w/ good results and longevity.
A quick internet search will show who who is truely 2 faced when it comes to cams,right HP1 and buddy(keep learning from others people hard work and call it your own).guess your trying a new line to get customers.
#78
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And when the valves are slamming shut and bouncing off their seats, power goes down, heat goes up. Even on what should have been milder cams, the unstable custom lobes caused significant damage to the valve seast. New AFR heads with less then 100 hours needed major work to fix the exhaust seats that had been pounded in to the head. The problem gets worse when the seat moves from the extreme heat and the valve seal gets worse. These were on 4400 max rpm engines. It was on two different engines and made me question the quality of the AFR heads before I realized completely what was going on.
I had three different motor renditions that I worked like a mad man trying to get cooling temperatures under control. I finally did but in the process I spent thousands of dollars and even more man hours playing around with the cooling system. I wonder if valve bounce could have been the culprit all along...
At this point Alex do you have any idea (dollar wise) what this has cost you and your company?
#79
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I often wondered why a new lobe could be created from scratch so fast and be at your door step the next day. I was beginning to think that maybe Kip had a magical horse show up his rectum. But up to this point I didn't much question it because there really wasn't any reported failures. Or maybe I just didn't put two and two together. I also wondered why a guy of your caliber was having custom cams spec'd and put in your motors. And why you just didn't open up a lobe book and pick your own.
I had three different motor renditions that I worked like a mad man trying to get cooling temperatures under control. I finally did but in the process I spent thousands of dollars and even more man hours playing around with the cooling system. I wonder if valve bounce could have been the culprit all along...
At this point Alex do you have any idea (dollar wise) what this has cost you and your company?
I had three different motor renditions that I worked like a mad man trying to get cooling temperatures under control. I finally did but in the process I spent thousands of dollars and even more man hours playing around with the cooling system. I wonder if valve bounce could have been the culprit all along...
At this point Alex do you have any idea (dollar wise) what this has cost you and your company?
#80
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